1. Describe the Neurologic Control of 3.

Trace the movement of air into and

breathing. out of the lungs.
Breathing usually does not require any 1. Inhale: Air enters your body through
thought, because it is controlled by the your nose or mouth.
autonomic nervous system, also
called involuntary nervous system.
2. Warming and Filtering: The air
The brainstem is the part of the brain passes through the nasal cavity or
responsible for controlling breathing. It oral cavity, where it is warmed, filtered,
contains two specific areas: and humidified.

Medulla oblongata: This area sends

3. Down the Throat: The air travels
signals to the diaphragm and intercostal
down the pharynx, a common pas-
muscles, which are the main muscles
sageway for both air and food.
used in breathing.
Pons: This area helps to regulate the
rate and depth of breathing. 4. Voice Box: It then passes through the
larynx or voice box, containing the vo-
The lungs also play a role in breathing cal cords.
control. They contain chemoreceptors
that detect changes in blood oxygen 5. Windpipe: The air enters the trachea
and carbon dioxide levels. When these or windpipe, a tube that carries air to
levels change, the chemoreceptors the lungs.
send signals to the brainstem to adjust
breathing accordingly.
6. Branching: The trachea divides into
two bronchi, one for each lung.
2. Elaborate on the effect of surfac-
tant to the lungs.
Surfactant is a substance produced by 7. Lungs: The bronchi branch further
the lungs that helps keep the tiny air into smaller tubes called bronchioles.
sacs (alveoli) open. Without it, the alve-
oli would collapse after each breath, 8. Air Sacs: The bronchioles end in tiny
making it difficult to breathe. It's like air sacs called alveoli.
adding a little soap to water to reduce
surface tension. Surfactant does a sim-
9. Oxygen Exchange: Oxygen from the
ilar thing in the lungs, making it easier
inhaled air diffuses through the thin
for air to go in and out.
walls of the alveoli into the blood, while
carbon dioxide from the blood diffuses
into the alveoli.
10. Exhale: The air, now enriched with This continuous gas exchange is es-
carbon dioxide, is exhaled back through sential for maintaining the body's oxy-
the same path it took in, eventually leav- gen supply and removing carbon diox-
ing the body through the nose or mouth. ide.

4. What is the relationship between 6. Describe the gas exchange be-

lung volume and pressure to the of tween the tissues and capillaries.
air in the lungs? Gas exchange is the process by which
Lung volume and pressure are in- oxygen diffuses from the blood into the
versely related to the amount of air in tissues, while carbon dioxide diffuses
the lungs. from the tissues into the blood. This vital
process occurs at the level of the capil-
When lung volume increases (like laries, the smallest blood vessels.
when you inhale), pressure de-
creases. This lower pressure allows air The Process:
to flow into the lungs. 1. Oxygen Diffusion:
When lung volume decreases (like Oxygen-rich blood from the lungs
when you exhale), pressure in- enters the capillaries.
creases. This higher pressure forces ● The partial pressure of oxygen in the
air out of the lungs. blood is higher than that in the sur-
rounding tissues.
Think of it like a balloon: the more air ● This pressure difference causes ox-
you blow into it, the bigger it gets (higher ygen molecules to diffuse out of the ca-
volume). As the balloon gets bigger, the pillaries and into the tissues.
pressure inside decreases. When you ● Oxygen is then utilized by cells for
let go of the balloon, the pressure inside cellular respiration.
increases, forcing the air out.
2. Carbon Dioxide Diffusion:
● As cells perform cellular respiration,
5. Describe the gas exchange be- they produce carbon dioxide as a waste
tween the lungs and capillaries. product.
The lungs and capillaries work together ● The partial pressure of carbon diox-
to exchange gases. During inhalation, ide in the tissues is higher than that in
oxygen-rich air enters the lungs and dif- the blood.
fuses into the capillaries. Red blood ● This pressure difference causes car-
cells in the capillaries bind to oxygen, bon dioxide molecules to diffuse from
transporting it to body cells. the tissues into the capillaries.
At the same time, carbon dioxide, a ● The carbon dioxide is then trans-
waste product, diffuses from the capil- ported back to the lungs to be exhaled.
laries into the alveoli and is exhaled.
7. Compare the different lung vol- can be inhaled after a normal ex-
umes. halation. It's the sum of TV and
Lung volumes are the different IRV.
amounts of air that can be inhaled or ex- • Functional Residual Capacity
haled by the lungs. These volumes are (FRC): This is the amount of air
measured in milliliters (mL) and can remaining in the lungs at the end
vary based on factors like age, gender, of a normal exhalation. It's the
and overall health. Here's a breakdown sum of ERV and RV.
of the key lung volumes: • Vital Capacity (VC): This is the
maximum amount of air that can
Primary Lung Volumes be exhaled after a maximum inha-
lation. It's the sum of TV, IRV, and
• Tidal Volume (TV): This is the
ERV.
amount of air inhaled or exhaled
• Total Lung Capacity (TLC): This
in a normal, quiet breath.
is the maximum amount of air that
• Inspiratory Reserve Volume
the lungs can hold. It's the sum of
(IRV): This is the additional
all four primary lung volumes.
amount of air that can be inhaled
after a normal inhalation. Comparison Table
• Expiratory Reserve Volume Lung Volume Description
(ERV): This is the additional Tidal Volume Normal breath
amount of air that can be exhaled (TV)
after a normal exhalation. Inspiratory Re- Extra inhale
• Residual Volume (RV): This is serve Volume
the amount of air that remains in (IRV)
the lungs after a maximum exha- Expiratory Re- Extra exhale
lation. serve Volume
(ERV)
Note: These volumes can be measured
Residual Vol- Air left after
using a spirometer. They are important
ume (RV) max exhale
for assessing lung function and diag-
nosing respiratory conditions. Inspiratory Ca- Max inhale af-
pacity (IC) ter normal ex-
8. Compare the different lung capac- hale
ities. Functional Re- Air left after
sidual Capacity normal exhale
Lung Capacities (Combinations of (FRC)
Volumes) Vital Capacity Max exhale af-
(VC) ter max inhale
• Inspiratory Capacity (IC): This is
Total Lung Ca- Max lung ca-
the maximum amount of air that
pacity (TLC) pacity
9. How can the respiratory system af- • Emotions: Stress, excitement, or
fect the pH of the blood? anxiety can make you breathe
more quickly and deeply.
The respiratory system affects blood pH • Health conditions: Some health
by controlling the amount of carbon di- problems, like asthma or COPD,
oxide (CO2) in the body. can affect your breathing.
• Altitude: At higher altitudes,
• When you breathe out, CO2 is
there's less oxygen in the air, so
expelled from your body.
you breathe faster to get enough.
• CO2 reacts with water in your
• Body temperature: When you're
blood to form carbonic acid.
hot, your body needs more oxy-
• Carbonic acid breaks down into
gen, so you breathe faster.
hydrogen ions (H+) and bicar-
• Medications: Some medications
bonate ions.
can affect your breathing.
• More CO2 = more carbonic acid
= more H+ ions = lower blood These factors work together to help
pH (more acidic). your body get the oxygen it needs and
• Less CO2 = less carbonic acid remove the waste products like carbon
= fewer H+ ions = higher blood dioxide.
pH (less acidic).
11. What is the difference of the right
So, by adjusting how fast or slow you and left lung?
breathe, your body can regulate the
amount of CO2 in your blood and, there- Right Lung:
fore, the pH.
• Size: Larger than the left lung.
10. Give different factors which may • Shape: Roughly cone-shaped,
affect the rate and depth of respira- with a wider base.
tion. • Number of lobes: Three (upper,
middle, and lower).
• Physical activity: When you ex- • Aspiration: More prone to aspira-
ercise, your body needs more ox- tion (inhaling foreign objects) due
ygen, so you breathe faster and to its shorter and wider bronchus.
deeper.
• Carbon dioxide levels: If there's Left Lung:
too much carbon dioxide in your
blood, your body will breathe • Size: Smaller than the right lung.
faster to get rid of it. • Shape: Roughly cone-shaped,
• Oxygen levels: If there's not with a narrower base.
enough oxygen in your blood, • Number of lobes: Two (upper
your body will breathe faster to and lower).
take in more.
 • Aspiration: Less prone to aspira- • Breathing difficulty: This can
tion due to its longer and narrower lead to shortness of breath, chest
bronchus. pain, and rapid breathing.
• Tension pneumothorax: In se-
Overall: Both lungs are essential for vere cases, the air pressure in the
breathing, but their differences in size, pleural space can become so high
shape, and number of lobes can affect that it compresses the heart and
their function, particularly in terms of as- lungs. This condition is known as
piration tension pneumothorax. As more
air enters the pleural space, the
12. Describe how the lack of oxygen
pressure increases, pushing the
and increase in carbon dioxide affect
lung and heart away from the
breathing
chest wall. This can cause the
• Less oxygen: When there’s less heart to shift to the opposite side
oxygen in the air, your body of the chest, compressing the
needs to work harder to get vena cava, a large blood vessel
enough. that returns blood to the heart.
• More carbon dioxide: Too much This can lead to decreased blood
carbon dioxide can make it hard flow to the heart and brain, caus-
to breathe. ing symptoms such as:
• Increased breathing: Your body o Rapid heart rate

will try to breathe faster and o Low blood pressure

o Difficulty breathing
deeper to get more oxygen.
o Chest pain
• Acidic blood: Over time, too
much carbon dioxide can make o Shock

your blood more acidic.

14. What are the effect of smoking in
• Difficulty breathing: This can
the lungs?
make it hard to breathe and feel
tired. Smoking is harmful to your lungs. It
can cause a variety of serious health
13. Describe what happens when
problems, including:
pleural space is breached.
• Lung Cancer: Smoking is the
• Air leaks into the pleural space:
leading cause of lung cancer, a
This space, normally filled with a
deadly disease.
small amount of fluid, becomes
• Chronic Obstructive Pulmo-
filled with air.
nary Disease (COPD): This in-
• Lung collapse: The increased air
cludes emphysema and chronic
pressure in the pleural space can
bronchitis, which can make it diffi-
cause the lung to collapse.
cult to breathe.
 • Increased Risk of Infections: or spasm, further narrowing the
Smoking weakens the immune passages.
system, making you more sus- • Wheezing: The narrowing of the
ceptible to respiratory infections airways causes a whistling or
like pneumonia and bronchitis. wheezing sound when you
• Damage to Air Sacs: Cigarette breathe.
smoke destroys the tiny air sacs • Coughing: Your body tries to
(alveoli) in your lungs, reducing clear out the excess mucus and ir-
oxygen intake. ritants through coughing.
• Heart Disease: Smoking in- • Shortness of Breath: As less air
creases your risk of heart attack reaches your lungs, you may ex-
and stroke. perience shortness of breath,
• Other Health Problems: Smok- even with mild activity.
ing has been linked to a variety of
other health problems, including In severe cases, an allergic reaction to
diabetes, erectile dysfunction, the lungs can lead to anaphylaxis, a
and gum disease.. life-threatening condition that can cause
difficulty breathing, swelling of the
15. What happens when the lungs throat, and a drop in blood pressure.
suffers allergic reaction?
16. What influences lung recoil?
When lungs suffer an allergic reac-
tion, it's like a war zone inside the Lung recoil is influenced by two main
body. The immune system, normally a factors:
protector, goes into overdrive, mistak-
• Elasticity: The lungs are made
enly identifying harmless substances as
up of elastic tissue that stretches
invaders. This overreaction leads to a
when you inhale and contracts
cascade of events:
when you exhale. This elasticity
• Inflammation: The airways, or helps the lungs recoil back to their
bronchioles, become inflamed original size after you've taken a
and swollen. This narrows the breath.
passages, making it difficult for air • Surface tension: The inside of
to pass through. the lungs is lined with a thin layer
• Mucus Production: Your body of fluid. This fluid creates a sur-
produces excess mucus to try and face tension that can make it diffi-
flush out the perceived threat. cult for the lungs to expand. How-
This mucus can clog the airways, ever, the body produces a sub-
further hindering breathing. stance called surfactant that
• Muscle Spasms: The muscles helps to reduce surface tension
around the airways may contract, and make it easier for the lungs to
expand.
17. Describe the histological transi- Trachea
tion of the respiratory system from
the nose to the alveoli. • Epithelium: Pseudostratified cili-
ated columnar epithelium with
Nose and Nasal Cavity goblet cells.
• Cartilage: C-shaped rings of hya-
• Epithelium: Pseudostratified cili- line cartilage.
ated columnar epithelium with • Connective Tissue: Submucosa
goblet cells. with blood vessels, nerves, and
• Cartilage: Hyaline cartilage. glands.
• Connective Tissue: Submucosa
with blood vessels, nerves, and Bronchi
glands.
• Epithelium: Pseudostratified cili-
Pharynx (Nasopharynx, Oropharynx, ated columnar epithelium with
Laryngopharynx) goblet cells.
• Cartilage: Plates of hyaline carti-
• Epithelium: Varies: pseudostrati- lage.
fied ciliated columnar in naso- • Connective Tissue: Submucosa
pharynx, stratified squamous in with blood vessels, nerves, and
oropharynx and laryngopharynx. glands.
• Cartilage: None in oropharynx
and laryngopharynx, hyaline carti- Bronchioles
lage in nasopharynx.
• Connective Tissue: Submucosa • Epithelium: Simple columnar ep-
with blood vessels, nerves, and ithelium, then simple cuboidal ep-
glands. ithelium.
• Cartilage: No cartilage.
Larynx • Smooth Muscle: Circular layer of
smooth muscle.
• Epithelium: Stratified squamous
epithelium in vocal folds, pseudo- Terminal Bronchioles
stratified ciliated columnar else-
where. • Epithelium: Simple cuboidal epi-
• Cartilage: Hyaline cartilage (thy- thelium.
roid, cricoid, arytenoid), elastic • No cartilage or glands.
cartilage (epiglottis).
Respiratory Bronchioles
• Connective Tissue: Submucosa
with blood vessels, nerves, and • Epithelium: Simple cuboidal epi-
glands. thelium with alveoli.
• No cartilage or glands.
Alveolar Ducts - Oxygen diffuses from the al-
veoli into the capillaries.
• Epithelium: Simple squamous
epithelium. o Carbon Dioxide Diffu-
• No cartilage or glands. sion:

Alveoli - Carbon dioxide concentra-

tion is higher in the blood
• Epithelium: Simple squamous than in the alveoli.
epithelium. - Carbon dioxide diffuses
• No cartilage or glands. from the capillaries into the
• Gas exchange occurs here. alveoli to be exhaled.
-
The histological structure of the respira-
• Summary
tory system gradually becomes simpler
- The entire process relies on
as you move from the nose to the alve-
simple diffusion, driven by
oli. This transition is necessary for effi-
concentration gradients.
cient gas exchange in the alveoli.
- The thinness of the respira-
18. Describe the path of air as it dif- tory membrane facilitates
fuses across the respiratory mem- efficient gas exchange, es-
brane. sential for maintaining
proper oxygen and carbon
Structure of the Respiratory Mem- dioxide levels in the blood.
brane:
This pathway ensures that oxygen is ef-
• Composed of: fectively absorbed into the bloodstream
- Alveolar epithelium (thin while carbon dioxide is expelled, sup-
layer of cells). porting vital respiratory functions.
- Capillary endothelium
(thin layer of blood vessel 19. Describe how the body ensures
cells). that the food enters the esophagus
- Interstitial space (very thin and air enters the trachea.
area between alveoli and
How the Body Directs Food and Air to
capillaries).
the Right Place:
• Diffusion Process:
• Soft Palate: This soft tissue
o Oxygen Diffusion: closes off the nasal cavity during
swallowing, preventing food or liq-
- Oxygen concentration is uid from entering the nose.
higher in the alveoli than in • Epiglottis: A small flap of carti-
the blood. lage that covers the trachea
(windpipe) during swallowing.
 When you swallow, the epiglottis 21. How can the lung increase and
folds down, closing off the trachea decrease the lung volume and pres-
and directing food into the esoph- sure?
agus.
• Esophagus: A muscular tube The lungs can increase and decrease
that connects the throat to the volume and pressure through:
stomach. It uses peristaltic con-
• Diaphragm contraction: The di-
tractions (wave-like muscle move-
aphragm, a dome-shaped muscle
ments) to push food down toward
below the lungs, flattens down-
the stomach.
ward during inhalation, increasing
• Trachea: The windpipe, which
lung volume and decreasing pres-
carries air to and from the lungs.
sure.
It remains open during swallow-
• Intercostal muscle contraction:
ing, allowing air to pass freely.
These muscles between the ribs
20. Compare and contrast the bron- help expand the chest cavity, also
chial circulation and pulmonary cir- increasing lung volume and de-
culation. creasing pressure.
• Relaxation: During exhalation,
Bronchial Circulation: these muscles relax, decreasing
lung volume and increasing pres-
• Supplies oxygenated blood to the sure, forcing air out.
lung tissues.
• Originates from the aorta. 22. Describe how the blood trans-
• Carries oxygenated blood to the ports gasses throughout the body.
lungs.
• Drains primarily into the pulmo- Blood plays a crucial role in transport-
nary veins. ing gases throughout the body. It car-
ries oxygen from the lungs to the tis-
Pulmonary Circulation:
sues and carbon dioxide from the tis-
• Facilitates gas exchange be- sues back to the lungs for exhalation.
tween blood and lungs.
• Originates from the right ventricle. 1. Oxygen Uptake:
• Carries deoxygenated blood to o Oxygen from the air we breathe enters
the lungs for oxygenation. the lungs and diffuses into the blood-
• Returns oxygenated blood to the stream.
left atrium via pulmonary veins. o Red blood cells, specifically the hemo-

globin molecules within them, bind to

oxygen molecules.
o Oxygen-rich blood is then pumped by

the heart to the body's tissues.

2. Oxygen Delivery: • Bicarbonate ions: Formed from the
o As the blood reaches the tissues, ox- reaction of carbon dioxide with water.
ygen molecules are released from he- • Lungs: Organs where gas exchange
moglobin and diffuse into the cells. takes place.
o These cells use oxygen for cellular • Heart: Pumps blood throughout the
respiration, producing energy. body.

3. Carbon Dioxide Pickup: 23. Describe how the blood is in-

volved in regulation of pH.
o As cells produce carbon dioxide as a

waste product of cellular respiration, it

The blood plays a crucial role in main-
diffuses into the bloodstream. taining the body's pH balance, which is
o Some carbon dioxide is dissolved di- essential for optimal cellular function.
rectly in the blood plasma. This regulation is achieved through a
o A portion of carbon dioxide binds to complex system involving various com-
hemoglobin. ponents:
o Most carbon dioxide is transported
• Bicarbonate buffer system:
as bicarbonate ions, formed by the o The most important buffer
reaction of carbon dioxide with water. system in the blood.
o Consists of carbonic acid

4. Carbon Dioxide Elimination: (H2CO3) and bicarbonate

o Carbon dioxide-laden blood returns to ions (HCO3-).
o Reacts with acids and ba-
the lungs.
ses to neutralize them,
o Carbon dioxide diffuses out of the
maintaining a stable pH.
blood and into the alveoli (air sacs) of o The equilibrium between
the lungs. carbonic acid and bicar-
o The carbon dioxide is then exhaled. bonate ions is influenced by
the enzyme carbonic an-
Key components involved in gas hydrase.
o The lungs and kidneys play
transport:
a significant role in regulat-
• Red blood cells: Contain hemoglobin,
ing the bicarbonate concen-
a protein that binds to oxygen.
tration in the blood.
• Hemoglobin: A protein that binds to o
oxygen molecules. • Protein buffer system:
• Carbon dioxide: A waste product of o Proteins in the blood, such

cellular respiration. as hemoglobin and albu-

min, can act as buffers.
 o The amino acid side chains 25. What is meant by increased or de-
of proteins contain acidic crease in hematocrit value?
and basic groups that can
donate or accept protons, Increased hematocrit means there are
helping to neutralize pH more red blood cells in your blood. This
changes. can happen when your body needs
o more oxygen, like when you're dehy-
• Phosphate buffer system: drated or at a high altitude.
o Less significant than the bi-
Decreased hematocrit means there
carbonate and protein
are fewer red blood cells in your blood.
buffer systems.
This can happen when you're losing
o Involves phosphate ions
blood or if your body isn't making
(HPO42- and H2PO4-).
enough red blood cells.
o Can help neutralize both ac-
ids and bases. 26. Trace the formation of granulo-
cytes and agranulocyte WBC.
24. Describe how the blood is in-
volved in osmosis and water bal- Granulocytes and agranulocytes are
ance. two major types of white blood cells
(WBCs) that play crucial roles in the im-
How Blood Helps:
mune system. They are produced in the
1. Water Delivery: Blood carries bone marrow through a process called
water throughout your body. It hematopoiesis.
picks up water from places like
Formation of Granulocytes
your intestines (after you drink)
and kidneys (which filter waste). 1. Hematopoietic stem cell: The
2. Salt Balance: Blood also carries process begins with a hematopoi-
salt. The balance between water etic stem cell, a multipotent cell
and salt is important. If there's too that can differentiate into various
much salt, water will move to try blood cell lineages.
to balance it out, and vice versa. 2. Common myeloid progenitor:
3. Kidneys: The kidneys are like a The hematopoietic stem cell
water and salt filter. They help de- gives rise to a common myeloid
cide how much water and salt to progenitor, which can further dif-
keep in the blood and how much ferentiate into granulocytes, mon-
to release as waste. ocytes, erythrocytes, and plate-
lets.
3. Myeloblast: The common mye-
loid progenitor becomes a myelo-
blast, a committed precursor cell
for granulocytes.
 4. Promyelocyte: The myeloblast 6. Lymphoid progenitor: Another
matures into a promyelocyte, portion of the common myeloid
characterized by the presence of progenitor differentiates into a
primary granules containing lyso- lymphoid progenitor, which can
somal enzymes. give rise to lymphocytes.
5. Myelocyte: The promyelocyte dif- 7. Common lymphoid progenitor:
ferentiates into a myelocyte, The lymphoid progenitor be-
which acquires secondary gran- comes a common lymphoid pro-
ules specific to each type of gran- genitor.
ulocyte. 8. B cell, T cell, or natural killer
6. Metamyelocyte: The myelocyte cell: The common lymphoid pro-
becomes a metamyelocyte, with a genitor can further differentiate
slightly indented nucleus. into B cells, T cells, or natural
7. Band cell: The metamyelocyte killer cells, which are the three
develops into a band cell, with a major types of lymphocytes.
horseshoe-shaped nucleus.
8. Mature granulocyte: Finally, the Granulocyte formation:
band cell matures into a mature
• Hematopoietic stem cell -> Com-
granulocyte, which can be one of
mon myeloid progenitor -> Myelo-
three types: neutrophils, eosino-
blast -> Promyelocyte -> Myelo-
phils, or basophils.
cyte -> Metamyelocyte -> Band
Formation of Agranulocytes cell -> Mature granulocyte (neu-
trophil, eosinophil, or basophil)
1. Hematopoietic stem cell: The
process begins with a hematopoi- Agranulocyte formation:
etic stem cell, as in the case of
• Hematopoietic stem cell -> Com-
granulocytes.
mon myeloid progenitor -> Mono-
2. Common myeloid progenitor:
blast -> Promonocyte -> Mono-
The hematopoietic stem cell gives
cyte -> Macrophage
rise to a common myeloid progen-
• Hematopoietic stem cell -> Com-
itor.
mon myeloid progenitor -> Lym-
3. Monoblast: A portion of the com-
phoid progenitor -> Common lym-
mon myeloid progenitor differenti-
phoid progenitor -> B cell, T cell,
ates into a monoblast, a precursor
or natural killer cell
cell for monocytes.
4. Promonocyte: The monoblast
matures into a promonocyte.
5. Monocyte: The promonocyte de-
velops into a mature monocyte,
which can migrate into tissues
and become macrophages.
27. What are the functions of each antibodies that bind to antigens
types of WBC cells? on the surface of pathogens, neu-
tralizing them or marking them for
WBC Functions: destruction by other immune
cells.
• Neutrophils: First responders,
• Key players: Antibodies, comple-
kill bacteria and fungi.
ment system, macrophages
• Eosinophils: Fight parasites, in-
volved in inflammatory responses Cellular Immunity
to allergies.
• Basophils: Releases histamine • Mediated by: T cells
and heparin to improve blood flow • Primary target: Intracellular
and prevent blood clots. pathogens (viruses inside cells),
• Monocytes: Become macro- cancer cells
phages, eat debris and invaders. • Mechanism: T cells recognize
• Lymphocytes: antigens presented on the surface
o T cells: Attack infected of infected cells or cancer cells.
cells, cancer cells. Cytotoxic T cells directly kill in-
o B cells: Produce antibodies fected cells, while helper T cells
against invaders. coordinate the immune response
o Natural killer cells: Kill vi- by stimulating other immune cells.
rus-infected and cancer • Key players: T cells (helper, cy-
cells. totoxic), macrophages, natural
killer cells

28. Compare and contrast the hu- Comparison Table

moral and cellular responses.
Feature Humoral Im- Cellular Im-
Both humoral and cellular immunity are munity munity
components of the adaptive immune Medi- B cells T cells
system, designed to provide specific re- ated by
sponses to foreign invaders. While they Primary ExtracellularIntracellular
work together to defend the body, they target pathogens pathogens,
have distinct mechanisms and targets. cancer cells
Mecha- Antibody pro- Direct cell kill-
Humoral Immunity nism duction ing, immune
cell coordina-
• Mediated by: B cells
tion
• Primary target: Extracellular
Key Antibodies, T cells, macro-
pathogens (bacteria, viruses out-
players complement phages, natu-
side cells)
system, mac- ral killer cells
• Mechanism: B cells differentiate
rophages
into plasma cells, which produce
Synergy Natural Active Immunity:

While these two branches of immunity • Acquired through natural expo-

have distinct functions, they often work sure
together. For example, antibodies can • Body produces its own antibodies
neutralize a virus outside a cell, pre- • Long-lasting
venting infection. If the virus does infect • Example: Contracting measles
a cell, the immune system will use cel-
lular immunity to eliminate the infected Natural Passive Immunity:
cell.
• Received from another person
In summary, both humoral and cellular (e.g., mother)
immunity are essential for a robust im- • Pre-formed antibodies transferred
mune response, each playing a vital • Temporary
role in protecting the body from a wide • Example: Breast milk
range of threats.
Artificial Active Immunity:
Humoral and cellular immunity are two
• Obtained through vaccination
branches of the adaptive immune sys-
• Body produces its own antibodies
tem working together.
• Long-lasting
- Humoral immunity uses B cells to cre- • Example: Polio vaccine
ate antibodies that neutralize patho-
Artificial Passive Immunity:
gens outside cells. Think of it as a tar-
geted missile strike. • Received through pre-formed an-
tibodies
- Cellular immunity uses T cells to di-
• Provides immediate protection
rectly attack infected cells or help other
• Temporary
immune cells do so. This is like a
• Example: Rabies immunoglobulin
ground war against invaders inside
cells. 30. Why is the first encounter of an
antigen end up having the patient ac-
quiring the disease?
Both are essential for complete protec-
The first encounter with an antigen of-
tion. Humoral immunity excels against
ten leads to disease because:
extracellular threats, while cellular im-
munity tackles intracellular ones. • The immune system hasn't yet
learned to recognize and fight
29.Compare and contrast Natural Ac-
it. It takes time for the body to pro-
tive, Natural Passive, Artificial Active
duce enough antibodies to neu-
and Artificial passive immunity.
tralize the antigen and prevent the
disease.
 • Think of it like meeting a new 1. Renin Release: When blood
person. The first time you meet pressure or blood flow to the kid-
them, you might not know much neys decreases, the kidneys re-
about them, and they might not lease an enzyme called renin into
know much about you. But over the bloodstream.
time, as you get to know each 2. Angiotensin I Formation: Renin
other better, you learn their acts on a protein called angioten-
strengths and weaknesses, and sinogen, converting it into angio-
you can better anticipate their ac- tensin I.
tions. 3. Angiotensin II Formation: Angi-
• In the same way, the immune otensin I is then converted into
system needs time to learn angiotensin II by an enzyme
about an antigen and develop called angiotensin-converting en-
the tools to fight it. zyme (ACE).
4. Blood Pressure Increase: Angi-
31. What makes the Erythrocyte ef- otensin II is a powerful vasocon-
fective in performing its function? strictor, meaning it causes blood
vessels to narrow, increasing
Erythrocytes, or red blood cells, are
blood pressure.
effective at transporting oxygen and
5. Aldosterone Release: Angioten-
carbon dioxide throughout the body due
sin II also stimulates the release
to their unique shape and composi-
of aldosterone from the adrenal
tion. Their biconcave shape increases
glands.
surface area, allowing for efficient gas
6. Sodium and Water Retention:
exchange. Additionally, the presence of
Aldosterone promotes sodium
hemoglobin, a protein containing iron,
and water retention in the kid-
enables them to bind to oxygen mole-
neys, leading to an increase in
cules and transport them to tissues.
blood volume and further raising
32. Describe the Renin-Angiotensin- blood pressure.
Aldosterone System.
In essence, the RAAS system helps
The Renin-Angiotensin-Aldosterone maintain blood pressure by responding
System (RAAS) is a hormonal system to changes in blood volume and flow.
involved in regulating blood pressure It's a critical part of the body's homeo-
and fluid balance in the body. It's a com- static mechanisms.
plex chain of events that starts in the
33. Describe the degradation of
kidneys and involves several hormones
erythrocytes.
and organs.
Erythrocytes, or red blood cells, have a
Here's an overview:
lifespan of approximately 120 days. As
they age, they undergo various
changes that make them less efficient ▪ Bilirubin is ex-
at carrying oxygen. Eventually, they are creted by the
recognized as "worn out" and are re- liver in bile.
moved from circulation by specialized
cells called macrophages. This process ensures that the body has
a constant supply of healthy, functional
Here's a breakdown of the degrada- red blood cells to transport oxygen
tion process: throughout the body.

1. Senescence: As erythrocytes 34. Trace the events in clotting cas-

age, their membranes become cade.
less flexible and their hemoglobin
begins to degrade. This makes it The clotting cascade, also known as the
harder for them to pass through coagulation cascade, is a series of bi-
narrow capillaries and to effi- ochemical reactions that ultimately lead
ciently bind and release oxygen. to the formation of a blood clot. This pro-
2. Recognition and Phagocytosis: cess is essential to prevent excessive
Macrophages, primarily located in bleeding after an injury.
the spleen, liver, and bone mar-
There are three main pathways in-
row, recognize senescent eryth-
volved in the clotting cascade: the intrin-
rocytes based on changes in their
sic pathway, the extrinsic pathway, and
surface proteins. They engulf and
the common pathway.
destroy these cells.
3. Breakdown of Components: Intrinsic Pathway:
o Hemoglobin: The hemo-
globin is broken down into 1. Initiation: This pathway is trig-
its two main components: gered by substances within the
globin and heme. blood itself, such as contact with
▪ The globin protein is a foreign surface or damaged
further degraded into blood vessel.
amino acids, which 2. Activation: A cascade of reac-
can be recycled by tions occurs, involving several
the body. clotting factors (numbered I-XIII).
▪ The heme group is The key steps include the activa-
broken down into iron tion of factor XII and the formation
and bilirubin. of factor XIa.
▪ The iron is recy- 3. Common Pathway: The intrinsic
cled to be used pathway converges with the com-
in the produc- mon pathway at the activation of
tion of new red factor X.
blood cells.
Extrinsic Pathway:
 1. Initiation: This pathway is trig- • The clotting cascade is tightly reg-
gered by tissue factor, a protein ulated to prevent excessive clot-
released from damaged tissue ting.
cells.
2. Activation: Tissue factor binds to 35. Trace the events in clot dissolu-
factor VII, activating it. Activated tion.
factor VIIa then activates factor X.
Clot dissolution, or fibrinolysis, is a
3. Common Pathway: The extrinsic
critical process in maintaining blood
pathway also converges with the
flow. It involves the breakdown of blood
common pathway at the activation
clots after they've served their purpose
of factor X.
of stopping bleeding. Here's a break-
Common Pathway: down of the key events involved:

1. Activation: Factor X is activated 1. Activation of Plasminogen

by either the intrinsic or extrinsic • Tissue Plasminogen Activator (tPA):
pathway. This enzyme, released from the endo-
2. Thrombin Formation: Activated thelium of blood vessels, binds to fibrin
factor X, along with factor V, acti- in the clot.
vates prothrombin (factor II) to • Urokinase-type Plasminogen Activa-
form thrombin. tor (uPA): Released from cells like en-
3. Fibrin Formation: Thrombin con- dothelial cells and macrophages, it also
verts fibrinogen (factor I) into fi- activates plasminogen.
brin, which forms a mesh-like net- • Plasminogen: This inactive protein is
work that traps blood cells and converted into plasmin, the enzyme re-
platelets to form a clot. sponsible for clot dissolution.
4. Clot Stabilization: Factor XIIIa
cross-links fibrin, strengthening 2. Plasmin-Mediated Fibrinolysis
the clot and making it more stable. • Fibrin Degradation: Plasmin breaks
down the fibrin strands that form the
Key Points: clot's network.
• Fibrin Degradation Products (FDPs):
• The clotting cascade is a complex The breakdown products of fibrin are
process involving multiple clotting cleared from the bloodstream.
factors and pathways.
• The intrinsic and extrinsic path- 3. Clot Retraction
ways are separate but con- • Platelet Contraction: Platelets within
verge at the common pathway. the clot contract, pulling the edges of
• The common pathway leads to the injured vessel closer together.
the formation of thrombin and • Reduced Clot Size: This contraction
fibrin, which are essential for clot helps to reduce the overall size of the
formation. clot.
 more specialized for making red blood
4. Regulation of Fibrinolysis cells.
• Inhibitors: To prevent excessive clot • Burst-forming unit-erythroid (BFU-
dissolution, the body has natural inhibi- E): This cell is a precursor to red blood
tors like plasminogen activator inhib- cells.
itor-1 (PAI-1) and alpha-2-antiplas- • Colony-forming unit-erythroid (CFU-
min. E): This is another precursor, more
• Balance: The balance between clot committed to becoming a red blood cell.
formation and dissolution is crucial for • Proerythroblast: This is the first cell
maintaining healthy blood flow. that looks like a red blood cell.
• Basophilic erythroblast (BE): This
Key Points: cell has a blue color due to its ribo-
• Clot dissolution is a tightly regulated somes.
process. • Polychromatophilic erythroblast
• Plasmin is the primary enzyme respon- (PE): This cell has both blue and red
sible for breaking down fibrin. colors as it starts to make hemoglobin.
• Tissue plasminogen activator (tPA) • Orthochromatophilic erythroblast
and urokinase-type plasminogen ac- (OE): This cell is mostly red as it contin-
tivator (uPA) play important roles in ac- ues to make hemoglobin.
tivating plasmin. • Reticulocyte (RET): This cell has lost
• The body has mechanisms in place to its nucleus but still has some extra
prevent excessive clot dissolution. parts.
• Mature red blood cell (RBC): This is
Note: The specific details of clot disso- the final stage, a fully developed red
lution can vary depending on the type of blood cell ready to carry oxygen.
clot and the underlying cause. The whole process is controlled by a
hormone called erythropoietin (EPO),
36. Trace the events during erythro- which is made by the kidneys.
poiesis.
37. What are the nutrients needed in
Erythropoiesis is the process of mak- erythrocyte development and ma-
ing red blood cells (RBCs). Here's a turity?
breakdown of the stages:
• Iron: The primary component of
• Hematopoietic stem cell (HSC): This hemoglobin, a protein that carries
is the starting point, a versatile cell that oxygen in red blood cells.
can become many different types of • Vitamin B12: Essential for DNA
blood cells. synthesis and the formation of red
• Common myeloid progenitor (CMP): blood cells.
The stem cell becomes this, which is
 • Folate: Another B vitamin crucial o Regulatory T cells: These cells help
for DNA synthesis and red blood regulate the immune response and pre-
cell production. vent excessive inflammation.
• Copper: Helps in the absorption
and utilization of iron. In summary, T-cells play a vital role in
• Protein: Needed for the synthesis cellular immunity by recognizing in-
of hemoglobin and other proteins fected cells, activating immune re-
in red blood cells. sponses, and directly killing infected
cells or helping other immune cells do
38. Discuss the function of the cells so.
in Cellular Immunity (T-Cells).
39. Describe the function of antibod-
ies.
Functions of T-cells in Cellular Immunity

T-cells, or T lymphocytes, are crucial Antibodies, also known as immuno-

players in the immune system, particu- globulins, are Y-shaped proteins pro-
larly in cellular immunity. They are re- duced by the immune system to fight off
sponsible for recognizing and attacking foreign invaders. Their primary func-
cells infected with viruses, bacteria, or tions include:
other pathogens.
• Neutralization: Antibodies bind
Primary functions of T-cells: to antigens (foreign substances)
on pathogens, neutralizing their
• Recognition of infected cells: T-cells toxic effects.
have receptors that can recognize spe- • Opsonization: Antibodies coat
cific antigens (foreign substances) pre- pathogens, making them more at-
sented on the surface of infected cells. tractive to phagocytes (cells that
• Activation: When a T-cell encounters engulf and destroy foreign in-
its specific antigen, it becomes acti- vaders).
vated and begins to divide and differen- • Complement Activation: Anti-
tiate into effector cells. bodies activate the complement
• Effector functions: Activated T-cells system, a group of proteins that
can perform various effector functions help to destroy pathogens and
to eliminate infected cells: promote inflammation.
o Cytotoxic T cells (CD8+ T cells): • Agglutination: Antibodies can
These cells directly kill infected cells by clump together pathogens, mak-
releasing toxic substances. ing it easier for phagocytes to en-
o Helper T cells (CD4+ T cells): These gulf them.
cells help activate other immune cells, • Immune Complex Formation:
such as B cells and macrophages, to Antibodies can form immune
fight the infection. complexes with antigens, which
 can be removed from the body by oAggregation: More plate-
the immune system. lets gather, forming a tem-
porary plug to seal the
40. Describe the formation of throm- breach.
bocytes. 3. Coagulation:
o Clot formation: A complex
Thrombocytes, or platelets, are
series of chemical reactions
formed in the bone marrow through a
leads to the formation of a
process called thrombopoiesis.
blood clot, which reinforces
1. Stem cells in the bone marrow the platelet plug.
differentiate into megakaryo- o Fibrin: A protein called fi-

cytes, which are large cells. brin forms a network that

2. Megakaryocytes develop a net- traps blood cells and plate-
work of cytoplasmic extensions lets, solidifying the clot.
called proplatelets.
42. Describe the histological anat-
3. These proplatelets break off into
omy of the different heart layers.
smaller fragments, which become
platelets. Epicardium
Platelets are essential for blood clotting • Outermost layer of the heart
and wound healing. • Visceral layer of the serous peri-
cardium
41. Discuss the three phases in the
• Composed of mesothelial cells
stoppage of bleeding.
and connective tissue
Hemostasis, the process of stopping • Contains blood vessels and
bleeding, occurs in three main phases: nerves that supply the heart

1. Vascular Spasm: Myocardium

o Immediate reaction: Blood
• Middle layer of the heart
vessels constrict (narrow) to
• Thickest layer, composed primar-
reduce blood flow.
ily of cardiac muscle tissue
o Temporary measure: It
• Responsible for the heart's pump-
helps slow bleeding while
ing action
other mechanisms take ef-
• Contains the conducting system
fect.
(SA node, AV node, bundle of His,
2. Platelet Plug Formation:
Purkinje fibers)
o Adhesion: Platelets stick to
the damaged blood vessel Endocardium
wall.
• Innermost layer of the heart
• Lines the chambers and valves
 • Composed of endothelium, sub- In simpler terms, inotropy is about how
endothelial connective tissue, and hard the heart pumps, while chrono-
a thin layer of smooth muscle tropy is about how fast it pumps.
• Contains the Purkinje fibers (part
of the conducting system) 45. What happens to the heart cham-
bers during systole and diastole.
43. What are the blood vessels sup-
plying the heart muscle? Systole:
• Heart chambers contract: The atria
The heart muscle is supplied by the cor- (upper chambers) and ventricles (lower
onary arteries. These arteries branch chambers) squeeze together.
from the aorta and wrap around the • Blood is pumped out: The atria push
heart, delivering oxygen-rich blood to blood into the ventricles, and the ventri-
the heart muscle. There are two main cles pump blood out of the heart.
coronary arteries:
Diastole:
• Left coronary artery: Supplies
• Heart chambers relax: The atria and
blood to the left ventricle, the left
ventricles relax.
atrium, and part of the septum.
• Chambers fill with blood: The atria fill
• Right coronary artery: Supplies
with blood from the body, and the ven-
blood to the right ventricle, the
tricles fill with blood from the atria.
right atrium, and part of the sep-
tum.
46. What happens to the heart valves
44. Compare inotropy and chrono-
during systole and diastole?
tropy.
During systole:
Inotropy and chronotropy are two
terms related to the heart's function. • The heart contracts to pump
blood out of the heart.
• Inotropy refers to the force of the
• The atrioventricular (AV) valves
heart's contractions. A positive
(mitral and tricuspid) close to pre-
inotropic effect increases the
vent blood from flowing backward
strength of contractions, while a
into the atria.
negative inotropic effect de-
• The semilunar valves (aortic and
creases it.
pulmonary) open to allow blood to
• Chronotropy refers to the heart
flow into the aorta and pulmonary
rate. A positive chronotropic ef-
artery.
fect increases the heart rate,
while a negative chronotropic During diastole:
effect decreases it.
• The heart relaxes to fill with blood.
 • The semilunar valves close to 48. Trace the flow of blood from the
prevent blood from flowing back vena cava to the aorta.
into the ventricles.
• The AV valves open to allow 1. Superior Vena Cava (SVC) and
blood to flow from the atria into Inferior Vena Cava (IVC) bring
the ventricles. deoxygenated blood from the
body back to the heart.
47. What happens to the heart during 2. Right Atrium: Blood enters the
a heart attack? right atrium from the SVC and
IVC.
During a heart attack, the heart's
3. Tricuspid Valve: Blood passes
blood supply is blocked. This usually
through the tricuspid valve into
happens when a coronary artery,
the right ventricle.
which supplies blood to the heart mus-
4. Pulmonary Valve: The right ven-
cle, becomes narrowed or blocked by a
tricle contracts, pushing blood
blood clot.
through the pulmonary valve and
Without sufficient blood flow, the heart into the pulmonary arteries.
muscle begins to die. This is called my- 5. Lungs: Pulmonary arteries carry

ocardial infarction. The amount of deoxygenated blood to the lungs

heart muscle damage depends on the for oxygenation.
location and duration of the blockage. 6. Pulmonary Veins: Oxygenated
blood from the lungs returns to the
Key consequences of a heart attack heart through the pulmonary
include: veins.
7. Left Atrium: Oxygenated blood
• Heart muscle damage: The af- enters the left atrium from the pul-
fected area of the heart muscle monary veins.
may become scarred, reducing its 8. Mitral Valve: Blood passes
ability to pump blood effectively. through the mitral valve into the
• Arrhythmias: Irregular heart left ventricle.
rhythms can occur due to damage 9. Aortic Valve: The left ventricle
to the electrical system of the contracts, pushing oxygenated
heart. blood through the aortic valve and
• Heart failure: In severe cases, a into the aorta.
heart attack can lead to heart fail- 10. Body: The aorta distributes oxy-
ure, where the heart is unable to genated blood to the rest of the
pump enough blood to meet the body.
body's needs.
• Sudden cardiac death: If the 49. Trace the normal electrical flow of
heart attack is not treated the heart (Conduction system).
promptly, it can be fatal.
 The normal electrical flow of o The Bundle of His divides
the heart, or the conduction into the left and right bundle
system, ensures a coordinated branches, which descend
contraction of the heart cham- along the interventricular
bers. This system consists of spe- septum.
cialized cardiac muscle cells that 6. Purkinje Fibers:
generate and transmit electrical o The bundle branches termi-
impulses. nate in the Purkinje fibers,
which spread throughout
Step-by-step breakdown of the nor- the ventricular walls.
mal electrical flow: 7. Ventricular Contraction:
1. Sinoatrial (SA) Node: o The Purkinje fibers distrib-
o The SA node, located in the
ute the electrical impulse to
right atrial wall near the su- the ventricular muscle cells,
perior vena cava, is the causing them to contract
heart's natural pacemaker. and pump blood out of the
o It generates electrical im-
heart.
pulses at a regular rate. Visual Representation:
2. Atrial Contraction: SA node → Atrial walls → AV node →
o The electrical impulse Bundle of His → Left and Right Bundle
spreads across the atrial Branches → Purkinje fibers → Ventric-
walls, causing them to con- ular walls
tract and push blood into the
ventricles. 50. Describe the events in the normal
3. Atrioventricular (AV) Node: ElectroCardiogram (ECG) reading.
o The electrical impulse
reaches the AV node, lo- An ECG measures the electrical activity
cated in the interatrial sep- of your heart. A normal ECG shows the
tum near the tricuspid valve. following:
o The AV node delays the im-
• P wave: This is the first wave. It repre-
pulse, allowing the atria to
sents the electrical activity of the atria
finish contracting before the
(the upper chambers of the heart) as
ventricles begin.
they contract.
4. Bundle of His:
• PR interval: This is the interval be-
o The impulse travels down
tween the end of the P wave and the be-
the Bundle of His, a group of
ginning of the QRS complex. It repre-
specialized cardiac muscle
sents the time it takes for the electrical
fibers located in the inter-
impulse to travel from the atria to the
ventricular septum.
ventricles.
5. Left and Right Bundle
Branches:
• QRS complex: This is a group of three o Low MAP: Can lead to tis-
waves. It represents the electrical activ- sue hypoxia and organ dys-
ity of the ventricles (the lower chambers function.
of the heart) as they contract. o High MAP: Can increase
• ST segment: This is the flat line be- the risk of cardiovascular
tween the end of the QRS complex and events.
the beginning of the T wave. It repre-
sents the time between the end of ven- 52. Describe the intrinsic regulation
tricular contraction and the beginning of of the heart.
ventricular recovery. Intrinsic regulation refers to the
• T wave: This is the last wave. It repre-
heart's ability to adjust its own pumping
sents the electrical activity of the ventri-
activity in response to changes in
cles as they recover from contraction.
• QT interval: This is the interval be- blood volume returning to it. This
tween the beginning of the QRS com- mechanism is primarily governed by
plex and the end of the T wave. It rep- the Frank-Starling law.
resents the total time it takes for the
heart to contract and recover.
The Frank-Starling Law states that
51. Discuss the Mean Arterial Pres- the force of contraction of the heart
sure. muscle is directly proportional to the
degree of stretch of the heart muscle fi-
• Definition: MAP is the average
bers. In simpler terms, the more
pressure in the arteries through-
blood that fills the heart chambers
out one cardiac cycle.
(preload), the more forcefully the
• Importance: It's a crucial indica-
heart will contract.
tor of tissue perfusion and organ
function. Key points to remember about the
• Factors Affecting MAP:
Frank-Starling mechanism:
o Cardiac output: The
• Preload: This refers to the amount of
amount of blood pumped by
the heart per minute. blood in the heart chambers at the end
o Systemic vascular re- of diastole (filling phase).
sistance: The resistance of • Afterload: This refers to the resistance
blood vessels to blood flow. the heart must overcome to eject
• Calculation: blood.
o MAP = (2 x diastolic blood
• Cardiac output: This is the amount of
pressure) + systolic blood
blood pumped by the heart per minute.
pressure / 3
• Normal Range: 70-110 mmHg
• Clinical Significance: How the Frank-Starling mechanism
works:
1. Increased venous return: When more
53. Describe the extrinsic regulation
blood returns to the heart, the heart
of the heart.
chambers stretch.
2. Increased preload: The increased Extrinsic regulation of the heart refers
stretch of the heart muscle fibers leads to the control of its function by factors
to increased preload. outside the heart itself. These factors
3. Increased contractility: The heart primarily involve the nervous system
and hormonal influences.
muscle responds to the increased
stretch by contracting more forcefully. Nervous System Regulation
4. Increased cardiac output: The in-
creased contractility leads to increased • Sympathetic Nervous System:
This system is activated during
cardiac output, ensuring that the heart
stress, exercise, or excitement. It
pumps out the same amount of blood
sends signals to the heart, caus-
that flows into it. ing it to:
o Increase heart rate: This
Importance of the Frank-Starling means the heart beats
mechanism: faster.
o Increase stroke volume:
• Maintains cardiac output: The Frank-
This means the heart
Starling mechanism helps to maintain
pumps more blood per beat.
a constant cardiac output, even when
o Increase cardiac output:
there are fluctuations in blood volume. This means the heart
• Adapts to changing demands: It al- pumps more blood overall.
lows the heart to adapt to changes in • Parasympathetic Nervous Sys-
metabolic needs, such as during exer- tem: This system is active during
cise or stress. rest and relaxation. It sends sig-
• Prevents heart failure: By ensuring nals to the heart, causing it to:
o Decrease heart rate: This
that the heart pumps out all the blood
means the heart beats
that returns to it, the Frank-Starling slower.
mechanism helps to prevent heart fail- o Decrease stroke volume:
ure. This means the heart
In conclusion, the intrinsic regulation pumps less blood per beat.
of the heart, as exemplified by the o Decrease cardiac output:

Frank-Starling law, is a vital mecha- This means the heart

pumps less blood overall.
nism that allows the heart to adjust its
pumping activity to meet the body's Hormonal Regulation
changing needs.
 • Adrenaline (Epinephrine): This
hormone is released by the ad- Parasympathetic Response:
renal glands during stress or ex- • Decreases heart rate: Slows the sino-
citement. It has a similar effect to atrial node, causing slower heartbeats.
the sympathetic nervous system, • Decreases heart contractility: Re-
causing the heart to beat faster duces the force of heart contractions.
and stronger. • Decreases cardiac output: De-
• Thyroid Hormones: These hor- creases the amount of blood pumped
mones regulate metabolism and by the heart per minute.
can also influence heart rate. High • Narrows blood vessels: Constricts
levels of thyroid hormone can in- blood vessels in the heart, digestive
crease heart rate, while low levels system, and other organs.
can decrease it.
Together, these two systems help main-
In summary, the extrinsic regulation of tain a balanced heart rate and blood
the heart ensures that it can adapt to pressure, adapting to the body's needs
changing demands on the body. in different situations.
Whether it's responding to a sudden
burst of activity or maintaining a steady 55. What is the influence of pH, CO2
rhythm during sleep, the nervous sys- and oxygen to cardiac activity?
tem and hormones work together to
pH, CO2, and oxygen play crucial roles
keep the heart functioning optimally.
in regulating cardiac activity. These fac-
54. What is the effect of the sympa- tors are closely interconnected and can
thetic and parasympathetic re- significantly impact the heart's rate,
sponse to the heart? force of contraction, and overall func-
The sympathetic and parasympathetic tion.
nervous systems have opposing effects
1. pH (Acidity or Alkalinity)
on the heart:
• Acidosis (low pH):
Sympathetic Response:
o Increases heart rate and
• Increases heart rate: Stimulates the
force of contraction.
sinoatrial node, causing faster heart-
o This is a compensatory re-
beats.
sponse to improve oxygen
• Increases heart contractility: In-
delivery to tissues.
creases the force of heart contractions.
o Prolonged acidosis can
• Increases cardiac output: Increases
lead to cardiac arrhythmias
the amount of blood pumped by the
and metabolic stress.
heart per minute.
• Alkalosis (high pH):
• Widens blood vessels: Dilates blood
o Decreases heart rate and
vessels in the heart and skeletal mus-
force of contraction.
cles to increase blood flow.
 o This is a protective mecha- o While not as commonly en-
nism to prevent excessive countered, excessive oxy-
oxygen delivery. gen can be harmful, espe-
o Severe alkalosis can lead to cially in certain conditions
muscle weakness and neu- like acute respiratory dis-
rological problems. tress syndrome (ARDS).

2. CO2 (Carbon Dioxide) In summary, the heart is highly sensi-

tive to changes in pH, CO2, and oxygen
• Increased CO2 (hypercapnia): levels. These factors work together to
o Stimulates the respiratory maintain optimal cardiac function and
center in the brain, leading ensure adequate oxygen delivery to the
to increased breathing rate. body's tissues. Imbalances in any of
o This increased ventilation these factors can lead to various cardi-
helps to eliminate excess ovascular problems and require prompt
CO2 and improve blood pH. medical attention.
o If CO2 levels rise signifi-
cantly, it can also directly 56. What are the factors that influ-
stimulate the heart, increas- ence increase or decrease in blood
ing heart rate and force of pressure?
contraction.
• Decreased CO2 (hypocapnia): Blood pressure is a measure of the
o Can lead to a decrease in force exerted by the blood against the
heart rate and force of con- walls of your arteries. Many factors can
traction. influence both increases and de-
o This is often associated with
creases in blood pressure. Here's a
hyperventilation, which can
breakdown:
cause a decrease in blood
CO2 levels. Factors That Increase Blood Pressure
3. Oxygen (O2)
• Lifestyle Factors:
• Decreased oxygen (hypoxia): o Diet: High sodium intake, excessive
o Triggers an increase in consumption of saturated and trans
heart rate and force of con- fats, and a diet low in potassium can
traction to deliver more oxy- elevate blood pressure.
gen to tissues. o Physical Activity: Lack of regular ex-
o Prolonged hypoxia can lead
ercise can contribute to high blood
to tissue damage and car-
pressure.
diac dysfunction.
• Increased oxygen (hyperoxia):
o Obesity: Excess weight puts strain on o Healthy Diet: A diet rich in fruits, vege-
the heart and blood vessels, leading to tables, whole grains, and lean proteins
increased blood pressure. can help lower blood pressure.
o Smoking: Nicotine constricts blood o Regular Exercise: Regular physical
vessels, raising blood pressure. activity can improve heart health and
o Alcohol Consumption: Excessive al- lower blood pressure.
cohol intake can damage the heart and o Weight Management: Losing weight
blood vessels. can reduce the strain on your heart
o Stress: Chronic stress can trigger the and blood vessels.
release of hormones that increase o Quitting Smoking: Quitting smoking
blood pressure. can improve blood vessel health and
lower blood pressure.
• Medical Conditions: o Stress Management: Techniques like
o Diabetes: Diabetes can damage blood relaxation exercises, meditation, and
vessels and kidneys, leading to high yoga can help reduce stress and lower
blood pressure. blood pressure.
o Kidney Disease: Impaired kidney • Medications:
function can affect fluid and electrolyte o Antihypertensive Medications: A va-
balance, influencing blood pressure. riety of medications can be used to
o Adrenal Gland Disorders: Conditions lower blood pressure, including diuret-
like Cushing's syndrome and pheo- ics, beta-blockers, ACE inhibitors, an-
chromocytoma can cause high blood giotensin II receptor blockers, and cal-
pressure. cium channel blockers.
o Sleep Apnea: Obstructive sleep apnea
57. Describe the different layers of
can disrupt sleep and increase blood blood vessels.
pressure.
1. Tunica Intima (Inner Layer):
• Medications:
• Directly contacts the blood flowing
o Certain medications: Some medica- through the vessel.
tions, such as oral contraceptives, cor- • Composed of a single layer of en-
ticosteroids, and decongestants, can dothelial cells, a basement mem-
raise blood pressure brane, and a thin layer of connec-
tive tissue.
Factors that Decrease Blood Pressure • Regulates blood flow, prevents
blood clotting, and keeps tox-
ins out of the blood.
• Lifestyle Factors:
 • In arteries, it contains a layer of Arteries, veins, and capillaries are
elastic fibers that helps maintain three primary types of blood vessels in
blood pressure. the circulatory system, each with dis-
tinct functions and characteristics:
2. Tunica Media (Middle Layer):
Arteries
• The thickest layer in arteries,
composed primarily of smooth • Function: Carry blood away from
muscle cells and elastic fibers. the heart to the body's tissues.
• Controls blood vessel diame- • Structure: Thick, muscular walls
ter, regulating blood flow and to withstand the high pressure of
blood pressure. blood pumped from the heart.
• Smooth muscle cells can contract • Blood type: Typically carry oxy-
to narrow the vessel (vasocon- genated blood (except for pulmo-
striction) or relax to widen it (vas- nary arteries).
odilation).
• In veins, this layer is thinner and Veins
contains less smooth muscle.
• Function: Carry blood back to
3. Tunica Externa (Outer Layer): the heart from the body's tissues.
• Structure: Thinner walls than ar-
• Composed of connective tissue, teries, often containing valves to
including collagen and elastic fi- prevent blood from flowing back-
bers. ward.
• Provides structural support • Blood type: Typically carry deox-
and anchors the vessel to sur- ygenated blood (except for pul-
rounding tissues. monary veins).
• Contains nerves and tiny blood
vessels (vasa vasorum) that sup- Capillaries
ply oxygen and nutrients to the
• Function: Connect arteries to
vessel wall.
veins, allowing for the exchange
• In larger veins, it may also con-
of oxygen, nutrients, and waste
tain valves that prevent blood
products between the blood and
from flowing backward.
body cells.
The thickness and composition of these • Structure: Extremely thin walls to
layers vary depending on the type of facilitate the exchange of sub-
blood vessel (artery, vein, or capillary) stances.
and its specific function. • Blood type: Carry both oxygen-
ated and deoxygenated blood,
58. Compare arteries, veins and ca- depending on their location.
pillaries.
Summary Table:
Feature Arteries Veins Capillaries allowing for significant ex-
Func- Carry Carry Facilitate pansion and recoil.
o Tunica adventitia: Outer
tion blood blood exchange
away back to between layer composed of connec-
from the the blood and tive tissue, providing sup-
heart heart cells port and anchoring.
Struc- Thick, Thinner Extremely • Function:
o Dampen pressure pulses:
ture muscu- walls thin walls
lar walls with Absorb the force of the
valves heart's contractions, pre-
Blood Typi- Typi- Both oxy- venting excessive fluctua-
type cally ox- cally de- genated tions in blood pressure.
o Maintain blood flow: Re-
ygen- oxygen- and deoxy-
ated ated genated coil of the elastic tissue
helps to propel blood for-
ward during diastole (when
Note: While the general characteristics the heart is relaxed).
are as described above, there are ex-
ceptions, such as the pulmonary arter- Muscular Arteries
ies and veins, which carry opposite
• Location: Further away from the
types of blood.
heart, distributing blood to specific
59. Compare muscular and elastic ar- organs and tissues.
teries. • Structure:
o Tunica intima: Thicker
Muscular and elastic arteries are both than in elastic arteries.
types of blood vessels that carry oxy- o Tunica media: Contains a

genated blood away from the heart. thicker layer of smooth mus-
They differ primarily in their structure cle, allowing for vasocon-
and function, reflecting their specific striction and vasodilation.
roles in the circulatory system. o Tunica adventitia: Outer
layer composed of connec-
Elastic Arteries tive tissue, providing sup-
port and anchoring.
• Location: Closer to the heart,
• Function:
such as the aorta and pulmonary
o Regulate blood flow: Can
artery.
constrict or dilate to control
• Structure:
the amount of blood deliv-
o Tunica intima: Relatively
ered to specific organs.
thin.
o Maintain blood pressure:
o Tunica media: Contains a
Help to maintain a relatively
thick layer of elastic tissue,
 constant blood pressure in Balance:
the peripheral circulation.
The sympathetic and parasympathetic
In summary, elastic arteries are de- nervous systems work together to main-
signed to accommodate the high pres- tain a balance in the body's blood pres-
sure and pulsatile flow of blood from the sure and circulation. The sympathetic
heart, while muscular arteries are response is activated during stress or
more concerned with regulating blood emergencies, while the parasympa-
flow to specific organs and maintaining thetic response dominates during rest
a consistent blood pressure. Both types and digestion.
of arteries have a tunica adventitia,
which provides structural support and 61. What are the blood supplies and
anchoring. drains of the brain and heart?

60. What is the effect of sympathetic Brain

and parasympathetic response to
Supply:
the blood vessels?
• Internal carotid arteries: Supply
Sympathetic Response:
the anterior and middle parts of
• Vasoconstriction: Causes blood the brain.
vessels to narrow, reducing blood • Vertebral arteries: Supply the
flow. This increases blood pres- posterior part of the brain, includ-
sure and redirects blood to vital ing the brainstem and cerebellum.
organs like the heart and brain.
Drainage:
• Increased heart rate: The sym-
pathetic nervous system also in- • Dural sinuses: These large veins
creases heart rate, further contrib- collect blood from the brain and
uting to increased blood pressure. drain it into the internal jugular
veins.
Parasympathetic Response:
Heart
• Vasodilation: Causes blood ves-
sels to widen, increasing blood Supply:
flow. This lowers blood pressure
and promotes digestion and relax- • Coronary arteries: These arter-
ation. ies branch off the aorta and sup-
• Decreased heart rate: The para- ply oxygenated blood to the heart
sympathetic nervous system muscle.
slows down the heart rate, con-
tributing to a decrease in blood Drainage:
pressure.
 • Coronary sinus: This large vein 9. Tibial and Fibular Arteries: The
collects deoxygenated blood from popliteal arteries divide into the tibial
the heart muscle and returns it to and fibular arteries, which supply blood
the right atrium. to the lower leg and foot.

62. Trace the flow of blood from the 10. Arterioles and Capillaries: The ar-
brain to the toes. teries branch into smaller and smaller
vessels, eventually becoming arterioles
1. Brain: Blood is initially oxygenated in
and then capillaries. These tiny vessels
the lungs and returns to the heart's left
deliver oxygen and nutrients to the tis-
atrium. From there, it's pumped into the
sues of the toes.
left ventricle and then out through the
11. Venules and Veins: After deliver-
aorta.
ing oxygen and nutrients, the blood col-
2. Descending Aorta: The aorta, the
lects in venules, which merge to form
body's largest artery, descends down-
veins. These veins carry deoxygenated
wards through the chest and abdomen.
blood back to the heart.

3. Abdominal Aorta: As the aorta con-

12. Inferior Vena Cava: The veins from
tinues, it becomes the abdominal aorta.
the lower body eventually join to form
This artery supplies blood to the organs
the inferior vena cava, which carries de-
in the abdomen.
oxygenated blood back to the heart's
right atrium.
4. Common Iliac Arteries: The ab-
dominal aorta divides into the common This cycle repeats continuously, ensur-
iliac arteries, one on each side of the ing that the toes receive a constant sup-
body. ply of oxygenated blood and nutrients.

5. Internal Iliac Arteries: These arter- 63. Trace the flow of blood from the
ies supply blood to the pelvic organs right thumb to the left thumb.
and buttocks.
1. Right Thumb: Blood enters the
right thumb through the princeps
6. External Iliac Arteries: These arter-
pollicis artery, a branch of the
ies supply blood to the legs.
deep palmar arch.

7. Femoral Arteries: The external iliac 2. Deep Palmar Arch: This arch is
arteries become the femoral arteries as a network of arteries located in
they enter the thigh. the palm of the hand. It receives
blood from the radial artery and
8. Popliteal Arteries: Behind the knee, ulnar artery.
the femoral arteries become the poplit-
eal arteries. 3. Radial and Ulnar Arteries:
These arteries supply blood to
 the hand and forearm. They orig- 12. Princeps Pollicis Artery
inate from the brachial artery in (Left): This artery supplies blood
the upper arm. to the left thumb.

4. Brachial Artery: This artery is a Essentially, the blood travels

continuation of the axillary ar- through the circulatory system,
tery. passing through the heart, lungs,
and major arteries and veins to reach
the left thumb.
5. Axillary Artery: This artery sup- 64. Trace the flow of blood from the
plies blood to the arm. It is a con- intestines to the kidneys.
tinuation of the subclavian ar-
tery.
1. Intestinal Veins:
6. Subclavian Artery: This artery • Superior Mesenteric Vein
supplies blood to the arm and (SMV): Collects blood from the
shoulder. It originates from the small intestine, part of the large
aortic arch.
intestine, and pancreas.
7. Aortic Arch: This curved artery o Jejunal veins: Drain the
is the largest artery in the body. It jejunum (middle part of the
carries oxygenated blood from small intestine).
the left ventricle of the heart to o Ileal veins: Drain the ileum
the rest of the body.
(final part of the small in-
8. Left Subclavian Artery: This ar- testine).
tery is a branch of the aortic arch. o Superior pancreaticoduo-
It supplies blood to the left arm denal veins: Drain the
and shoulder.
pancreas and part of the
9. Left Brachial Artery: This artery duodenum (first part of the
is a continuation of the left sub- small intestine).
clavian artery.

10. Left Ulnar and Radial Ar- • Inferior Mesenteric Vein (IMV):
teries: These arteries supply Collects blood from the remain-
blood to the left hand and fore- ing part of the large intestine.
arm. o Left colic vein: Drains the
left part of the colon.
11. Left Deep Palmar Arch:
This arch is a network of arteries o Sigmoid vein: Drains the
located in the palm of the left sigmoid colon.
hand.
 o Superior rectal vein: • Oxygenated blood returns from
Drains the upper part of the the lungs to the heart via the pul-
rectum. monary veins.
9. Left Atrium:
2. Hepatic Portal Vein: • The pulmonary veins empty into
• The SMV and IMV merge to form the left atrium.
the hepatic portal vein. 10. Left Ventricle:
• This vein carries nutrient-rich • The left ventricle pumps oxygen-
blood from the intestines to the ated blood out of the heart into
liver. the aorta.
• The hepatic portal vein also re-
ceives blood from the spleen and 11. Aorta:
pancreas. • The aorta branches into numer-
3. Liver: ous arteries that supply blood to
• The liver filters the blood, remov- the entire body.
ing toxins, excess nutrients, and 12. Renal Arteries:
old red blood cells. • The aorta branches off into the
• The cleaned blood is then re- renal arteries, which carry blood
turned to general circulation via to the kidneys.
13. Kidneys:
the hepatic vein.
4. Inferior Vena Cava (IVC): • The kidneys filter waste products
• The hepatic vein drains into the and excess water from the blood,
IVC. forming urine.
• The IVC carries blood from the • The filtered blood is returned to
lower body back to the heart. general circulation via the renal
5. Right Atrium: veins.
• The IVC empties into the right 14. Inferior Vena Cava (IVC):
atrium of the heart. • The renal veins drain into the
6. Right Ventricle: IVC, completing the cycle.
• Blood is pumped from the right 65. Discuss how erythroblastosis fe-
atrium into the right ventricle. talis occurs.
7. Pulmonary Arteries:
• The right ventricle pumps blood Erythroblastosis fetalis is a severe
through the pulmonary arteries to condition that occurs when a pregnant
woman's immune system attacks the
the lungs for oxygenation.
red blood cells of her fetus. It's most
8. Pulmonary Veins:
commonly caused by a mismatch in
blood types between the mother and fe- detection and management of
tus. erythroblastosis fetalis.

How it occurs: 66. How does inflammation happen?

• Rh Incompatibility: The most Inflammation is a natural response by

common cause is when a woman the body's immune system to injury, in-
who is Rh-negative (lacks the Rh fection, or irritation. It's a protective
mechanism designed to help the body
protein on her red blood cells) be-
heal and fight off harmful invaders.
comes pregnant with an Rh-posi-
tive fetus (has the Rh protein). 1. Injury or Infection: When the
• Initial Exposure: During preg- body detects damage or a foreign
nancy or delivery, some of the fe- substance like bacteria, it triggers
tus's Rh-positive blood can cross an inflammatory response.
2. Blood Vessel Changes: Blood
the placenta and enter the moth-
vessels near the affected area di-
er's bloodstream. late (widen) to increase blood
• Immune Response: The moth- flow. This brings more oxygen
er's immune system, recognizing and nutrients to the site, as well
the Rh protein as foreign, pro- as immune cells to help fight off
duces antibodies against it. any infection.
• Subsequent Pregnancies: If the 3. Fluid and Cells: Fluid and white
blood cells (immune cells) leak
mother becomes pregnant with
out of the blood vessels into the
another Rh-positive fetus, her an- damaged tissue. This helps to
tibodies can cross the placenta flush out any harmful substances
and attack the fetus's red blood and promote healing.
cells. 4. Pain and Swelling: The in-
• Hemolysis: This destruction of creased fluid and pressure in the
red blood cells leads to anemia in area can cause swelling, pain,
and redness.
the fetus, which can cause seri- 5. Healing: Over time, the immune
ous health problems or even cells work to repair the damaged
death. tissue, and the inflammation sub-
sides.
Prevention:
Types of Inflammation:
• RhoGAM: Rh-negative women
can receive RhoGAM injections • Acute inflammation: This is a
short-term response that lasts for
during pregnancy and after deliv-
a few days or weeks.
ery to prevent the development of • Chronic inflammation: This is a
antibodies against the Rh protein. long-term response that can last
• Prenatal Care: Regular prenatal for months or even years.
check-ups are essential for early
Common Causes of Inflammation:
 • Injuries (cuts, bruises, burns) Meiosis, on the other hand, results in
• Infections (bacterial, viral, fungal) four daughter cells because it's specif-
• Allergies ically designed to produce gametes
• Autoimmune diseases
(sperm or egg cells) for sexual repro-
• Certain medical conditions (arthri-
tis, asthma) duction. These gametes need to have
half the number of chromosomes as the
67. Describe the negative and posi- original cell so that when they combine
tive feedback mechanism. during fertilization, they create an em-
bryo with the correct number of chromo-
Negative feedback: somes.
• Goal: To maintain a stable state. Here's a simplified analogy:
• How it works: When a variable
deviate from its ideal state, a re- • Mitosis is like photocopying a
sponse is triggered to bring it book. You get one exact copy.
back. Think of it like a thermostat: • Meiosis is like cutting a book in
When it gets too hot, it turns on half and then photocopying each
the AC to cool it down. half. You get two halves, and
• Example: Regulating body tem- each half is a unique part of the
perature. original book.

Positive feedback: The reason for the different outcomes is

rooted in the biological functions of
• Goal: To amplify a change. these processes. Mitosis is for growth
• How it works: When a change and repair, while meiosis is for creating
occurs, a response is triggered to new life.
make that change even bigger.
Think of it like a snowball rolling 69. What are the different membrane
downhill: It gets bigger and faster transport mechanisms?
as it goes.
• Example: Childbirth. The con- Membrane transport is the movement
tractions get stronger and of substances across a cell membrane.
stronger until the baby is deliv- It can be either passive or active.
ered.
Passive Membrane Transport occurs
68. Compare mitosis and meiosis. without the expenditure of cellular en-
ergy. It relies on the inherent kinetic en-
Mitosis results in two daughter cells ergy of molecules.
because it's a process of cell division
that aims to create an exact copy of the • Diffusion: Molecules move from
original cell. The goal is to replace high to low concentration.
worn-out cells or to help the organ- • Osmosis: Water moves from low
to high solute concentration.
ism grow.
 • Facilitated diffusion: Proteins
help molecules move across the Oncotic Pressure
membrane.
• Definition: A specific type of os-
Active Membrane Transport requires motic pressure exerted by pro-
the expenditure of cellular energy, usu- teins, primarily albumin, in a solu-
ally in the form of ATP. tion.
• How it works: Similar to osmotic
• Active transport: Directly uses pressure, but specifically focused
ATP to pump molecules. on proteins. Albumin, being a
• Secondary active transport: large protein, attracts water mol-
Uses energy indirectly, often cou- ecules, contributing to the overall
pled with another molecule's osmotic pressure of blood
movement. plasma.
• Endocytosis: Cell takes in sub-
stances by forming a vesicle. • Example: Low albumin levels in
• Exocytosis: Cell releases sub- the blood, a condition called hypo-
stances by fusing a vesicle with albuminemia, can lead to edema
the membrane. (swelling) due to reduced oncotic
70. Compare osmotic pressure, on- pressure, causing fluid to leak into
cotic pressure, filtration pressure surrounding tissues.
and hydrostatic pressure. Filtration Pressure
These four terms are related to fluid • Definition: The net pressure
movement across semi-permeable driving fluid movement across a
membranes, particularly in the context membrane, typically a capillary
of blood vessels. wall.
• How it works: It's the difference
between hydrostatic pressure
Osmotic Pressure and oncotic pressure.
• Definition: The pressure exerted • Example: In the capillaries, filtra-
by a solution due to its solute tion pressure drives fluid out of
concentration. the capillaries into the surround-
• How it works: Solutes, like pro- ing tissues (filtration).
teins or salts, attract water mole-
cules. The higher the solute con- Hydrostatic Pressure
centration, the more water it
draws, creating a pressure.
• Example: Saltwater has a higher • Definition: The pressure exerted
by a fluid against a container
osmotic pressure than freshwater wall.
due to its higher salt concentra- • How it works: It's essentially the
tion, causing water to move from force of the fluid pushing out-
freshwater to saltwater. ward.
 • Example: Blood pressure is a • Location: Attached to bones by
type of hydrostatic pressure ex- tendons.
erted by blood against the walls of • Control: Consciously controlled
blood vessels. by the nervous system.
• Example: Biceps, quadriceps,
In summary: pectorals.
• Osmotic and oncotic pressures are
Cardiac Muscle
related to the concentration of solutes
and proteins, respectively, and tend to • Structure: Striated appearance
draw water into a solution. similar to skeletal muscle, but
• Filtration pressure is the net result of cells are branched and intercon-
hydrostatic and oncotic pressures and nected.
determines the direction of fluid move- • Function: Pumping blood
ment. throughout the body.
• Hydrostatic pressure is a physical • Location: Walls of the heart.
force that pushes fluid out of a vessel. • Control: Involuntary, contracts
A common example is the exchange rhythmically on its own.
of fluids in capillaries. Hydrostatic pres- • Example: Myocardium.
sure pushes fluid out of the capillary,
while oncotic pressure draws it back in. Smooth Muscle
The net filtration pressure determines
whether fluid moves out of or into the • Structure: Non-striated (smooth)
capillary. appearance.
• Function: Involuntary movement
71. Compare and contrast the differ- of internal organs, such as diges-
ent types of muscles. tion, blood vessel constriction,
and pupil dilation.
The human body contains three main • Location: Walls of hollow organs,
types of muscle tissue: skeletal, car- such as the intestines, blood ves-
diac, and smooth. Each type has dis- sels, and uterus.
tinct characteristics, functions, and lo- • Control: Involuntary, controlled
cations. by the autonomic nervous sys-
tem.
Skeletal Muscle
• Example: Muscles in the diges-
• Structure: Striated (striped) ap- tive tract, blood vessels.
pearance due to the arrangement
Comparison Table:
of protein filaments.
• Function: Voluntary movement, Fea- Skeletal Car- Smooth
maintaining posture, generating ture Muscle diac Muscle
heat. Muscle
Struc- Striated Stri- Non-stri- 1. Connective Tissue Proper
ture ated ated o Loose connective tissue:
Func- Volun- Pump- Involun- ▪ Contains a loose ar-
tion tary ing tary rangement of fibers
move- blood move- and cells.
ment, ment of ▪ Examples: areolar tis-
posture organs sue, adipose tissue,
Loca- At- Heart Walls of reticular tissue.
tion tached walls hollow or- o Dense connective tissue:
to gans ▪ Contains a dense ar-
bones rangement of fibers
Con- Volun- Invol- Involun- and cells.
trol tary untary tary ▪ Subtypes:
Exam- Biceps, Myo- Muscles ▪ Regular: Fibers
ple quadri- car- in intes- are arranged in
ceps dium tines, parallel bun-
blood dles.
vessels ▪ Example:
tendons,
In summary, while all three muscle ligaments.
types share the ability to contract and ▪ Irregular: Fi-
generate force, they have distinct struc- bers are ar-
tures, functions, and locations in the hu- ranged in a ran-
man body. Skeletal muscles are re- dom pattern.
sponsible for voluntary movement, car- ▪ Example:
diac muscle pumps blood, and smooth dermis of
muscle controls involuntary movements the skin.
of internal organs. 2. Specialized Connective Tissue
o Cartilage:
72. Compare and contrast the differ-
▪ Firm but flexible ma-
ent connective tissues.
trix containing chon-
Connective tissues are a diverse drocytes.
▪ Subtypes: hyaline
group of tissues that share the common
function of connecting, supporting, and cartilage, elastic carti-
protecting other tissues in the body. lage, fibrocartilage.
o Bone:
They are composed of cells, fibers, and
▪ Hard, calcified matrix
a ground substance, which vary in com-
position and arrangement depending on containing osteo-
the specific type of connective tissue. cytes.
o Blood:

Major Types of Connective Tissue

 ▪ Fluid matrix (plasma) • Simple Squamous Epithelium:
containing various cell Flattened cells, found in the alve-
types. oli of the lungs, blood vessels,
and the lining of the heart.
o Adipose tissue:
• Simple Cuboidal Epithelium:
▪ Specialized for stor-
Cube-shaped cells, found in the
age of fat. kidney tubules, ducts of glands,
o Reticular tissue: and the ovary.
▪ Network of reticular fi- • Simple Columnar Epithelium:
bers supporting or- Column-shaped cells, found in
gans. the lining of the digestive tract,
the uterus, and the fallopian
Key Differences tubes.

Stratified Epithelium: Consists of

• Cell types: Different connective
multiple layers of cells.
tissues have specialized cell
types that perform specific func- • Stratified Squamous Epithe-
tions. lium: Can be keratinized (found
• Fiber arrangement: The ar- in the epidermis of the skin) or
rangement of fibers varies de- non-keratinized (found in the lin-
ing of the mouth, esophagus, and
pending on the tissue's function.
vagina).
• Ground substance composi- • Stratified Cuboidal Epithelium:
tion: The ground substance can Rare, found in the ducts of sweat
be liquid, gel-like, or solid, affect- glands and mammary glands.
ing the tissue's properties. • Stratified Columnar Epithe-
• Function: Connective tissues lium: Also rare, found in the lin-
ing of the urethra and the ducts
perform a wide range of functions,
of some glands.
including support, protection, in-
sulation, and transport. Pseudostratified Epithelium: Ap-
pears stratified but is actually a single
73. Compare and contrast the differ- layer of cells with different heights.
ent epithelial tissues. Found in the lining of the respiratory
tract.
Epithelial tissues are sheets of cells
that cover the body's surfaces, both in- Transitional Epithelium: A special-
ized type of stratified epithelium that
ternal and external. They play a crucial
can stretch and change shape. Found
role in various functions, including pro- in the urinary bladder, ureters, and part
tection, absorption, secretion, and sen- of the urethra.
sation.
74. Describe how transcription and
Simple Epithelium: Consists of a translation happens.
single layer of cells.
Transcription: DNA to RNA
 Transcription is the process of copying
DNA into RNA (mRNA). RNA polymer- Non-membrane-bound organelles:
ase binds to a DNA sequence called a • Ribosomes: Sites of protein synthesis.
promoter, unzips the DNA, and adds • Cytoskeleton: A network of protein fil-
complementary RNA nucleotides. aments that provides structural support
When it reaches a terminator, the and aids in cell movement.
mRNA is released. • Centrosome: Contains centrioles,
which play a role in cell division.
Translation: RNA to Protein • Cilia and flagella: Hair-like structures
that aid in cell movement.
Translation is the process of convert-
• Nucleolus: A region within the nucleus
ing mRNA into a protein. Ribosomes
where ribosomes are assembled.
bind to the mRNA at the start codon
(AUG) and read it in codons (3-nucleo-
tide sequences). tRNA molecules carry-
ing the corresponding amino acids bind
to the codons, and the amino acids are
linked together by peptide bonds to
form a protein. The process ends when
a stop codon is reached.

75. What are the different organelles

found in the cytoplasm?

Membrane-bound organelles:
• Endoplasmic reticulum (ER):
o Rough ER: Studded with ribosomes, it
synthesizes proteins.
o Smooth ER: Synthesizes lipids, detox-
ifies substances, and stores calcium
ions.
• Golgi apparatus: Modifies, packages,
and sorts proteins and lipids.
• Mitochondria: The "powerhouse of
the cell," they produce energy through
cellular respiration.
• Lysosomes: Contain enzymes to
break down cellular waste and debris.
• Peroxisomes: Break down fatty acids
and toxic substances.
• Vacuoles: Store water, waste prod-
ucts, and other substances.