General Physiology

By
Dr/ Hanaa Mostapha Badran
Our Agenda
Theoretical practical
topic 1 General physiology Cell membrane
topic 2 Blood components Transport across cell membrane
topic 3 Haemostasis comple blood counts
topic 4 Blood group blood group and erythrocyte
sedimentation rate

topic 5 Nervous system resting membrane potential

topic 6 Action potential
topic 7
topic 8 Muscle contaction simple muscle twith
topic 9 function of autonomic nervous autonomic ganglia
system

topic10 Autonomic chemical transmitters Vital signs

and receptors

topic11 regulation of respiration respiratory function tests

topic12 Hypoxia and cyanosis
What is physiology?

Physiology is the study of how living

organism’s body work functions of the
normal living organs and how these
functions interplay to maintain human
existence and well being.
Physiology is the basis of medicine
 Functions of body water

• 1. It is the origin of life.

• 2. Media for all biological reactions.

• 3. Ionization of dissolved salts.

• 4. It regulates body temperature.

• 5. It gives the blood its fluidity.

 Total body water
Total body water TBW = 60% x Body Weight in kilograms
Intracellular Fluid (ICF): The amount of water that’s inside our cells accounts for 2/3rds of our
TBW.
Extracellular Fluid (ECF): The amount of water that surrounds our cells accounts for 1/3 of our
TBW. ECF is also known as interstitial fluid because it’s the fluid in between the cells.

Tissue fluid: 2/3rd of ECF

Blood plasma: 1/3rd of ECF
Total Blood Volume (TBV)
Blood is made up of blood cells and blood plasma.
TBV = 8% x Body Weight (kg).
Distribution of total body water
The body fluids are solutions of water, dissolved in this water many organic
molecules (carbon-containing molecules such as carbohydrates, lipids, proteins,
and nucleic acids), as well as inorganic molecules and ions
Body fluids
• There are very important differences between the electrolytes inside and outside
the cell

ICF ECF
• K+ Na+
• Mg+2 Ca+2
• PO4 -3 Cl-
• Protein – HCO3-

(due to negatively charged amino acids in proteins)

there’s a high amount of potassium (K+) inside the cell.
there’s a high amount of sodium (Na+) outside the cells.
Body fluids
Extravascular body fluids
• Pleural fluid.
• Pericardial fluid.
• Peritoneal fluid (ascites).
• Amniotic fluid.
• Cerebrospinal fluid.
• Semen.
• Urine.
• Sputum.
• Saliva.
• Nasal secretion.
• Sweat.
• Stool.
• Vaginal secretions.
• Synovial fluid.
• Tears.
Body fluids
Cell
 Definition of cell membrane
-It is a thin elastic semi-permeable membrane that surrounds
the cell.

-Semi-permeable means allowing some substances to pass

through it and prevent others).

-Its thickness is about 7.5 nm.

(75 Ao = Angstrom = 10-10 of meter).

 Functions of cell membrane
• It separates the cytoplasm from ECF
• It maintains cell's internal environment
• It controls distribution of ions e.g Na+, K+ into and out of
the cell.
• 4-It contains receptors for hormones and transmitter
substances
• It generates membrane potentials.
Integral proteins:
Span the membrane.
Proteins provide structural
channels or pores.
Carrier proteins.

2- Peripheral protein: Present

in one side. Hormone receptors.
Cell membrane antigens
Phospholipids (Amphipathic) : P
• It is formed of 3 components:

•-
Membrane phospholipids

Hydrophilic heads
PO4-

Hydrophobic tails
F.A
 ECF Bilayer

Hydrophobic area

ICF Cholesterol
Transport through cell membrane

O2 and nutrients

Cell

CO2 and wastes

 Transport through cell membrane

Passive:down its electro-

Diffusion
chemical gradient.

2- doesn’t need energy.

against electro-chemical
Active
gradient.
transport
2- needs energy

large sized substance

Vesicular
transport
Resting membrane potential
• The negative values indicate that the cytosol (intracellular fluid)
is more electronegative than the extracellular fluid. The values
of EM depend on several factors:
• Concentration of ions inside and outside the cell. Ions that
contribute the most are the sodium, potassium, calcium, and
chloride ions.
• Activity of the sodium-potassium pump.
• Variable permeability of the cell membrane for ions.
 Causes of RMP

• unequal distribution of ions across the cell

membrane
Selective permeability of the cell membrane

Na+ - K+ pump

The membrane is impermeable to the

intracellular protein anions
Resting membrane potential
• Resting membrane potential (EM) originates from the different
concentrations of ions (expressed in mmol/l) at the inner and
outer surface of the cell membrane. There are four excitable
tissues in our body, and all of them have different EM values:
• Skeletal muscle cell= -90 millivolts (mV)
• Smooth muscle cell = -55mV
• Cardiac muscle cell = -80mV
• Neuron= -65mV
 Homeostasis
Homeostasis is the state of steady internal chemical and
physical conditions maintained by living systems.”
Homeostasis
• is a mechanism that maintains a stable internal environment internal milieu despite the
changes present in the external environment.
• It is the job of cells, tissues, organs, and organ systems throughout the body to maintain
many different variables within narrow ranges that are compatible with life. Keeping a
stable internal environment requires continuous monitoring of the internal environment
and constantly making adjustments to keep things in balance
• .The body maintains homeostasis by controlling a host of variables ranging from body
temperature, blood pH, blood glucose levels to fluid balance, sodium, potassium and
calcium ion concentrations.
Component:
• Receptor
• Control center
• effector
homeostasis
Many factors can affect homeostasis. The most common are:
• Genetics.
• Physical condition.
• Diet and nutrition.
• Venoms and toxins.
• Psychological health.
• Side effects of medicines and medical procedures.
homeostasis.
• Blood glucose homeostasis.
• Blood oxygen content homeostasis.
• Extracellular fluid pH homeostasis.
• Plasma ionized calcium homeostasis.
• Arterial blood pressure homeostasis.
• Core body temperature homeostasis.
• The volume of body water homeostasis.
• Extracellular sodium concentration homeostasis.
• Extracellular potassium concentration homeostasis.
• Blood partial pressure of oxygen and carbon dioxide homeostasis.
 Feedback mechanisms

• It is a physiological regulatory system that returns the body to a normal

internal state (homeostasis)

Types of feedback

• Negative feedback

• Positive feedback
feedback loops into two main types:
• 1. positive feedback loops, in which a change in a given
direction causes additional change in the same direction.
• 2. negative feedback loops, in which a change in a given
direction causes change in the opposite direction.
Types of feedback
• positive feedback loops, in which a change in a given direction
causes additional change in the same direction.
Eg: Normally Prolactin stimulates milk production
during pregnancy, progesterone inhibits Prolactin No milk production.
At birth Prolactin surges resulting in milk production
. As the baby feeds, its suckling stimulates the breast, promoting further release of prolactin,
resulting in yet more milk production

• negative feedback loops, in which a change in a given direction

causes change in the opposite direction.For example, For example,
pupillary diameter is adjusted to make sure an appropriate amount of light
is entering the eye. If the amount of light is too low, the pupil dilates, if it is
too high, the pupil constricts.
Homeostasis and feedbacks
Negative feedback
Wrap up

organs Organ tissues cells

systems tissues
 Wrap
up
• Cells contains ICF & surrounded by ECF.

• Total body water 42 L: 28 L (ICF), 14 L (ECF).

• Homeostasis

• Types of feedback.

• Constituents of cell membrane: lipid, protein, carbohydrates

 Wrap up

cause of RMP:
● Unequal distribution of ions across cell membrane due to:

1. Membrane selective permeability

2. Na+ -K+ pump

3. impermeability of intracellular protein

 MCQ
• 1. Total body water for 70 kg adult male is?

A. 50 L
B. 52 L
C. 62 L
D. 42 L
 MCQ
• 2. intracellular fluid differs from extracellular fluid in:

A. It has higher Na level.

B. It has higher Cl level
C. It has higher K level
D. It has higher Ca level.
 MCQ

3. When body temperature increase, blood vessels dilate to enhance

temperature loss, this is considered:

A. Negative feed back

B. Positive feed back

C. Both A & B

D. Neither A or B
 MCQ

4. When hormone A increase, it stimulates hormone B release, then

hormone B stimulates further release of hormone A. This is considered:

A. Negative feed back

B. Positive feed back

C. Positive followed by negative feed back

D. Negative followed by positive feed back

• 5. Constituents of cell membrane:
A.Lipid
B. protein
C. carbohydrates
D.All of the above