CHAPTER: LIFE PROCESSES TOPIC: TRANSPORTATION
➢ Transportation in animals refers to the process by which essential substances like oxygen,
nutrients, hormones, and waste products are carried to and from different parts of the
body through a specialized transport system, usually the circulatory system.
➢ Components of transport system:
Blood :
• Fluid connective tissue (can flow, connects different body organs and made up of
different types of cells -RBC, WBC and Platelets
• Red coloured liquid (due to red pigment- haemoglobin)
• 5 to 6L in an adult.
• Consists of (A) Plasma : 55% of blood
The liquid part, colourless
Composition: Water 90–92% of plasma (acts as a solvent and carrier)
Proteins 7-8%
Albumin – maintains osmotic pressure
Globulin- Involved in immunity
Fibrinogen – Helps in blood clotting
Nutrients- glucose, Amino acids, lipids and vitamins
Hormones- transported from endocrine glands to
target glands
Inorganic salts(electrolytes) – Na-, K+, Ca2+. Mg2+, Cl-,
HCO3-
Waste products – urea, uric acid and creatinine
Respiratory gases- CO2 and O2 (small amounts)
Plasma is mainly composed of water, plasma proteins, electrolytes, nutrients, hormones, and
wastes, making it essential for transportation and homeostasis in the body.
(B) Formed elements (blood corpuscles): 45% of blood
The solid part of the blood
Suspended in plasma
Feature RBC WBC Platelets
Scientific name erythrocyte leucocyte thrombocyte
Number (per mm³) ~5 million ~6,000–8,000 ~2,50,000–4,00,000
Size ~7.2 µm ~12–20 µm (varies by type) ~2–3 µm
Structure Biconcave, disc-shaped Round/irregular; may have lobed disc-like fragments (non-cellular)
nucleus
Colour Red (due to haemoglobin) Colourless Colourless
Nucleus Absent Present (single or multilobed) Absent
Function Transport of oxygen and Defense against infections and immune Help in blood clotting
carbon dioxide response.( phagocytosis, inflammation
and antibiotic production)
Life Span ~120 days Few hours to few days (varies by type) 7–10 days
Formation Site Red bone marrow Bone marrow and lymphatic tissues Red bone marrow
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Granulocytes:
Diagram
Agranulocytes
1. B – Lymphocytes
(produce antibodies)
2. T -lymphocytes
(help B -lymphocytes
to produce antibodies)
Q. Why mature mammalian RBC lacks nucleus, mitochondria and ER?
Ans: Nucleus: Lost during maturation to make more space for hemoglobin, which increases oxygen-
carrying capacity.
Mitochondria: Absent so that RBCs do not use up the oxygen they carry; instead, they rely on
anaerobic glycolysis for ATP production
Endoplasmic Reticulum: Absent because RBCs do not synthesize proteins once mature.
Significance of This Adaptation
More space for hemoglobin.
Biconcave shape for increased surface area and flexibility to pass through narrow capillaries.
Longer lifespan (~120 days in humans) without risk of nuclear or mitochondrial damage.
Q. What is the affinity of Hb to oxygen, carbon dioxide and carbon monoxide?
Ans: Order of Affinity (Highest → Lowest): CO > O2 > CO2
Carbon Monoxide (CO)
• Affinity: ~ 200–250 times greater than oxygen.
• Binds to the heme (iron) site forming carboxyhemoglobin (HbCO).
• Binding is irreversible (or very slow to reverse) → blocks O₂ transport → causes CO
poisoning.
Oxygen (O₂)
• Affinity: High (but much less than CO).
• Binds to heme site forming oxyhemoglobin (HbO₂).
• Binding is reversible → allows oxygen to be picked up in lungs and released in
tissues.
Carbon Dioxide (CO₂)
• Affinity: Lower compared to O₂ and CO.
• Binds to amino groups of the globin part (not heme) → forms carbaminohemoglobin
(HbCO₂).
• Binding is reversible and easily broken in lungs for CO₂ release.
Q, Explain the process of blood clotting.
Blood vessel injury
↓
Vasoconstriction
(blood vessels narrow to reduce blood loss)
↓
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Platelet activation & aggregation
(platelets stick to injury site → form temporary plug)
↓
Release of clotting factors
(from platelets and damaged tissues)
↓
Activation of Prothrombin into Thrombin
(with help of calcium ions and clotting factors)
↓
Conversion of Fibrinogen into Fibrin
(by thrombin enzyme)
↓
Fibrin mesh formation
(traps blood cells → forms stable clot)
↓
Clot retraction & repair
(wound healing begins)
Blood vessels: Blood vessels are tubular structures in the circulatory system that carry blood
throughout the body, transporting oxygen, nutrients, hormones, and waste products to and from
the heart and various tissues.
Three types: Arteries, Veins and Capillaries
Characteristic Arteries Veins Capillaries
Origin Heart → Body Body → Heart Exchange between
blood & tissues
Type of blood oxygenated blood (except deoxygenated blood Transition between
pulmonary artery). (except pulmonary veins). oxygenated and
deoxygenated blood.
Presence of valves no valves. valves present to prevent no valves.
backflow
Blood pressure High low low
Location Deep inside, e.g., aorta, Both superficial (under In all organs & tissues,
carotid artery, femoral skin) & deep (e.g., vena e.g., lungs, kidneys,
artery cava, femoral vein) muscles
Wall type Thick, muscular, elastic Thinner walls one cell thick
walls
Lumen Narrow lLarge Very narrow
Diagram
Q. What is diapedesis?
Diapedesis (emigration) is the process by which WBCs squeeze through the walls of tiny blood
vessels to reach tissues where they are needed, usually at a site of infection or injury.
Fig B and Fig C shows phagocytosis process by which WBC destroy microbes that enter our
body.
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Heart:
Location: In the thoracic cavity, between the lungs, slightly tilted to the left.
Size: About the size of a closed fist (~12 cm length, ~250–300 g in weight).
Type of muscle: Made of cardiac muscle (involuntary, striated).
Function: Pumps blood throughout the body via the circulatory system.
Chambers : 4 chambered
1. Right Atrium
✓ Thin-walled chamber.
✓ Receives deoxygenated blood from the body via:
Superior vena cava (upper body)
Inferior vena cava (lower body)
Coronary sinus (from heart muscles)
2. Right Ventricle
✓ Thick-walled chamber.
✓ Pumps deoxygenated blood to the lungs through the pulmonary artery.
3. Left Atrium
✓ Receives oxygenated blood from lungs via four pulmonary veins.
4. Left Ventricle
✓ Thickest wall of all chambers (highest pumping force).
✓ Pumps oxygenated blood to the body via the aorta.
Valves: Prevent backflow of blood:
✓ Tricuspid valve → Between right atrium & right ventricle.
✓ Bicuspid (Mitral) valve → Between left atrium & left ventricle.
✓ Pulmonary semilunar valve → At opening of pulmonary artery.
✓ Aortic semilunar valve → At opening of aorta
Associated Blood Vessels
✓ Aorta → Carries oxygenated blood to body.
✓ Pulmonary artery → Carries deoxygenated blood to lungs.
✓ Pulmonary veins → Carry oxygenated blood to heart.
✓ Vena cavae → Bring deoxygenated blood from body to heart.
Septa
✓ Interatrial septum → Between right & left atria.
✓ Interventricular septum → Between right & left ventricles.
Conducting System
✓ SA Node (Sinoatrial Node) → Natural pacemaker; initiates heartbeat.
✓ AV Node (Atrioventricular Node) → Pace setter; Relays signal to ventricles.
✓ Bundle of His & Purkinje fibers → Spread signal for ventricular contraction.
Pericardium
✓ A double-layered membrane that encloses the heart, with pericardial fluid to reduce
friction during beating.
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Phases of heart: Two main phases
1. Ventricular filling 2. Ventricular emptying
(Atrial systole and ventricular diastole) (Ventricular systole and atrial diastole)
Q. Define coronary artery. What happens if it gets blocked?
Ans: The artery that carries that oxygenated blood to heart muscles.
Effects of Coronary Artery Blockage
1. Reduced oxygen supply → Heart muscle cells can’t function properly.
2. Chest pain (angina pectoris) → Especially during exertion, due to inadequate oxygen.
3. Myocardial infarction (heart attack) → If the blockage is severe and prolonged, heart
muscle tissue may die.
4. Arrhythmias → Abnormal heart rhythms due to damaged conduction pathways.
5. Heart failure → If a large part of the muscle is affected, the heart’s pumping ability is
reduced.
Q. What are blue babies?
Blue babies (Cyanosis ) is a term used for new borns or infants who appear bluish (cyanotic) due to a
lack of oxygen in the blood.
Causes: 1. reduced oxygen saturation in haemoglobin
2. congenital heart defects that allow mixing of oxygenated and deoxygenated blood.
Q. What is blood pressure(BP)?
Blood pressure is the force exerted by circulating blood on the walls of blood vessels, especially
arteries.
For a healthy adult:
120/80 mmHg(systolic/diastolic)
Q. What is pulse pressure (PP)?
Ans: Pulse Pressure is the difference between systolic blood pressure (SBP) and diastolic blood
pressure (DBP).
Example
If BP = 120/80 mmHg:
Pulse Pressure=120−80=40 mmHg\text{Pulse Pressure} = 120 - 80 = 40 \;
\text{mmHg}Pulse Pressure=120−80=40mmHg
Normal Value
• Normal range: 30–50 mmHg
• Around 40 mmHg is considered healthy in adults.
Significance
• High Pulse Pressure → Can indicate stiff arteries (e.g., in arteriosclerosis, hypertension).
• Low Pulse Pressure → Can occur in blood loss, shock, or heart failure.
Q. Why high salt intake is not advisable to BP patients?
Ans: High salt intake is not advisable for a blood pressure (BP) patient because excess sodium in salt
can make the body retain more water, which increases the volume of blood in circulation.
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Mechanism of heart
• When the muscles of all the 4 chambered are relaxed , the pulmonary vein brings the
oxygenated blood from lungs to the left auricle.
• When the LA contracts , the oxygenated blood is pushed into the left ventricle through
bicuspid valve (Mitral valve).
• When the LV contracts , the oxygenated blood is forced into the main artery called aorta .
The main artery then branches into smaller arteries called arterioles taking the blood to
different organs.
• The CO2 produced as a waste material during respiration enters into the blood . The
deoxygenated blood from organs enters the main vein called vena cava which carries the
deoxygenated blood to the RA.
• When the RA contracts, deoxygenated blood is pushed into the RV through the tricuspid
valve.
• When the RV contracts , the deoxygenated blood is pumped into the lungs through
pulmonary artery.
• In the lungs , deoxygenated blood receives oxygen from air. So the blood becomes
oxygenated again.
• This oxygenated blood is again sent to the LA of the heart by pulmonary vein for circulation
in the body.
Human circulatory system is dual and closed type as blood flows within blood vessels and blood
passes the heart twice in one course of circulation.
Schematic representation of transport and exchange of oxygen and carbon dioxide.
Double circulation in man- The circulatory system of man is called double circulation as the blood
passes through the heart twice in one complete cycle of human body.
This includes two circulations:
Pulmonary circulation:
Maintained by the right side of the heart.
Begins in the right ventricle which expels the blood into the pulmonary artery.
The blood becomes oxygenated in lungs and is returned to the heart (LA) through pulmonary veins.
Systemic circulation:
Maintained by the left ventricle which send the blood into the aorta.
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The aorta divides into arteries , arterioles and finally to capillaries supplying oxygenated blood to
organs. From there the deoxygenated blood is collected by venules joining to form veins and finally
pour into vena cava bringing the blood back into the heart.
LUNGS
Pulmonary artery Pulmonary vein
Pulmonary
circulation
Right Atrium
Right Ventricle Left
Ventricle
Vena cava Aorta
Capillaries
Fig 6.15. Schematic representation of double circulation in human.
Lymph
It is a colorless body fluid present in many higher animals.
It flows in the lymphatic system (an open circulatory system).
Lymph is formed in the tissue space (interstitial space).
Components
1. Lymphatic plasma: 2. Cells
Water Leucocytes-Lymphocytes
Nutrients- small quantities of glucose, amino acids, vitamins and minerals. No RBCs and platelets.
Large quantity of fatty acids and glycerol. No respiratory pigments
Plasma proteins- small quantities of albumins, globulins and fibrinogen.
Respiratory gases- small quantities of oxygen and carbon dioxide compared to blood.
Some metabolic wastes, large number of cellular debris and bacteria.
Steroid hormones
Formation of lymph
• When blood capillaries come in contact with the tissues for exchange of substances between
blood and the cells.
• Considerable amount of plasma gets released out from through the thin capillary walls.
• This plasma gets filled in the space between cells of the tissues.
• It is forms the Extra Cellular Fluid (ECF) in the tissue space.
• It is called tissue fluid or interstitial fluid.
• The lymphatic capillaries (originating from the tissue) collect a significant amount of the
tissue fluid and form lymph.
• Lymph collects various lymphocytes from various lymphatic organs.
• It collects fatty acids and glycerol from the small intestine through lacteals.
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Movement of lymph
• Lymphatic system has no pumping organ.
• Pressure of the fluid is comparatively lower.
• Valves are present in the lymphatic vessels to prevent back-flow.
• The lymphatic vessels are present mostly in close proximity to the large arteries.
• Their contraction makes lymph to move against gravity.
• Contraction of skeletal muscles and thoracic pressure gradients created by the
• breathing movements contribute to the unidirectional flow of lymph.
Lymph is known as “middle man” as High salt intake is not advisable for a blood pressure (BP)
patient delivering nutrients & oxygen from blood to cells and collecting
wastes & CO₂ from cells.
