1. Transport in Human

2. At the end of the lesson, you should be able to
 State the functions of blood:
 Red blood cells – haemoglobin which aids in oxygen
transport
 White blood cells – phagocytosis, antibody
formation and tissue rejection
 Platelets – fibrinogen to fibrin, causing clotting
 Plasma – transport of blood cells, ions, soluble food
substances, hormones, carbon dioxide, urea,
vitamins, plasma proteins
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3. What is Blood? Blood
3 types of cells present in the
human blood cell:
• red blood cells
(erythrocytes)
• white blood cells
(leukocytes) plasma, 55%
• platelets (thrombocytes)
Plasma is a liquid consisting
91% water which has
blood cells, 45%
inorganic ions, nutrients,
waste products, hormones
and soluble proteins dissolved
in it.
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4. Red Blood Cells Blood
 Formed in bone marrows of long bones.
 Formed from nucleated cells called erythroblasts.
 Exposed to maximum surface area for the exchange of
oxygen and carbon dioxide.
 95% of the protein in red blood cell is haemoglobin and
5% of the protein are enzymes that allow the cell to
survive for about 120 days.
cytoplasm
containing
haemoglobin
plasma
membrane
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5. Red Blood Cells Blood
 The binding of oxygen to haemoglobin is reversible.
 In the lungs, where oxygen concentration is high, oxygen
combines with haemoglobin to form oxyhaemoglobin.
 When blood arrives at cells where the oxygen concentration
is low, it unloads and becomes maroon haemoglobin once
again.
high oxygen concentration
Hb + 4O2 Hb(O2)4
(haemoglobin) low oxygen concentration (oxyhaemoglobin)
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6. Red Blood Cells Blood
 As red blood cells pass through tissues, they pick up carbon dioxide.
 Most of the carbon dioxide combines with water to form carbonic acid.
CO2 + H2O H2CO3
carbonic
acid
 The carbonic acid then ionises to form hydrogen ions and hydrogen
carbonate ions.
H2CO3 H+ + HCO¯
3
carbonic acid hydrogen hydrogen
ion carbonate ion
 About 70% of the ions leave the red blood cells and remain in plasma.
 When the blood reaches the lungs, carbon dioxide is released and
diffuses out of the blood to enter the alveoli.
 Carbon dioxide is then breathed out.
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7. What is anaemia?
 Lower red blood cell count
 Caused by deficiency in
iron in diet leading to less
haemoglobin being
produced
Symptoms:
 Easily tired, looks pale,
breathless
 Who’s vulnerable? Pregnant
ladies, people who have lost large
amounts of blood

8. Why do people
living in high
altitudes have rosy
cheeks?
 Concentration of oxygen in air is lower
 Absorb insufficient oxygen for respiration
 Acclimatisation  Body produces more red
blood cells  increase amount of haemoglobin
per unit volume of blood
 Hence more oxygen can be transported to cells

9. Blood group
 Red blood cells carry special protein called antigens
on their cell surfaces. Blood plasma contains
antibodies.
 Blood groups are classified according to the
antibodies and antigens present in their blood.
 There are four groups of blood, named A, B, AB and
O.
 Each group is named after the antigen present.
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