Question 1:
Figure below shows part of the circulatory system and the lymphatic system in the human body.


(a)(i) What is fluid V? [1 mark]

(ii) What happens to the components of fluid V when it passes through the lymph node? [1 mark]

(b)(i) Fluid V originates from the blood.
Describe how fluid V is formed from the blood. [2 marks]

(ii) State one difference between fluid V and the blood. [1 mark]


(c)(i) A part of vessel T is blocked.
Explain its effect on the system in the Figure. [2 marks]

(ii) Vessel T in the leg is blocked.
What would happen to the leg? [1 mark]

(d) The blood circulatory system and the lymphatic system function to maintain the composition of the tissue fluid.
Explain how the composition of the tissue fluid is maintained by stating the substances transported by the blood circulatory system and the lymphatic system. [3 marks]



Answer:
(a)(i)
Fluid V = Lymph

(a)(ii)
Toxic substances and pathogens are neutralized/ destroyed.

(b)(i)
Blood plasma diffuses from the capillaries. The tissue fluid formed diffuses into the lymphatic vessels.

(b)(ii)
Fluid V does not have erythrocytes whereas blood has erythrocytes. Fluid V is clear yellowish whereas blood is red in colour.


(c)(i)
Interstitial fluid fails to return to the blood circulatory system. Tissue fluid accumulates in the spaces between the cells.

(c)(ii)
The leg will be swollen.

(d)
Dissolved substances such as glucose and amino acids are transported in the blood circulatory system entering the body tissues forming tissue fluid. Fatty acids and glycerol are transported by the lymphatic system into the blood circulatory system. Some of the contents of the tissue fluid enter the lymphatic system and some enter the blood circulatory system at the ends of the venules.

Question 1:
(a)(i) Diagram below shows an electron micrograph of cellular components of human blood.


Based on Diagram I, explain how platelets help to stop bleeding when a wound occurs. [4 marks]

(ii) A blood test shows that a man’s erythrocytes count is below normal.
Explain the possible consequences of this condition on his health.
What type of food should be included in his diet to improve this condition? [8 marks]


(b) Diagram II shows the blood circulatory system in organism P and organism Q.


Based on Diagram II:
(i) Give one example of organism P and organism Q. [2 marks]

(ii) Describe the similarities and differences between the blood circulatory system in organism P and organism Q. [6 marks]


Answer:

(a)(i)

• Platelets clump together and produce thrombokinase.
• Thrombokinase converts prothrombin to thrombin.
• Thrombin converts fibrinogen (a type of soluble protein plasma) to fibrin (vitamin K is needed in the formation of prothrombin).
• Fibrin forms a network to trap the erythrocytes
• To form a clot

(a)(ii)

• Less red blood cells to combine with oxygen
• Less oxygen is transported to the body cells.
• Less energy is produced
• Resulting in tiredness/ pale looking appearance/ anaemia
• Need food which is rich in iron
• Examples: Cockles, liver, spinach

(b)(i)

P: Fish
Q: Human being

(b)(ii)

Similarities:

• Both have a closed circulation
• Blood flows in blood vessels