Chapter 20 questions
1. The micrograph below (figure 12) shows human blood.
(a) Identify the cells labeled I and II.
ii) The lymphocyte has a defined and rounded nucleus while the erythrocyte does not have any.
(b) Distinguish the cells labeled II and III.
Cell III corresponds to a phagocyte, because it has a lobed nucleus while the lymphocyte has a rounded and whole nucleus as said before.
(c) (I) The actual diameter of the erythrocytes is 7 µm. Calculate the magnification of the micrograph.
= x 1571
(ii) Using this magnification, calculate the actual diameters of the largest and smallest leucocytes in the micrograph.
2) To pump blood, the heart goes through a series of action, called the cardiac cycle. These actions are listed below in alphabetical order. Arrange them in the correct sequence, starting with the contraction of the atria. Some actions happen simultaneously.
• Atria start to contract.
• Blood is pumped from the atria to ventricles.
• Ventricles start to contract.
• Atrioventricular valves close.
• Seminular valves open.
• Blood is pumped from ventricles to arteries.
• Atria start to fill with blood.
• Seminular valves close.
• Atrioventricular vales open.
• Ventricles start to fill with blood.
3) State where
(I) Carbon dioxide is removed from the blood.
(II) Oxygen diffuses into the blood.
(III)Oxygen diffuses out of the blood
The respiring tissues
(IV) Glucose and other nutrients enter the blood.
The small intestine.
(V)Hormones enter the blood
(VI)urea is removed from the blood
b) (I) suggest two parts of the body where blood usually looses thermal energy.
The lungs, skin, and rectum.
(II) Suggest one part of the body where blood usually gains thermal energy.
(c)Suggest one component of blood plasma that increases in...