transport system in humans

Question 1

What are the components of blood (tissue)?

Answer 1

Plasma, white blood cells and blood platelets, red blood cells

Question 2

What is plasma?

Answer 2

Plasma is a pale yellowish liquid. It consists of 90% water and the rest (10%) are digested food substances, mineral salts, excretory waste products, and proteins such as hormones.

Question 3

What is the function of plasma?

Answer 3

Plasma acts as a transport medium, carrying digested food and mineral salts from the small intestine to other parts of the body, excretory waste products from all parts of the body to the excretory organs for removal, and hormones from the glands to the target organs.

Question 4

What are the adaptations of red blood cells?

Answer 4

1. RBCs contain haemoglobin, which can combine reversibly with oxygen, allowing RBCs to transport oxygen from the lungs to all cells of the body.
2. RBCs have a flattened, circular, biconcave disc shape, which increases the surface area to volume ratio of the RBC, allowing for faster diffusion of oxygen in and out of the RBC.
3. RBCs are elastic and can turn bell-shaped. This allows RBCs to be able to squeeze through blood vessels smaller than itself in diameter.
4. RBCs do not contain a nucleus. This allows for more room to store haemoglobin, allowing more oxygen to be transported.

Question 5

Why is it helpful for athletes to train 3000 - 4000 metres above sea level?

Answer 5

These athletes will have an increased proportion of red blood cells in their body. By having a larger number of red blood cells, these athletes will have more energy bring transported to their tissue cells per unit time. Thus, their rate of cellular aerobic respiration increases, which releases more energy for muscular contraction.

Question 6

What is the function of blood platelets?

Answer 6

Blood platelets aid in blood clotting and are involved with the repair of damaged blood vessels that arise from cuts and wounds. The blood clot seals the cut, minimising blood loss and preventing entry of microorganisms.

Question 7

Why is the shape of the white blood cell irregular?

Answer 7

The WBC has an irregular shape as it has a flexible cell surface membrane to allow the phagocyte to change its shape to engulf foreign particles.

Question 8

How does the structure of the capillary benefit the capillary?

Answer 8

1. The endothelium is one cell thick and is partially permeable. This allows certain substances to diffuse quickly through the capillary walls.
2. The capillary branches repeatedly. This increases the area for the exchange of gases between the blood and tissue cells.
3. The capillary has a large total cross-sectional area. This lowers the blood pressure in the capillaries, allowing the blood to move slower through the capillaries, allowing for more time for the exchange of substances to take place.

Question 9

Which ventricle of the heart has thicker muscular walls and why?

Answer 9

The right ventricle has thinner muscular walls than the left ventricle since it only pumps blood to the lungs, which is close to the heart and does not require high pressure.
The left ventricle has thicker muscular walls than the right ventricle as it has to pump blood around the whole body, which requires high pressure.