Chapter 6: Transport in humans

Question 1

What is the yellowish liquid in blood?

Answer 1

Plasma

Question 2

What does plasma contain?

Answer 2

Mainly water, blood cells, excretory products, nutrients, hormones

Question 3

What is the primary function of red blood cells (RBC)?

Answer 3

To transport oxygen from the lungs to other parts of the body

Question 4

What does RBC consist mostly of?

Answer 4

Haemoglobin with reversibly combines with oxygen to oxyhaemoglobin

Question 5

What are the 3 characteristics of the RBC?

Answer 5

Biconcave shapes, no nucleus and flexible

Question 6

Why does the RBC have a biconcave shape?

Answer 6

To increase the surface area to volume ratio , increasing the rate of diffusion of oxygen in and out of the cell

Question 7

Why does the RBC have no nucleus?

Answer 7

For more space available for haemoglobin (increasing the amount of oxygen transported)

Question 8

Why are RBC flexible?

Answer 8

So it can move easily through narrow capillaries

Question 9

What are the 2 types of white blood cell (WBC)?

Answer 9

Phagocyte and Lymphocyte

Question 10

What does the phagocytes do?

Answer 10

engulf and destroy pathogens (phagocytosis)

Question 11

What does the lymphocytes do?

Answer 11

produce antibodies (destroy pathogens, clump pathogens up, neutralise toxins produces by bacteria)

Question 12

What do platelets do?

Answer 12

Contains an enzyme that catalyses the conversion of fibrinogen to fibrin threads, which then entangles with RBC to form clot, stopping the bleeding

Question 13

What are the adaptations of arteries?

Answer 13

• Thick and muscular walls to withstand the high pressure of blood flowing within
• elasticity to help stretch and recoil
• contraction and relaxation to divert blood to other organs

Question 14

What are the adaptations of veins?

Answer 14

• Transport blood back to the heart
• walls are thinner than veins as blood flow is slower
• valves present to prevent backflow of blood

Question 15

What are the adaptations of capillaries?

Answer 15

• large surface area
• short diffusion distance
• steep concentration gradient

Question 16

Explain the process of blood flow in the heart. (Based on the common graph tested)

Answer 16

1. Increase in ventricular pressure due to the contraction of the left atrial muscles, forcing blood into the ventricle
2. Ventricular muscles begin to contract (bicuspid valve closes)
3. Ventricular muscles continue to contract, without change in volume of blood (pressure continues to rise)
4. Pressure in ventricle is higher than in aorta, so aortic valve (SL valve) opens, the pressure decreases as blood is forced into the aorta
5. Ventricular muscles relax without change in volume of blood
6. Bicuspid valve opens when the pressure in the ventricle is lower than in the atrium
7. Pressure in ventricle rises as blood enters ventricle from atrium

Question 17

What causes coronary heart disease?

Answer 17

Fatty deposits in the coronary arteries. (restricting blood flow)