transport in humans

Question 1

what are the components of blood?

Answer 1

1. plasma
2. red blood cells
3. white blood cells
4. platelets

Question 2

what are the adaptations of red blood cells?

Answer 2

1. contains pigment haemoglobin which is a iron-containing protein that combines reversibly with oxygen
2. circular flattened biconcave disc –> increases surface area to volume ratio –> cell can absorb and release oxygen at faster rate
3. does not posses a nucleus –> carry more haemoglobin
4. elastic and can turn bell-shaped in order to squeeze through blood vessels

Question 3

what are the features of white blood cells?

Answer 3

1. colourless and does not contain haemoglobin
2. irregular in shape and contains a nucleus
3. it can move, change its shape and squeeze through the walls of the thinnest blood capillaries into spaces among tissue cells

Question 4

what are the 2 kinds of white blood cells?

Answer 4

1. lymphocyte
2. phagocyte

Question 5

why/how does blood clot?

Answer 5

• blood exposed to air will soon clot
• the clot seals the wound, preventing excessive loss of blood
• prevents foreign particles from entering the bloodstream

Question 6

what is phagocytosis?

Answer 6

phagocytosis is the process of engulfing or ingesting foreign particles such as bacteria by white blood cells

Question 7

what is the function of white blood cells?

Answer 7

produce antibodies
- antibodies destroy bacteria
- cause bacteria to clump together so that they can be easily ingested by phagocytes

Question 8

characteristics of artery

Answer 8

• thick, muscular walls to withstand high pressure of blood as it is forced out of the heart
• elastic walls allow artery wall to stretch and recoil –> pushes the blood in spurts along the artery

Question 9

characteristics of veins

Answer 9

• thin walls as the blood pressure in the veins is much lower than the blood pressure in the arteries
• have internal valves to prevent backflow of blood

Question 10

function of arteries

Answer 10

carry blood away from heart

Question 11

function of veins

Answer 11

carry blood towards the heart

Question 12

why does the right ventricle have thinner walls as compared to left ventricle?

Answer 12

• right ventricle only has to pump blood to the lungs, which is relatively close to the heart
• left ventricle has to pump blood around the whole body –> requires high pressure

Question 13

what is the pathway of blood in the heart?

Answer 13

vena cava –> right atrium –> right ventricle –> pulmonary artery –> lungs –> pulmonary vein –> left atrium –> left ventricle –> aorta –> other parts of the body

Question 14

causes of coronary heart disease

Answer 14

1. diet rich in cholesterol and saturated animal fats
2. emotional stress
3. smoking

Question 15

preventive measures against coronary heart disease

Answer 15

1. proper diet
2. proper stress management
   3.regular physical exercise
3. abstain from smoking