Transport in Humans

Question 1

what is the heart?

Answer 1

• muscular pump
• drives blood around the body

Question 2

types of blood vessels

Answer 2

• arteries
• capillaries
• veins

Question 3

what is the blood made off?

Answer 3

• 55% plasma
• red blood cells
• white blood cells
• platelets

Question 4

what is a double circulatory system?

Answer 4

a system where blood flows through the heart twice in one circuit

Question 5

what is the advantage of a double circulatory system?

Answer 5

• pumps blood at low pressure to lungs to be properly oxygenated
• pumps blood at high pressure to the rest of the body
• no mixing of oxygenated and deoxygenated blood

Question 6

what is pulmonary circulation?

Answer 6

• oxygenated blood from lungs to heart
• deoxygenated blood from heart to lungs

Question 7

what is systemic circulation?

Answer 7

• oxygenated blood from heart to the rest of the body except lungs
• deoxygenated blood from the rest of the body to the lheart

Question 8

blood vessels at the liver are called?

Answer 8

hepatic blood vessels + hepatic portal vein

Question 9

blood vessels at the kidneys are called?

Answer 9

renal blood vessels

Question 10

what are the main functions of blood?

Answer 10

• to transport food substances, waste substances, oxygen and hormones and heat
• to protect the body by fighting off infections and foreign bodies

Question 11

what are the adaptations of red blood cells and their functions?

Answer 11

• contains haemoglobin - to bind reversibly with oxygen to carry oxygen
• circular and biconcave - to increase surface area to volume ratio for quicker diffusion of oxygen
• no nucleus - to store more haemoglobin in cytoplasm to carry more oxygen
• flexible and elastic cell surface membrane - to change shapes and easily squeeze through capillaries

Question 12

what are the functions of platelets?

Answer 12

• to prevent further blood loss
• to prevent any pathogens from entering the body through the wound

Question 13

steps to blood clotting

Answer 13

1. damaged tissue and platelets from thrombokinase
2. thrombokinase and calcium ions activate prothrombin to form thrombin
3. thrombin catalyzes fibrinogen to fibrin threads
4. fibrin threads trap red blood cells

Question 14

what is agglutination?

Answer 14

the clumping of red blood cells which is fatal

Question 15

what are antigens?

Answer 15

a protein marker found on the cell surface membrane

Question 16

what are antibodies?

Answer 16

a y-shaped protein that is complementary to the shape of a specific antigen and binds to it

Question 17

what are the three layers of artery and vein walls?

Answer 17

1. inner: endothelium
2. middle: elastic fibres and smooth muscle tissues
3. outer: connective tissues

Question 18

special features of arteries and their functions

Answer 18

• thick elastic and muscular walls to withstand high blood pressure
• thick elastic walls to stretch and recoil, pushing the blood along in spurts, maintaining a high pressure

Question 19

special features of veins and their functions

Answer 19

• semilunar valves to prevent the backflow of blood
• muscles contract to push along the vein to the heart

Question 20

features of capillaries and their functions

Answer 20

• one cell thick partially permeable wall wall faster diffusion of certain substances
• branches repeatedly for a greater surface area to volume ratio for quick exchange of substances

Question 21

what does tissue fluid contain?

Answer 21

• glucose
• amino acids
• urea
• hydrogencarbonate ions

Question 22

which sides of the heart receives oxygenated and or deoxygenated blood?

Answer 22

left side: oxygenated
right side: deoxygenated

Question 23

function of the septum

Answer 23

separates the left and right side of the heart to prevent oxygenated and deoxygenated blood from mixing

Question 24

function of heart valves

Answer 24

to ensure blood flows in the undirectionally and not backflow

Question 25

what happens in atrial systole?

Answer 25

1. Atrial pressure is higher than ventricular pressure.
2. Bicuspid valve is open to allow blood to flow.
3. Blood therefore flows from left atrium to left ventricle, down its pressure gradient.
4. Aortic pressure higher than ventricular pressure.
5. Semi-lunar valves close to prevent backflow of blood from aorta into left ventricle

Question 26

what happens in ventricular systole?
(+ atrium diastole)

Answer 26

1. Ventricular pressure rises such that it is higher than aortic pressure.
2. Semi-lunar valves open to allow blood to flow through.
3. Blood flows from left ventricle into the aorta
4. Meanwhile, atrium undergoes diastole and begins to be filled with blood.
5. Bicuspid valve closes to prevent backflow of blood from ventricle to atrium.

Question 27

what happens in ventricular diastole?

Answer 27

1. Ventricular pressure decreases until it is lower than aortic pressure.
2. Semi-lunar valves close to prevent backflow of blood from aorta into left ventricle.
3. Ventricular pressure decreases further until it is lower than atrial pressure.
4. Bicuspid valve opens to allow blood to flow.
5. Blood therefore flows from left atrium to left ventricle, down its pressure gradient.
6. The cycle repeats.

Question 28

function of coronary arteries

Answer 28

supply nutrients and oxygen to the heart

Question 29

process of heart attack

Answer 29

• build up of fatty deposits and cholesterol
• coronary artery narrowed and blocked
• no blood, nutrients and oxygen supplied to heart
• heart cannot respire and dies

Question 30

causes of coronary heart disease

Answer 30

• stress
• smoking
• poor diet
• lack of exercise

Question 31

preventive measures against coronary heart disease

Answer 31

• regular exercise
• reduce smoking
• manage stress
• healthier diet (less cholesterol and animal fats intake)