1.1 Cardiovascular disease

Question 1

What is positive feedback?

Answer 1

The enhancing or amplification of an effect by its own influence on the process which gives rise to it.

Question 2

What is atherosclerosis?

Answer 2

The disease process that leads to coronary heart disease and strokes where fatty deposits can block and artery or increase the chances of a blood clot.

Question 3

What is thrombosis?

Answer 3

An artery being blocked by a blood clot.

Question 4

What are the first two processes in atherosclerosis?

Answer 4

1 - The endothelium becomes damaged
2 - Inflammatory response: white blood cells move into the artery wall and accumulate chemicals from the blood, particularly cholesterol. An atheroma builds up.

Question 5

What are the last two processes in atherosclerosis?

Answer 5

3 - Calcium salts and fibrous tissue build up, resulting in a hard swelling called a plaque.
4 - Plaques cause the lumen to narrow and causes high blood pressure.

Question 6

What is an atheroma?

Answer 6

A fatty deposits that build up in atherosclerosis.

Question 7

What happens first when a blood vessel is damaged?

Answer 7

Platelets come into contact with the damaged vessel wall and change shape into spheres with long thin projections. This sticks them to the exposed collagen and each other to form a temporary platelet plug.

Question 8

What are the first two processes in the clotting cascade?

Answer 8

1 - platelets and damaged tissue release a protein called thromboplastin.
2 - This activates an enzyme that catalyses the conversion of prothrombin to thrombin. Protein factors, vitamin K and calcium ions must be present for this to happen.

Question 9

What are the last two processes of the clotting cascade?

Answer 9

3 - Thrombin catalyses the conversion of fibrinogen (soluble) into fibrin (insoluble).
4 - A mesh of fibrin forms that traps more platelets and red blood cells to form a clot.

Question 10

What do unicellular organisms use to move substances?

Answer 10

diffusion

Question 11

why do multicellular organisms need a circulatory system?

Answer 11

they rely on a mass transport system to move substances around by mass flow

Question 12

describe an open circulatory system

Answer 12

a simple heart pumps blood out into cavities surrounding the animals organs, substances can diffuse between the blood and cells

Question 13

describe a closed circulatory system

Answer 13

blood is enclosed within blood vessels, the blood flowed along arteries then arterioles to capillaries. the blood then returns to the heart through veins and venules

Question 14

what are the advantages of an open circulatory system?

Answer 14

requires less energy for distribution
suited for slow metabolisms and small bodies

Question 15

what are the disadvantages of an open circulatory system?

Answer 15

almost impossible to increase blood distribution as the total capacity of the system is achieved with virtually every heart beat

Question 16

what are the advantages of a closed circulatory system?

Answer 16

large concentration gradients over long distances which allows more complex organisms to evolve

Question 17

what are the disadvantages of a closed circulatory system?

Answer 17

the pressure that is possible is limited because of damage to the exchange organ

Question 18

what are the two types of closed circulatory system?

Answer 18

single and double

Question 19

describe a single circulatory system in a fish

Answer 19

the heart pumps deoxygenated blood to the gills so gaseous exchange takes place in the gills through diffusion then the blood flows around the body back to the heart

Question 20

describe a double circulatory system

Answer 20

the right ventricle pumps deoxygenated blood to the lungs then the blood returns to the heart to be pumped to the body

Question 21

what is the advantage of a double circulatory system?

Answer 21

the pressure delivering blood to the body tissues can be higher than that delivering blood to the exchange surface

Question 22

what are the advantages of higher pressure to the body tissues

Answer 22

faster delivery of nutrients and removal of wastes
maintains concentration gradients
enables higher metabolic rates
enables size of organisms to be larger

Question 23

why is chemicals dissolving easily important for water in the body

Answer 23

allows vital biochemical reactions to occur in the cytoplasm

Question 24

why is having a high shc important for water in the body

Answer 24

water can absorb large amounts of heat energy before its temperature raises a significant amount so this helps organisms to avoid rapid changes in their internal temperature even when their surroundings varies

Question 25

describe the blood flow of the vena cava

Answer 25

deoxygenated blood into the right atrium

Question 26

describe the blood flow in the aorta

Answer 26

oxygenated blood from the left ventricle to the body

Question 27

describe the blood flow in the pulmonary veins

Answer 27

oxygenated blood from the lungs into the left atrium

Question 28

what is the advantage of arteries having thick smooth muscular walls?

Answer 28

maintain higher pressure without damage

Question 29

what is the advantage of arteries having elastic fibre tissue?

Answer 29

elastic stretch to accommodate higher pressure and recoil to maintain high pressure

Question 30

what is the advantage of arteries having a folded endothelium?

Answer 30

allows stretching to accommodate high pressure

Question 31

what is the advantage of arteries having a narrow lumen?

Answer 31

maintains blood pressure

Question 32

what is the advantage of arteries having smooth lining/endothelium?

Answer 32

reside friction/resistance

Question 33

what is the advantage of arteries having collagen?

Answer 33

avoids damage

Question 34

what is the advantage of veins having thinner walls?

Answer 34

allow skeletal muscle movement and low pressure to draw blood back to heart

Question 35

what is the advantage of veins having the presence of valves?

Answer 35

ensures blood continues to move towards heart

Question 36

what is the advantage of veins having a large lumen?

Answer 36

blood flows back to heart under low pressure

Question 37

what is the advantage of capillaries having very thin walls?

Answer 37

reduces diffusion distance/higher rate of diffusion

Question 38

what is the advantage of capillaries having a large network near all cells of a tissue?

Answer 38

increase surface are/ higher rate of diffusion

Question 39

what is the advantage of capillaries having a lumen wide enough for one red blood cell?

Answer 39

reduces diffusion distance between RBCs and tissue cells

Question 40

How is the heart muscles supplied with blood?

Answer 40

Through the coronary arteries, a network of capillaries and two coronary veins

Question 41

What are phase 1,2 and 3 of of the cardiac cycle?

Answer 41

atrial systole, ventricular systole and cardiac diastole

Question 42

what happens during the atrial systole?

Answer 42

blood flows into the atria causing the atrioventricular valves to push open and leak blood into the ventricles. the atria walls contract forcing more blood into the ventricles.

Question 43

what happens during the ventricular systole?

Answer 43

the ventricles contract from the base of the heart upwards which pushes the semilunar valves open causing blood to move up through the pulmonary arteries and aorta. the pressure of the blood closes the atrioventricular valves.

Question 44

what happens during cardiac diastole?

Answer 44

the atria and ventricles relax me recoil of the heart walls lower the pressure. the semi lunar valves close.

Question 45

what is coronary heart disease?

Answer 45

narrowing of coronary arteries increasing risk of myocardial infarction