topic 1

Question 1

define open circulatory system

Answer 1

is where the heart pumps blood into cavities were substances diffuse. when the heart relaxes blood is drawn back

Question 2

define closed circulatory system

Answer 2

blood enclosed within tubes generates higher blood pressure. blood travels faster under pressure. large amount of capillaries increase exchange. valves in veins

Question 3

define single circulatory system

Answer 3

heart –> gills –> body –> heart

slow

Question 4

define a double circulatory system

Answer 4

heart –> lungs –> heart –> body –> heart

reduces time taken to get around body. increases metabolic rate.

Question 5

arterys

Answer 5

narrow lumen, thick walls, more collagen, smooth muscle, elastic fibres in wall no values.
when blood enters arteries the elastic walls stretch to accommodate it. high pressure. when the heart relaxes the elastic walls recoil behind blood pushing it forwards.

Question 6

cappilaries

Answer 6

tiny lumens, epithelium one cell think.
blood flow more slowly here as the narrow lumens cause friction between the blood and the walls. this allows gas exchange between the blood and surrounding cells. capillaries lies close to every cell ensuring rapid diffusion

Question 7

veins

Answer 7

wide lumens, thinner walls, less collagen, smooth muscle, elastic fibres, valves. low blood pressure.
steady flow without pulses.
blood flow assisted by body movement. black flow is prevented by semilunar valves.

Question 8

collagen

Answer 8

a tough fibrous proteins which makes them strong and durable

Question 9

stages in heart pumping

Answer 9

1. atrial systole
2. ventricular systole
3. cardiac diastole

Question 10

what happens in atrial systole

Answer 10

first stage
blood returns to heart. there is low blood pressure. atria fills increasing pressure, atrioventrical valves open as atria contract blood flows in to ventricles

Question 11

what happens in ventricular systole

Answer 11

second stage
slight delay ventricles contract increasing pressure. forcing semilunar valves open pushing blood into pulmanary arteries and aorta. antriventrical values close stopping back flow

Question 12

what happens in cardiac diastole

Answer 12

third stage
atria and ventricles relax. semilunar valves close preventing back flow. coronary arteries fill. low pressure in arota draws blood from veins.

Question 13

flow diagram of how blood flows in the left side of the heart

Answer 13

pulmonary veins - left atrium - through atrioventricular valve - left ventricle - through semi lunar valves - into aorta - bodies - inferor and superor vena cavar

Question 14

flow diagram of how blood flows in the right side of the heart

Answer 14

inferor and superor vena cavar - right atrium - through atrioventricular valve - right ventricle - through semi lunar valve - pulmonary artery - lungs - pulmonary veins

Question 15

what is plasma

Answer 15

the liquid that carries the red blood cells and other cells. it is mainly water but also contains O2 CO2, proteins, amino acids, salts, enzymes, hormones, antibodies, urea, red and white blood cells and platlets.

Question 16

stages in atherosclerosis

Answer 16

1. endothelium becomes damaged and dysfunctional
2. inflamatory response
3. plaque is formed
4. lumen becomes narrower
5. feedback

Question 17

what happens in stage 1 of atherosclerosis

Answer 17

edothelium becomes damaged and dysfunctional. resulting in high blood pressure. putting extra strain on cells.

Question 18

what happens in stage 2 of atherosclerosis

Answer 18

inflamatory response
white blood cells move into artery wall. they accumalate chemicals such as cholesterol. a fatty deposit builds up called an atheroma

Question 19

what happens in stage 3 of atherosclerosis

Answer 19

plaque is formed:
calcium salts and fibrous tissue build up at the site resulting in hard swelling called plaque. artery wall loses elasticity and hardens.

Question 20

what happens in stage 4 of atherosclerosis

Answer 20

lumen becomes narrower:
making it more difficult to pump blood
and leads to a rise in blood pressure

Question 21

what happens in stage 5 of atherosclerosis

Answer 21

feedback

plaque –> rise in blood pressure —> damage to edothelium —> plaque

Question 22

what are the stages in the blood clotting cascade

Answer 22

1. plaque reptures exposing collagen to the blood
2. platelets and damage tissue release a protein called thromboplastin
3. thromboplastin activates enzyme that catalyses convertion of protein prothrombin into enzyme called thrombin. protein, vitamin k and calcium must be present
4. thrombin then catalyses conversion of soluble plasma protein, fibrinogen insoluble fibrin.
5. a mesh of fibrin forms that traps more platelets and red blood cells to form a clot.

Question 23

what is the role of blood clots in heart disease

Answer 23

• blood clots block artieries
• reducing blood flow to heart tissue
• resulting in a heart attack.

Question 24

coronary heart disease

Answer 24

narrowing of cornonary arteries limits blood reaching heart muscles, angina chest pain experienced during exertion when the heart if forced to respire anaerobically.

Question 25

coronary heart disease sometimes results in a heart attack. explain what that is

Answer 25

myocardial infraction heart attack.
fatty plaque ruptures exposing collagen resulting in blood clot that may block the blood supply completely. the heart muscle receives no blood and arterie is said to be ischaemic. muscle cells starved of oxygen for too long are permanently danged.

Question 26

what happens in a stroke

Answer 26

blood supply to the brain is interrupted.
a mini stroke is when it is only briefly interrupted. all symptoms but only for a short period and recovery is quicker.
if the blood clot completely obstructs the artery a full stroke will occur. if the brain cells are deprived of oxygen for a few minutes they will be permanently damaged.