heart and blood vessels

Question 1

explain A- start

Answer 1

The left ventricle contracts; its volume decreases and the pressure inside increases above the pressure in the atrium, so the atrio-ventricular valve loses.

Question 2

explain B- increasing

Answer 2

the semilunar valve opens when the pressure in the ventricle is greater than that in the aorta, blood flows into the aorta

Question 3

explain C- start of decrease

Answer 3

ventricle relaxes and the semilunar valve closes as pressure in the aorta exceeds that in the ventricle

Question 4

explain c- bottom of decrease

Answer 4

pressure inside the ventricle falls below that in the atrium. the atrium contracts, producing a small pressure. the atrio-ventricular valve then opens, allowing blood to flow into the ventricle

Question 5

what is cardia output?CO

Answer 5

the volume of blood pumped out of one ventricle per minute

Question 6

what is stroke volume S0

Answer 6

the volume of blood expelled from the left ventricle of the heart per contraction

Question 7

what is heart rate? HR

Answer 7

number of contractions per minute

Question 8

equation of CO

Answer 8

cO=SV X HR

Question 9

blood flows away from the heart in what?

Answer 9

arteries at high blood pressure

Question 10

explain arteries properties

Answer 10

a thick wall and a smaller lumen containing elastic fibres and smooth muscle tissie to withstand the high pressures. they carry oxygenated blood

Question 11

explain arterioles

Answer 11

contraction of the smooth muscle causing narrowing (vasoconstriction) of the arteriole, reducing blood flow to the capillaries. relaxation of the smooth muscle causes widening (vasodilation) pf the arteriole, increasing blood flow to the capillaries

Question 12

what do veins do

Answer 12

carry low pressure blood to the heart

Question 13

explain semi lunar valves in veins

Answer 13

upward pressure of the blood forces the valve open and blood flows towards the heart. backflow of blood closes the valve, which resembles a pocket when full of blood

Question 14

explain properties of capillaries

Answer 14

1 endothelial cell thick, giving a short diffusion pathway for the exchange of substances with the tissues. large number of capillaries to increase exchange with tissues. the total cross sectional areas of capillaries is very high producing a large frictional resistance, allowing more time for diffusion.

Question 15

when does coronary heart disease occur?

Answer 15

when coronary arteries have lots of atheroma’s in them , restricting blood flow to the heart

Question 16

term for heart attack?

Answer 16

mycocardial infarction

Question 17

whats an atheroma, its cause and problem?

Answer 17

a build up of fat and cholesterol in the wall of thr arteries caused by high saturated fat diet. Can cause hardened plaque to form and the plaque grows and blocks the lumen

Question 18

whats an thrombosis, its cause and problem?

Answer 18

formation of blood clots. caused by smoking/ bursting of atheroma. may cause blocking of blood vessels

Question 19

whats an aneurysm, its cause and problem?

Answer 19

a balloon like swelling in arteries which may burst, leading to a haemorrhage. caused by atheroma’s may weaken the artery wall causes a swelling to form. problem Is that increased blood loss and reduced blood flow to cells.

Question 20

what happens if blockage occurs in the coronary arteries?

Answer 20

a reduced blood flow to the heart and cells, reduced oxygen supply to the heart, heart muscles will respire less releasing less ATP so cells die causing a heart attack

Question 21

risk factors for cardiovascular disease?

Answer 21

• diet high in saturated fats/ cholesterol
• high blood cholesterol
• high salt consumption
• smoking
• lack of exercise
• obesity
• age
• high blood pressure
• sex
• ethnicity

Question 22

reducing the risk of CVD?

Answer 22

• quit/reduce smoking
• exercise regularly
• lower saturated fat consumption
• lower salt consumption

Question 23

capillaries supply cells with what? what do they remove?

Answer 23

oxygen, amino acids, mineral ions, hormones and remove waste products of metabolism eg carbon dioxide and urea

Question 24

how is tissue fluid produced?

Answer 24

at the arteriole end of a capillary, the blood or hydrostatic pressure is high. this pressure causes the filtration of plasma containing water, glucose, amino acids, minerals and hormones through the permeable capillary wall. the blood cells and larger plasma proteins remain in the capillary. the filtered plasma forms tissue fluid.

Question 25

what is hydrostatic pressure

Answer 25

comes from ventricle contraction. falls along the capillary due to resistance from capillary walls

Question 26

what is osmotic pressure

Answer 26

water potential of tissue fluid is higher than water potential of blood.

Question 27

what do lymph capillaries do?

Answer 27

absorb the excess tissue fluid transported in lmph vessels

Question 28

what do plasma porteins in the blood do?

Answer 28

reduce water potential

Question 29

what happens at the venous end?

Answer 29

the hydrostatic pressure is reduced and some of the filtered plasma is reabsorbed by osmosis.