[OLD] the heart

Question 1

what happens during atrial and ventricular diastole?

Answer 1

atria and ventricles are relaxed
atria and ventricles fill passively
AV valves are open, semilunar valves are closed

Question 2

what happens during atrial systole

Answer 2

the semilunar valves are closed and the AV valves are open

both atria contract, forcing blood to the ventricles

Question 3

what happens during ventricular systole?

Answer 3

both ventricles contract simultaneously
the AV valves close
the semilunar valves open and blood enters the pulmonary trunk and aorta.

Question 4

cardiac cycle

Answer 4

atrium, AV valves are closed
atrium contract, raising pressure and opening valves, ventricles
ventricles contract when full, raising pressure and closing AV valves
ventricles continue to contract, opening semilunar valves, arteries
higher pressure in arteries closes semilunar valves

Question 5

what do arteries do?

Answer 5

carry blood away from the heart at high pressure

Question 6

why do arteries have a narrow lumen?

Answer 6

to maintain pressure

Question 7

what do the arteries walls contain?

Answer 7

collagen
elastic tissue
smooth muscle
folded endothelium

Question 8

what does collagen do?

Answer 8

provides strength to withstand pressure

Question 9

what does elastic tissue do?

Answer 9

allows walls to stretch and recoil to maintain pressure

Question 10

what does smooth muscle do?

Answer 10

contact to constrict lumen to maintain pressure

Question 11

what does folded epithelium do?

Answer 11

squamous epithelium to provide a smooth surface to reduce friction and folded to allow stretch

Question 12

what are the two types of artery?

Answer 12

elastic and muscular

Question 13

examples of elastic arteries

Answer 13

aorta, pulmonary artery

Question 14

in which of the four chambers does pressure reach the highest value?

Answer 14

the left ventricle

Question 15

how does the structure of the left ventricle cause a high pressure?

Answer 15

it has a thick muscular wall

Question 16

how do you find heart rate?

Answer 16

60/(time taken for one cardiac cycle) = heart rate in bpm

Question 17

how do you calculate cardiac output?

Answer 17

Stoke volume X heart rate

Question 18

what is Stroke volume?

Answer 18

the different between the highest and the lowest volume of blood in a cardiac cycle

Question 19

how do elastic fibres help to smooth out blood pressure?

Answer 19

the elastic fibres stretch and absorb the shock waves caused by the hearts forceful pumping action. the fibres recoil to their original length between heartbeats

Question 20

why is blood leaving the heart through the aorta at a higher pressure than blood leaving through the pulmonary artery?

Answer 20

the walls of the left ventricle are thick than the walls of the right ventricles and so exert more force

Question 21

risk factors associated sign coronary heart disease

Answer 21

increased age
smoking
obesity
high cholesterol diet
genetics

Question 22

what is the hepatic portal vein?

Answer 22

the vein from the small intestine to the liver

Question 23

differences between structure of veins and arteries

Answer 23

arteries have thicker walls
veins have valves, arteries don't
Arteries have more muscle
arteries have narrower lumen
arteries have more elastic fibres

Question 24

HOWdoes smooth muscle reduce blood flow to the small intestine

Answer 24

smooth muscle can contract which will reduce the diameter of the lumen, restricting blood flow

Question 25

how does elastic tissue help to even out the pressure of blood through blood vessels

Answer 25

the elastic fibres absorb. the force of the heart beat by stretching. the fibres recoil to their original length between heartbeats. t his smooths out the changes in pressure

Question 26

how is plasma different from tissue fluid?

Answer 26

plasma has large proteins in it

Question 27

what. amuses the. look pressure to decrease along the length of the capillary

Answer 27

fluid is forced out of the capillary

Question 28

how can low concentrations of plasma cause accumulation of tissue fluid?

Answer 28

for water to be reasoned by osmosis and the venule end of the capillary t he water potential needs to be lower inside the capillary. this will not happen if there is inadequate protein in the plasma. tissue fluid will accumulate and not be reabsorbed

Question 29

what is meant by a quaternary structure?

Answer 29

a protein with 2 or more polypeptide chains

Question 30

why is isotonic salt solution used to dilute blood samples?

Answer 30

to examine cells under a microscope a solution is used to prevent the cells from dehydrating. an isotonic solution has the same water potential as the cell cytoplasm, so the cells will not be damaged by osmosis, which would burst them if just water was added.