Cardiac cycle + blood vessels

Question 1

what is diastole

Answer 1

relaxing

Question 2

what is systole

Answer 2

contracting

Question 3

what are the bicuspid + tricuspid valves generally called

Answer 3

atrio-ventricular valves (AV valves)

Question 4

what are the aortic and pulmonary valves generally called

Answer 4

semi-lunar valves (SL valves)

Question 5

describe atrial systole

Answer 5

• atria contracts
• pressure greater in atria than ventricle
• blood flows into ventricle, fully filling it

Question 6

describe ventricular systole

Answer 6

• atria relaxes, ventricle contracts
• AV valve closes
• pressure greater in ventricle than aorta, SL valve opens
• blood flows into the aorta

Question 7

describe diastole

Answer 7

• ventricle relaxes
• pressure in aorta greater than ventricle
• SL valve closes
• AV valve opens
• blood flows from the atria into ventricle, passively refilling

Question 8

pressure graph cardiac cycle

Answer 8

FLASHCARD

Question 9

describe the structure of the arteries (4)

Answer 9

• thick muscle layer
• relatively thick elastic layer
• overall thickness of wall is large
• no valves (except in arteries leaving the heart)

Question 10

how does the structure of arteries relate to its function

Answer 10

+thick muscle layer- maintain high pressure flow to tissues (from heart)
+relatively thick elastic layer- stretch and recoil allow for high pressure flow
+overall thickness of wall is large- muscle can contract
+no valves- due to high pressure from stretch and recoil

Question 11

describe the structure of veins (4)

Answer 11

• overall thickness of wall is small
• muscle layer relatively thin
• elastic layer relatively thin
• contain valves at intervals throughout

Question 12

how does the structure of veins relate to its function

Answer 12

+overall thickness of wall is small, muscle layer + elastic layer thin (relatively)- slow, low pressure transport of blood (from tissues to heart)
+valves- prevent backflow of blood due to low pressure

Question 13

describe the structure of arterioles (3)

Answer 13

• muscle layer relatively thicker than in arteries
• elastic layer relatively thinner than in arteries
• smaller and more numerous than arteries

Question 14

how does the structure of arterioles relate to its function

Answer 14

+thicker muscle layer, thinner elastic layer (than arteries) - allow for vasodilation/vasoconstriction controlling blood flow to arteries
+smaller and more numerous than arteries - decreasing pressure, increasing speed of blood due to greater cross-sectional area

Question 15

describe the structure of capillaries (5)

Answer 15

• wall consists of mainly the internal lining layer (endothelium)
• numerous and highly branched
• pores (fenestrae) between endothelial cells
• narrow lumen
• narrow diameter

Question 16

size of capillary lumen

Answer 16

7um

Question 17

how does the structure of capillaries relate to its function

Answer 17

+lining layer (endothelium)- very thin, reduced diffusion distance between blood and body cells
+numerous, highly branched- large SA for gas exchange
+fenestrae- for formation of tissue fluid
+narrow lumen- red blood cells closer to cells (reduce diffusion distance)
+narrow diameter- squeeze between tissues so all cells very close to capillaries (reduces diffusion distance)

Question 18

what solute is found in the capillaries

Answer 18

plasma proteins

Question 19

describe features of the arterial end (in relation to water potential)

Answer 19

• higher hydrostatic pressure than venous end
• lower solute (plasma protein) concentration than venous end
• higher water potential than outside capillary- so a net movement of water out of the capillary

Question 20

describe the features of the venous end (in relation to water potential)

Answer 20

• lower hydrostatic pressure than arterial end
• higher solute (plasma protein) concentration than arterial end
• lower water potential than outside capillary- net movement of tissue fluid into the capillary

Question 21

what happens to some of the tissue fluid when inside the tissues

Answer 21

a small portion of it is drained into the lymph vessels then moves back into the circulatory system. (Allows for products of tissue cells to be carried into the bloodstream)

Question 22

function of tissue fluid

Answer 22

contains dissolved materials such as glucose. cells can exchange materials with the tissue fluid

Question 23

where does tissue fluid come from

Answer 23

it is water from blood plasma

Question 24

why do all blood vessels have a thin endothelial lining

Answer 24

to reduce friction

Question 25

why do all blood vessels have a tough, fibrous outer layer

Answer 25

to resist pressure changes from inside and outside

Question 26

pressure graph blood flow

Answer 26

FLASHCARD