Exchange and Mass Transport - Cardiac System

Question 1

What are the 3 stages of the cardiac cycle?

Answer 1

Diastole

Atrial Systol

Ventricular Systol

Question 1

What is diastole?

Answer 1

the stage of the cardiac cycle when all chambers are relaxed

Question 2

What is atrial systole?

Answer 2

contraction of the atria

allows blood to flow from the atria into the ventricles

Question 3

What is ventricular systole?

Answer 3

the contraction of the ventricles

allows blood to flow from the ventricles into the aorta or pulmonary artery

Question 4

What is the structure of the atria?

Answer 4

tissue is elastic to stretch as blood flows in

Question 5

What is the structure of the ventricles?

Answer 5

thick muscular walls

left ventricle has thicker walls than right because it pumps blood to the rest of the body, not the lungs

Question 6

Which organ carries deoxygenated blood into the heart?

Answer 6

vena cava

Question 7

Which organ carries deoxygenated blood out of the heart?

Answer 7

pulmonary artery

Question 8

Which organ carries oxygenated blood into the heart?

Answer 8

pulmonary vein

Question 9

Which organ carries oxygenated blood out of the heart?

Answer 9

aorta

Question 10

What are the semi-lunar valves?

Answer 10

Valves controlling the flow of blood into the pulmonary artery

Question 11

What is the valve between the atrium and ventricle?

Answer 11

left/right atrioventricular valve

Question 12

Which atrioventricular valve is bicuspic?

Answer 12

Left

Question 13

What is a bicuspic valve?

Answer 13

a valve with two leaflets

Question 14

Which atrioventricular valve is tricuspic?

Answer 14

right

Question 15

What is a tricuspic valve?

Answer 15

a valve with 3 leaflets

Question 16

Where are pocket valves located?

Answer 16

the veins to ensure that blood flows towards the heart, not away

Question 17

What is cardiac output?

Answer 17

the volume of blood pumped by one ventricle of the heart in one minute

Question 18

What is the equation for cardiac output?

Answer 18

heart rate x stroke volume

Question 19

What is stroke volume?

Answer 19

the volume of blood pumped out per beat

Question 20

What are the units for cardiac output?

Answer 20

dm³min^-1

Question 21

What are arterioles?

Answer 21

smaller arteries that control blood flow to capillaries

Question 22

What are capillaries?

Answer 22

tiny blood vessels that link arterioles to veins

Question 23

What is the layered structure of arteries, arterioles and veins?

Answer 23

from outside to inwards:

tough outer layer

muscle layer

elastic layer

lining layer

lumen

Question 24

What are the differences between the structure of a vein and artery?

Answer 24

veins - larger lumen

arteries - thicker elastic layer

arteries - thicker muscle layer

Question 25

What is the structure of a capillary?

Answer 25

consists of lining layer and lumen

highly branched

narrow lumen

spaces between lining cells

Question 26

How does having a thick muscle layer help arteries?

Answer 26

it means that smaller arteries can be constricted and dilated to control the volume of blood passing through them

Question 27

How does having a thick elastic layer help arteries?

Answer 27

the elastic wall is stretched at each systole and springs back at each diastole

this stretching and recoil action helps maintain high pressure and smooth pressure surges from the heart

Question 28

How does having thick walls help arteries?

Answer 28

prevents it bursting under pressure

Question 29

Why do arteries have no valves?

Answer 29

the blood is under constant pressure from the heart, so blood doesn’t flow backwards anyway

Question 30

What is the structure of an arteriole?

Answer 30

muscle layer thicker than arteries

elastic layer thinner than arteries

Question 31

How does having a thick muscle layer help arterioles?

Answer 31

allows lumen to become thinner

this restricts flow of blood and controls the movement of blood into capillaries

Question 32

Why is the elastic layer thinner in arterioles than arteries?

Answer 32

the blood pressure is lower

Question 33

Why is the muscle layer thin in veins?

Answer 33

as they carry blood away from tissues, they can’t control flow of blood with constriction so extra muscle not needed

Question 34

Why is the elastic layer thin in veins?

Answer 34

the low blood pressure won’t cause them to burst and pressure is too low to cause a recoil action

Question 35

Why are vein walls overall very thin?

Answer 35

there is no need for a thick wall due to low blood pressure

allows them to be flattened easily to aid with flow of blood

Question 36

Why are valves present in veins?

Answer 36

to ensure blood doesn’t flow backwards, which is a risk at this low pressure

Question 37

Why do capillary walls mostly consist of lining?

Answer 37

allows them to be extremely thin, increasing efficiency of diffusion

Question 38

Why are capillaries highly branched?

Answer 38

creates a large surface area for exchange

Question 39

Why is the lumen of capillaries narrow?

Answer 39

means that red blood cells are squeezed flat against the side of a capillary, bringing them closer to respiring tissue and increasing efficiency of diffusion

Question 40

What does tissue fluid supply tissues with?

Answer 40

glucose, amino acids, fatty acids, dissolved ions, dissolved oxygen