Q3: Pressure in blood vessels and heart rate

Question 1

Different types of blood vessels

4

Answer 1

veins
capillaries
arteries
arterioles

Question 2

Arteries

Answer 2

Carry blood away from the heart and into arterioles

Question 3

Arterioles

Answer 3

Smaller arteries that control blood flow from arteries to capillaries

Question 4

Capillaries

Answer 4

Tiny vessels that link arterioles to veins

Question 5

Veins

Answer 5

Carry blood from capillaries back to the heart

Question 6

Five components of same basic layered structure in arteries, arterioles and veins

Answer 6

• tough fibrous outer layer
• muscle layer
• elastic layer
• thin inner lining (endothelium)
• lumen

Question 7

Tough fibrous outer layer

Answer 7

resists pressure changes from both within and outside

Question 8

Muscle layer

Answer 8

can contract and so control the flow of blood

Question 9

Elastic layer

Answer 9

Helps to maintain blood pressure by stretching and springing back (recoiling)

Question 10

Thin inner lining (endothelium)

Answer 10

Is smooth to reduce friction and thin to allow diffusion

Question 11

Lumen

Answer 11

Not a layer but the central cavity of the blood vessel through which the blood flows

Question 12

Pressure in arteries?

Answer 12

high pressure

Question 13

Why is the elastic layer in arteries relatively thick compared to veins?

Answer 13

important that high blood pressure is maintained so it can reach the extremities of the body,
elastic wall stretches and recoils to maintain high pressure and smooth pressure surges creating by the beating of the heart

Question 14

Thickness of the overall wall of the artery?

Answer 14

over thick

to resist bursting under high pressure

Question 15

Why are there no valves in arteries?

Answer 15

blood tends not to flow backwards due to constant high pressure

Question 16

Arterioles vs arteries pressure of blood

Answer 16

arterioles carry blood under lower pressure

Question 17

Muscle layer in arterioles compared to arteries?

Answer 17

relatively thicker in arterioles which allows constriction of the lumen of the arteriole, restricts blood flow and so controls its movement into capillaries

Question 18

Why is the elastic layer relatively thinner in arterioles compared to arteries?

Answer 18

because the blood pressure is lower in arterioles

Question 19

Veins blood pressure

where do they transport blood from and to?

Answer 19

low pressure

from capillaries in tissues to the heart.

Question 20

Why is the elastic layer in veins relatively thin?

Answer 20

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

Question 21

Why do veins have valves?

Answer 21

pressure is low, so they ensure backflow doesn’t occur

Question 22

Pocket valves

Answer 22

occur throughout the venous system

Question 23

Semi-lunar valves

Answer 23

in the aorta and pulmonary artery, prevent backflow of blood into the ventricles when the pressure in these vessels exceeds that in the ventricles

Question 24

Atrioventricular valves

Answer 24

between the atrium and ventricle on both sides, prevents backflow of blood when ventricular pressure exceeds atrial pressure

Question 25

Heart rate

Answer 25

the rate at which the heart beats

Question 26

Cardiac output

Answer 26

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

Question 27

Stroke volume

Answer 27

volume of blood pumped out at each beat

Question 28

Cardiac output equation

Answer 28

CO = HR x SV