Overview of the Function of the CV system

Question 1

What are the functions of the CV system?

Answer 1

Bulk flow system:

• O2 and CO2
• Nutrients
• Metabolites
• Hormones
• Heat

Question 2

Why is the CV system regarded as being flexible?

Answer 2

• It can vary pump output
• The vessels can redirect blood
• The vessels can store blood

Question 3

Why must output be from the right and left side of the heart be equal?

Answer 3

They are in series

Question 4

What is the importance of the right and left sides of the heart being in series?

Answer 4

If the weren’t then output would not be equal and there would be an accumulation of blood

Question 5

How are most vascular beds organised?

Answer 5

In parallel

Question 6

What does vascular beds in parallel allow?

Answer 6

• All tissues get oxygenated blood

- Allows regional redirection of blood

Question 7

What are 2 examples of vascular beds that lie in series?

Answer 7

• Hypothalamus and pituitary gland

- Gut and liver

Question 8

What is usually the relationship between oxygen consumption and cardiac output at rest/

Answer 8

The usually correlate so percentages are very close

Question 9

Why does skin have a high cardiac output?

Answer 9

It is involved in thermoregulation

Question 10

What is the pressure difference equal to?

Answer 10

Mean arterial pressure- central venous pressure

Question 11

What is flow equal to?

Answer 11

Pressure difference divided by the resistance

Question 12

What is resistance controlled by?

Answer 12

Radius of vessels

Question 13

What do the arterioles do?

Answer 13

They act as taps as the control the resistance and flow to each vascular bed.

Question 14

What is the order of the vessels that blood flows through upon leaving the heart?

Answer 14

• Arteries
• Arterioles
• Capillaries
• Venules
• Veins

Question 15

What is an example of an elastic artery?

Answer 15

Aorta

Question 16

What are the characteristics of elastic arteries?

Answer 16

• Wide lumen
• Elastic wall
• Damp pressure variations

Question 17

What are the characteristics of muscular arteries?

Answer 17

• Wide lumen
• Strong non-elastic wall
• Low resistant conduit

Question 18

Which vessels are referred to as the resistance vessels?

Answer 18

Arterioles

Question 19

What are the characteristics of the resistance vessels?

Answer 19

• Narrow lumen
• Thick contractile wall
• Control resistance and therefore flow
• Allow regional redirection of blood

Question 20

What vessels are known as the exchange vessels?

Answer 20

Capillaries

Question 21

What are the characteristics of the exchange vessels?

Answer 21

• Narrow lumen

- Thin wall

Question 22

What vessels are known as the capacitance vessels?

Answer 22

• Venules

- Veins

Question 23

What are the characteristics of the capacitance vessels?

Answer 23

• Wide lumen
• Distensible wall
• Low resistance conduit and reservoir
• Allows fractional distribution of blood between veins and rest of circulation

Question 24

What enhances the diffusion ability of capillaries?

Answer 24

Their large surface area to volume ratio

Question 25

Septum

Answer 25

Separates the left and right sides of the heart

Question 26

Myocardium

Answer 26

Heart muscle

Question 27

Atrium

Answer 27

Receiving chamber

Question 28

Ventricle

Answer 28

Pumping chamber

Question 29

Aorta

Answer 29

Vessel leaving left ventricle

Question 30

Vena cava

Answer 30

Vessel arriving at right atrium

Question 31

Pulmonary trunk

Answer 31

Vessel leaving right ventricle

Question 32

Pulmonary veins

Answer 32

Vessel arriving at left atrium

Question 33

Aortic valve

Answer 33

Prevents blood flowing back into left ventricle

Question 34

Pulmonary valve

Answer 34

Prevents blood flow back into right ventricle

Question 35

Mitral valve

Answer 35

Separates left atrium and ventricle

Question 36

Tricuspid valve

Answer 36

Separates right atrium and ventricle

Question 37

Chordae tendinae

Answer 37

Attach to capillary muscle

Question 38

Papillary muscle

Answer 38

On, contraction they open the mitral and tricuspid valves and stops them inverting and turning inside out