Function of the CVS

Question 1

What type of system is the CVS?

Answer 1

Bulk flow

Question 2

What 4 things is the CVS responsible for getting around the body?

Answer 2

• O2 and CO2
• Nutrients
• Metabolites
• Hormones

Question 3

What homeostatic aspect is regulated by the CVS?

Answer 3

Heat

Question 4

In what ways is the CVS flexible?

Answer 4

• Pump output can vary
• Vessels can redirect blood
• Vessels can store blood

Question 5

Describe the structure of the largest vessels of the CVS?

Answer 5

• Exist in series like an electrical circuit

- Output is equal

Question 6

How do vascular beds exist with reference to eachother?

Answer 6

In a parallel circuit

Question 7

What can occur to allow some beds to get more blood than others?

Answer 7

Regional redirection (vaso dilation/constriction in some vessels)

Question 8

Why are the hypothalamas and anterior pituitary gland in series and not parallel?

Answer 8

• Blood travels through the hypothalamus first

- Picks up hormone secretions that work directly on the pituitary

Question 9

What is the hierarchal order of organs by their O2

used?

Answer 9

Abdominal Organs
30%

Skeletal Muscles
20%

Brain
18%

Other
14%

Heart
10%

Kidney
6%

Skin
2%

Question 10

What is the hierarchal order of organs by their cardiac output used?

Answer 10

Abdominal Organs
24%

Skeletal Muscles
20%

Brain
13%

Other
10%

Heart
4%

Kidney
20%

Skin
9%

Question 11

What is the equation for pressure difference?

Answer 11

Pressure difference = mean arterial pressure - central venous pressure

Question 12

What happens to flow when pressure increases?

Answer 12

Flow increases

Question 13

What is the equation for flow?

Answer 13

Flow = change in pressure/resistance

Question 14

What effect does radius of vessel have on the resistance?

Answer 14

Radius^4 so has a huge effect

Question 15

What do arterioles act as by controlling resistance through radius?

Answer 15

Taps to each organ vascular bed

Question 16

Describe the properties of the aorta

Answer 16

• Large elastic wall

- Wide lumen

Question 17

How does the elasticity of the aorta aid in pumping blood?

Answer 17

• Gains elastic energy when stretches in response to systole
• Elastic walls can recontract to increase pressure and therefore flow

Question 18

Describe the properties of the arteries

Answer 18

• Muscular
• Wide lumen
• Low resistance

Question 19

What is the name given to the type of vessels that arterioles are?

Answer 19

• Resistance vessels

Question 20

What are the properties of arterioles?

Answer 20

• Narrow lumen
• Thick contractile wall
• Can control resistance and therefore flow

Question 21

What is the function of capillaries?

Answer 21

Exchange vessels

Question 22

What are the properties of capillaries?

Answer 22

• Narrow lumen

- Thin wall

Question 23

What is the name given to the type of vessels that venules and veins are?

Answer 23

• Capacitance vessels

Question 24

Describe the properties of veins and venules

Answer 24

• Wide lumen

- Low resistance

Question 25

What is the function of the interatrial septum?

Answer 25

Seperates left and right atrium

Question 26

What type of valves are the aortic and pulmonary valves?

Answer 26

Semi lunar

Question 27

What is the mitral valve?

Answer 27

• Also known as bicuspid as it has two cusps

- Left AV valve

Question 28

What is the tricuspid valve?

Answer 28

• Right AV valve

Question 29

What are the chordae tendinae?

Answer 29

Connective tissue fibres that connect the AV valves with the papillary muscle

Question 30

What is the function of the chordae tendinae and the papillary muscle?

Answer 30

• Stop the AV valve from inverting

- Is passive so allows the valve to shut but not go too far