Responses to Challenge

Question 1

Describe capillaries at rest

Answer 1

Mostly closed, small amounts of blood going through them

Question 2

What happens to the capillaries during exercise?

Answer 2

Metabolites build up causing vasodilation and more capillaries are therefore required

Question 3

What is the equation for Total Peripheral Resistance?

Answer 3

R= 8Ln/pi x R4
R= resistance to flow
L= length of vessel
N= viscosity
R= radius of vessel

Question 4

Why does cardiac output increase?

Answer 4

Caused by increased stroke volume, increased heart rate (Starling mechanism- increased flow to the heart, puts stretch on muscle cells, lined up for maximal efficiency, and can increase blood flow)

Question 5

What is Starling’s Law?

Answer 5

The stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (the end diastolic volume) when all other factors remain constant.

Question 6

How do you calculate maximum heart rate?

Answer 6

220-age

Question 7

Signs of haemorrhage

Answer 7

Pallor- due to peripheral vasoconstrictions
Cold skin- due to peripheral vasoconstrictions
Rapid Pulse- circulating adrenaline and noradrenaline
Sweating- counter productive,
Confusion
Increased Respiratory rate