control of heart rate exam questions

Question 1

name valve A and chamber B

Answer 1

Valve A - atrioventricular
Chamber B - left ventricle

Question 1

Give two safety precautions that should be followed when dissecting a heart

Answer 1

cut away from self
use a sharp scalpel

Question 2

explain how valve A in figure 1 maintains a unidirectional flow of blood (2 marks)

Answer 2

M1: pressure in atrium is higher than in ventricle B causing valve to open
M2: pressure in left ventricle is higher than in atrium causing valve to close

Question 3

suggest how caffeine could account for the results in group 1 in figure 2 at 60 minutes (2 marks)

Answer 3

M1: more impulses along sympathetic pathway
M2: to SAN increasing heart rate