control of heart rate

Question 1

what are safety precautions that should be taken when dissecting a heart

Answer 1

-wash hands
-use a sharp scalpel/ scissors
-disinfect bench/ equipment
-cover any cuts
-cut away from self
-safe disposal

Question 2

caffeine affects the autonomic system, why does it lead to a high heart rate

Answer 2

-it leads to more impulses being sent to along the sympathetic nervous system; to SAN increasing heart rate (from cardiovascular centre)

Question 3

exercise causes an increase in heart rate, describe the role of receptors and of the nervous system in this process

Answer 3

-chemoreceptors detect a rise in CO2/ acidity OR baro/pressure receptors detect a rise in blood pressure.
-send impulses to the cardiac centre/ medulla oblongata
-more impulses to the SAN
-by sympathetic or parasympathetic (action potentials)

Question 4

explain how damage to the myelin sheath can cause muscular paralysis

Answer 4

-ref to saltatory conduction. OR. depolarisation occurs over the whole length of the axon
-nerve impulse slowed/ stopped
-ref to neuromuscular junction/ sarcolemma

Question 5

a patient has autonomic system problems, explain why this may cause heart rate irregularities

Answer 5

-slower/ fewer impulses along sympathetic/ parasympathetic pathway
-impulses from cardiac centre/ medulla oblongata to SAN