Nervous System

Question 1

Sympathetic nerves

Answer 1

Short pre-ganglionic fibre, long post ganglionic fibre
Preganglionic neurotransmitter: Ach
Postganglionic neurotransmitter: noradrenaline

Question 2

Cardiac accelerator nerves

Answer 2

Release noradrenaline, binds to B1 receptors = positive chronotropic and ionotropic effect
(Sympathetic) (adrenaline also acts on B1Rs)

Question 3

Parasympathetic influence on heart

Answer 3

Vagus nerves, release Ach, act on muscarinic receptors 
Reduces HR (-ve chronotropic)

Question 4

Mean arterial pressure

Answer 4

MAP = D + 1/3 (S-D)

Question 5

Carotid sinus nerve

Answer 5

Glossopharyngeal

Question 6

Aortic baroreceptor nerve

Answer 6

Aortic nerve -> vagus

Question 7

Increase in MAP

Answer 7

Stretches carotid sinus- stimulates baroreceptors = increased frequency of action potentials
Stimulates cardio inhibitory centre, inhibits cardioacceleratory centre

Question 8

Arterial chemoreceptor nerves

Answer 8

Carotid sinus- glossopharyngeal nerves

Question 9

Increase in carotid and aortic chemoreceptor discharge

Answer 9

Fall in PO2 (hypoxaemia)

Question 10

Circulating adrenaline acts on

Answer 10

A1 receptors and B2 receptors (vasodilatation)