Lecture 4 - The Autonomic Nervous System and the CVS Flashcards
what comprises the ans?
two neurones - pre and post ganglion
one cell body in cns
one cell body in pns
where does the sympathetic nervous system come from?
thoraco lumbar outflow
describe the thoraco lumbar outflow
nerve fibres have cell bodies in all 12 thoracic sections and the first 2 lumbar sections
may synapse at same level as origin, different level to origin or not in paravertebral chain
describe the neurones in the sympathetic nervous system
preganglionic are cholinergic
postganglionic express nicotinic receptor
postganglionic are cholinergic
where does the parasympathetic nervous system come from?
craniosacral outflow
describe the neurones in the parasympathetic nervous system
preganglionic are cholinergic
postganglionic express nicotinic receptors
postganglionic are cholinergic
how does the sympathetic nervous system affect arterioles?
vasoconstriction via alpha 1 adrenoceptors
what is vasomotor tone?
constant activity of the sns
how is sympathetic outflow to blood vessels controlled?
from the brainstem via vasomotor centres in the medulla oblongata
what is the balance between pns and sns on the heart at rest?
pns dominates sns
What is the sympathetic effect on the heart and its receptor?
Increase rate/force of contraction.
B1 receptor.
What is the sympathetic effect on the airway and its receptor?
Relax.
B2 receptor.
What is the sympathetic effect on the pupil and its receptor?
Dilation.
a1 receptor.
What is the sympathetic effect on the sweat glands and its receptor?
Localised secretion.
a1 receptor.
General secretion.
M3 receptor.
What is the parasympathetic effect on the heart and its receptor?
Decrease rate.
M2 receptor.
