Physiology of ANS Flashcards
Where are the inputs of the autonomic nervous system processed?
in the CNS, particularly the hypothalamus
What is the neurotransmitter used by both the sympathetic and parasympathetic nervous systems at the first synapse?
Ach
What type of receptors are on the post-ganglionic cells of the first synapse of both the sympathetic and parasympathetic nervous systems?
nicotinic
What type of receptor is used at the second synapse for the sympathetic nervous system?
adrenergic
What type of receptor is used at the second synapse for the parasympathetic nervous system?
muscarinic
What type of receptors are the adrenergic and muscarinic receptors?
serpentine super family of receptors
Where do the impulses exit from the CNS in the sympathetic response?
Thoracic and lumbar regions
Where do the impulses exit from the CNS in the parasympathetic response?
Cranial and sacral
Where is the location of the second synapse in the sympathetic response?
sympathetic chain
Where is the location of the second synapse in the parasympathetic response?
at the target organ
How do the lengths of the pre-ganglionic fiber differ between sympathetic and parasympathetic response (when referring to the 2nd synapse)?
Sympathetic - short
Parasympathetic - long
How do the lengths of the post-ganglionic fiber differ between sympathetic and parasympathetic response (when referring to the 2nd synapse)?
Sympathetic - long
Parasympathetic - short
What are the specific receptors for the parasympathetic response?
M1R, M2R, M3R
nobody cares about 4 or 5
What are the specific receptors for the sympathetic response?
Alpha-1, Alpha-2
Beta-1, Beta-2, Beta-3
What is the parasympathetic response when an M1R is activated?
increased salivation
increased GI secretion
What is the parasympathetic response when an M2R is activated?
K+ channels open = cell re-/hyperpolarization
HR slows
What is the parasympathetic response when an M3R is activated?
inceased smooth muscle ctx
- GI motility
- bronchi constriction
increased exocrine gland secretion
-lacrimal, sweat
ciliary M. relaxes = pupil constriction (round lens)
What is the sympathetic response when an alpha-1 receptor is activated?
blood vessel smooth muscle ctx = BP increases
increased gluconeogenesis, increased glycogenolysis
increased lipolysis
What is the sympathetic response when an alpha-2 receptor is activated?
GI sphincter constriction
pancreas increases glucagon, decreases insulin
increase in platelets = clotting
What is the sympathetic response when a beta-1 receptor is activated?
HR increases
cardiac muscle ctx strength increases
decreased salivation
increases lipolysis
What is the sympathetic response when a beta-2 receptor is activated?
bronchiole smooth muscle dilation
GI smooth muscle relaxation
increased glycogenolysis and gluconeogenesis
increased lipolysis
What is the sympathetic response when a beta-3 receptor is activated?
adipose tissue (white) = increased lipolysis adipose tissue (brown) = increased thermogenesis
What are chromaffin cells?
cells in the adrenal medulla that make and secrete epinephrine
How is the adrenal medulla involved in the sympathetic response?
some sympathetic axons synapse in the adrenal medulla as their 1st synapse (instead of the paravertebral ganglion)
Ach then binds to nicotinic receptors on chromaffin cells which release epinephrine
Name some key aspects of the “fight or flight” response.
- need lots of oxygen to get it to the muscles
- heart is pumping hard and fast
- limited digestion
- pupil dilates and lens flattens
- skeletal muscle, lung/heart/ brain blood vessels dilate
- GI and skin blood vessels constrict
