Autonomic Physiology Flashcards
Where is information from afferent/sensory neurons processed for the autonomic reflex arc?
In brain, hypothalamus
How is sensory info relayed form periphery to the CNS?
Afferent neuron
where is neuronal circuit for many motor reflexes found?
Within the spinal cord
What nerve and what kind usually, relays signal to the skeletal muscle?
Efferent neuron (usually an alpha motor neuron)
In autonomic all reflexes, processing of the inputs occurs where?
In the CNS , especially the hypothalamus
What does takes the place of the alpha-motor neuron when stimulating viscera?
ANS
For the ANS, where does each neuron begin and terminate?
Presynaptic: begins in cell body in CNS, ends in peripheral ganglion
Postsynaptic: begins in ganglion; terminates in an end organ
WHat are varicosities?
In the 2nd synapse of ANS
Contains allot he components of the presynaptic terminal and works the same as an NMJ presynaptic terminal
The postsynaptic terminal of the ANS is special how compared to the NMJ?
Ligand gated receptors are more spread out compared to the NMJ
Scattered in order to catch all of neurotransmitter
In Parasympathetic:
What is the neurotransmitter released at synapse 1?
Acetylcholine
In sympathetics:
What is the neurotransmitter released at synapse 1?
Acetylcholine
In Parasympathetic:
What is the receptor on post-ganglionic cell?
Nicotinic cholinergic Rs.
In sympathetics:
What is the receptor on post-ganglionic cell?
Nicotinic cholinergic rs.
In Parasympathetic:
What is the neurotransmitter released on target tissue?
Acetylcholine
In Sympathetics:
What is the neurotransmitter released on target tissue?
Norepinephrine
In Parasympathetics:
What is the receptor on target tissue cells?
Muscarinic cholinergic r.
In Sympathetics:
What is the receptor on target tissue cells?
Adrenergic Rs. (Alpha and beta)
What are the characteristics of Muscarinic Rs.?
ACh binds and activates
Muscarinic can also activate
Part of metabotropic (serpentine) super family of receptors
Uses a second messenger system
5 subtypes
What will M1R do?
Increase secretions of salivary gland and acid secreting cells of stomach
What will M3R do?
Contract Smooth muscle cells
Stimulate exocrine glands, sweat glands
What are the characteristics of adrenergic receptors?
Member of serpentine superfamily, uses second messenger system, 2 major classes (alpha adn beta)
What G system are each adrenergic receptor assoc. with?
Alpha 1: Gq Alpha 2: Gi Beta 1: Gs Beta 2: Gs Beta 3: Gs
QISSS (kiss)
What is the rule of thumb for adrenergic receptors?
Alpha adrenergic = constrict
Beta adrenergic = relax
What will alpha 1 do to blood vessels?
Contract and increase BP
What will alpha 2 do to blood vessels?
Dilate
What does beta-2 do to eye muscle?
Relaxes ciliary muscle
Thus flattening lens, allowing you to see at a distance
Where is beta -3 located?
White and brown adipose tissue
Allows for lipolysis
What receptor will dilate (symph.) the iris of the eye?
Constrict? (Paras.)
Alpha 1
M3R
What receptor will relax the ciliary muscle of the eye ( symph. ) ?
Contract it (paras.)?
B2
M3R
What receptor reduces secretion to salivary glands (symph.)?
What receptor increases watery secretion (paras.)?
Beta 1
M1R
What will increase secretion of lacrimal glands ( paras.) ?
M3R
What will increase the rate of Heart via the SA node (symph.)?
Decrease rate (paras.)?
Beta -1
M2R
What increases the strength of contraction via the heart muscle (symp.)?
Beta-1
What constricts blood vessels (sympathetics)?
What dilates (sympathetics)?
Alpha 1 (constrict to places we dont need blood for a flight or fight response, like GI tract)
Alpha 2 (dilate to places we want blood)
What dilates bronchi (sympathetics)?
What constricts bronchi (paras.)?
Beta-2
M3R
What decreases GI secretion (symph)?
What increases GI secretion(paras.)?
Alpha 1 (also constricts blood vessels, makes sense)
M1R
What increases GI Sphincter (sympathetics)?
What decreases (paras.)?
Alpha 2
M3R
What increases sweat glands (sympathetics)?
M3R
What increases glycogenolysis/gluconeogenesis of the liver (Sympathetics)?
Alpha-1, beta-2
What increases lipolysis of adipose tissue(sympathetics)?
Alpha 1, beta 1, beta 3
What contains chromaffin cells and what do they do?
Adrenal medulla
Make and release epinephrine as part of sympathetic response
Adrenal medulla in Sympathetic response:
Where will pre-ganglionic axons synapse?
Leave spinal cord and pass thru ganglion without synapsing
Instead synapse on chromaffin cells of adrenal medulla
Adrenal medulla in Sympathetic response:
What do Preganglionic Axons release and where will it bind? What does this activate?
Acetylcholine
Bind nicotinic receptors on adrenal cells
Activates muscarinic receptors that will release epinephrine into blood
What is the “rest and digest” response?
Parasympathetics
Have plenty of O2 Heart beats slow BP is low Digesting food Fuel is from GI tract
What is the “Fight or Flight” response?
Sympathetic
Need lots of O2 to go to muscles (not GI anymore)
Heart pumps fast and hard
Not digesting (need blood elsewhere)
Need fuel (not from GI so from lipolysis and gluconeogenesis and glycogenolysis)
What are the reactions seen in a Sympathetic response?
Pupil dilates
Lens flattens (ciliary m. Relaxed)
Heart rate increased
Strength of contraction in heart increased
Blood vessels of Ms. dilated
Blood vessels of Gi tract constricted
Blood vessels of skin constricted
Bronchial smooth muscle dilate
Lung secretions decreased
Gi motility decreased
GI secretions decreased
Liver has increased glycogenolysis and gluconeogenesis
Adipose tissue has increased lipolysis
What will not change during a sympathetic response?
Blood supply to lungs, heart and brain
What will always be on when parasympathetics are on?
Sympathetics
one is never not on, it is all a balancing act and we need both to work properly
Parasympathetic:
many subunits does a nicotinic acetylcholine receptor have? (1st synapse)
What are they coded for by?
What kind of receptor is it?
5 subunits
Each coded for a by a different gene
Ligand gated sodium channel —> causes a fast Epps in the post synaptic cell
Parasympathetic:
How are the pre and post ganglionic axons characterized?
Pre = long axon
Post = short axon
Does each neuron have many or just one varicosity?
Several varicosities for each neuron
Where is M1 receptor found ?
What type is it?
Salivary gland and in stomach
Gq
Where are M2 receptors found? What is it connected to?
What does it cause
Cardiac tissue
Gi
Decrease in camp, eventual increase in K conductance
where is M3 found? What is it connected o? What does it do?
Many different tissues, including glandular tissue and binding of ACh
Gq
Increase in IP3, DAG, eventual increase in intracellular Ca levels
Where are M4 receptors found? What are they connected to?
What do they do ?
As autoreceptors on neurons (controlling release of ACh)
Gi
Inhibit adenylate Cyclase
Describe pre and post ganglionic fibers int he sympathetic system (long v. Short)?
Pre: short
Post: long
Sympathetics:
What types of potentials can be produced?
Fast epsp = ACh
Slow ipsp = dopamine, interneurons
Slow epsp = ACh at m1
Late, slow epsp = GnRH
Sympathetics:
What happens when ACh binds to the Nicotinic receptor on chromaffin cells?
Secrete
Epinephrine, dopamine, and norepinephrine
All three bc they all come from tyrosine
Why do we have multiple receptor types?
By having multiple receptors, we can use the same neurotransmitter to accomplish different things
What does an increase in potassium conductance mean?
Means more potassium is moving
Potassium tends to leave cell if given chance
So an increase in potassium conductance = more potassium is leaving = cell becomes more negative = hyperpolarized = cell less excitable
How does the radial muscle of the iris relax?
Only innervated by sympathetics!
So it relaxes and allows sphincter muscle to take over when the activity in the sympathetic neuron decreases
(Good example of balancing act b/w paras. And sympath.)
Cell body of post ganglion axon is found in a ganglion located on target organ.
What receptor type is found on the cell body of this neuron within the ganglion?
On target organ = paras.
In ganglion: nicotinic cholinergic
In target tissue = muscarinic cholinergic
Activation of which receptor type will cause an increase in the inotropic state of the heart?
Inotropic state: contractility of heart
(Increased contractility —> increased stroke vol.)
Cardiac myocytes = beta adrenergic (mostly beta-1)
What neurotransmitter receptor is found on the chromaffin cells of the adrenal gland? What binds here?
Nicotinic cholinergic
ACh
Activation of which receptor type will most likely directly causes relaxation of vascular smooth muscle?
Beta-adrenergic
*remember rule of thumb, beta relax, alpha constrict