Autonomic Nervous System Physiology Flashcards
What is the universal neurotransmitter for preganglionic neurons in the ANS?
Acetylcholine
Which has a higher preganglionic to postganglionic ratio, parasympathetic or sympathetic?
The sympathetic has a higher ratio (10:1) than the parasympathetic (3:1)
T or F?
The parasymphatethic has ganglia located near the spinal cord
False
The sympathetic has ganglia located near the spinal cord.
The parasymphthetic has ganglia located near the target organs.
T or F?
The postganglionic parasympathetic neurons release acetylcholine and the postganglionic sympathetic neurons release epinephrine and norepinephrine.
True
Sorry if these are too simple, I just wanted to do a quick refresher for myself.
What makes the adrenal medulla special in regards to the sympathetic nervous system?
The postganglionic cells located here secrete epinephrine and norepinephrine into the blood stream to bind to adrenergic receptors. Thus, these act as hormones as opposed to neurotransmitters.
T or F?
The sympathetic nervous system primarily controls vasodilation and vasoconstriction
True.
Increased sympathetic leads to vasoconstriction as well as increased heart rate and force of contraction
Which 4 cranial nerves are part of the parasympathetic nervous system?
III (oculomotor), VII (facial), IX (glosspharyngeal), X (vagus)
Which has longer postganglionic axons, sympathetic or parasympathetic?
Sympathetic.
By which mechanism are neurotransmitters (Ach and Norepi) released from postganglionic neurons of the ANS?
Exocytosis
Where are nicotinic receptors primarily located?
They are primarily present in the cell bodies of postganglionic neurons of the autonomic ganglia
Where are the muscarinic receptors primarily located?
Muscarinic receptors are present on the effector cells of cardiac muscle, smooth muscle, and glands
T or F?
The nicotinic receptor is a ligand-gated, selective channel
False.
It’s a ligand-gated, non-selective channel that opens when Ach binds it and allows for Na and K to move across the membrane, leading to depolarization and excitation.
What kind of proteins are associated with muscarinic receptors in the cell membrane?
G proteins. They carry out a lot of different physiological functions within the cell.
T or F?
There are 2 types of muscarinic receptors
False.
There are 5 subtypes. That’s why there’s such variety in what can happen when Ach binds to a muscarinic receptor and activates the G protein.
How many different subtypes of adrenergic receptors are there?
T or F?
Norepinephrine (NE) activates all of the adrenergic receptors
There are 4 types (alpha 1, alpha 2, beta 1, beta 2)
False.
NE only activates alpha 1, alpha 2, and beta 1. Epinephrine activates all 4.
T or F?
Beta blockers (propanalol) are good treatment for hypertension and coronary artery disease
True.
Epinephrine or a more selective B2 blocker would also be good for people w/ asthma who are experiencing bronchoconstriction.
Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor: Alpha 1
Vasoconstriction in skin.
Agonist: Phenylephrine
Antagonist: Doxazosin
Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor:
Alpha 2
CV: Presynaptic inhibition of NE release, some vasoconstriction
Agonist: Clonidine
Antagonist: Trazodone
Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor:
Beta 1
CV: Increased heart rate
Agonist: Dobutamine
Antagonist: Atenolol
Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor:
Beta 2
CV: Increased heart rate. Vasodilation in skeletal muscle
Agonist: Albuterol
Antagonist: Butaxamine
In the baroreceptor reflex, what response is expected when you have low blood pressure?
A relative increase in sympathetic output. The opposite is also true.
What is the effect in the heart if there is increased Ach release (ie increased parasympathetic)
The heart will beat slower with less force.
Why is the hypothalamus so important in homeostasis?
It’s the head control ganglion.
It controls different responses/reflexes of the autonomic nervous system.
It also controls release of hormones via the pituitary gland (vasopressin release which helps to control blood pressure).
The hypothalamus coordinates the ANS and humoral responses.
What’s the effect of vasopressin?
It causes increased vasoconstriction as well as increased water retention in the kidneys in response to low blood pressure.
What do renin and angiotensin do in response to low blood pressure?
Renin activates angiotensin to angiotensin I which then goes on to become angiotensis II which constricts blood vessels, increases water retention in the kidneys, and activates neurons in subformical organs.
Controlled by the hypothalamus.
