TEST 3 - ANS/ADRENAL MEDULLA Flashcards
Innervates tissues/organs NOT usually under voluntary control
Autonomic nervous system
What tissues/organs are innervated by the ANS?
Cardiac muscle Electrical fibers of heart Smooth muscle of blood vessels, ducts, urinary bladder, uterus, etc. Glands Visceral (GI) muscle
Where do the nerve cell bodies for somatic motor pathways start?
Anterior horn of the gray matter
From the spinal cord to the muscle, how many neurons in sequence in a somatic motor pathway?
ONE
How many neurons in sequence for an autonomic pathway? What are they called?
2 neurons
Preganglionic neuron
Postganglionic neuron
Where are the nerve cell bodies located for autonomic pathways?
Lateral horns of the gray matter (T1-L2; S2-S4)
Preganglionic neuron originates in the ______ horn of the gray matter and exits through the ______ horn of the gray matter.
LATERAL HORN
EXITS ANTERIOR HORN
Preganglionic neuron synapses with postganglionic neuron here
Autonomic ganglia/ganglion
PRE/POST ganglionic neuron synapses with target tissue
Postganglionic
2 divisions of the ANS
Sympathetic NS
Parasympathetic NS
Another name for sympathetic NS
Thoracolumbar division
Preganglionic neurons for this division of the ANS originate in the lateral horns of the gray matter at spinal segments T1-L2
Sympathetic NS
Another name for parasympathetic NS
Craniosacral Division
Where do preganglionic neurons originate for the PNS ?
In the brain stem (CN III, VII, IX, and X)
Lateral horns of the gray matter at spinal segments S2-S4
ALL preganglionic fibers in the ANS are MYELINATED. TRUE/FALSE?
TRUE
All preganglionic myelinated fibers are type ___ fibers
Type B
ALL postganglionic fibers of the ANS are MYELINATED TYPE B FIBERS.
TRUE/FALSE?
FALSE
Postganglionic fibers are UNMYELINATED TYPE C fibers
These lay on either side of the SC and anteriorly to the SC; associated with SNS.
Sympathetic chain ganglia on either side of the SC
Collateral ganglia, lays anterior to SC
In the upper thoracic region preganglionic neurons of the SNS synapse with postganglionic neurons where?
Sympathetic chain ganglia
After ~ T ____, preganglionic neurons of the SNS pass through the sympathetic chain ganglia and synapse with postganglionic neurons in the collateral ganglia
~T5
Preganglionic fibers of the SNS tend to be SHORT/LONG fibers, postganglionic fibers tend to be SHORT/LONG.
Pre = SHORT Post = LONG
Ganglia specific for PNS
TERMINAL ganglia
Why are PNS terminal ganglia called ‘terminal’?
Lies right next to tissue being innervated, sometimes even in the wall of the tissue
In the PNS, preganglionic fibers tend to be LONG, and postganglionic fibers tend to be SHORT.
TRUE/FALSE
TRUE
MOST organs are innervated by PNS, but only select few are innervated by SNS. TRUE/FALSE
FALSE
ALL organs are innervated by BOTH the PNS/SNS
Usually either the PNS or SNS is predominating, but this does not mean the other is absent. TRUE/FALSE
TRUE
In a TYPICAL SYMPATHETIC pathway, preganglionic myelinated fiber exits SC (T1-L2), synapses with postganglionic fiber at sympathetic autonomic ganglia and (NT) _____________ is released and binds to ____________ receptors on the postganglionic _________.
Ach is released
Binds with Nicotinic type II receptors
On the postganglionic Dendrite
In a TYPICAL sympathetic pathway, after postganglionic neuron synapses with target tissue, what NT is released and what type of receptors does is bind to to elicit physiologic response?
NE released
Binds with adrenergic receptors (alpha/beta)
The TYPICAL sympathetic pathway is described as a sympathetic ____________ response, the ATYPICAL sympathetic pathway is described as a __________ pathway
Typical = adrenergic response
Atypical = CHOLINERGIC response
What are the 2 sympathetic cholinergic responses that follow an atypical sympathetic pathway?
Thermoregulatory sweat glands
Pyeloerector muscles (goosebumps)
In an ATYPICAL sympathetic cholinergic pathway, sequence is the same, except, the postganglionic neuron synapses with target tissue and releases (Nt) ___________ and the target cell receptors are _________.
Releases ACH
Target cell receptors are MUSCARINIC
ALL parasympathetic pathways follow the same sequence, NO deviations. TRUE/FALSE
TRUE
At ALL preganglionic/postganglionic synapses, the NT is ________ and the receptors are )_________.
Nt ACH
Receptors: Nicotinic type II
What is a good example of an autonomic reflex; sensory input, autonomic output.
Baroreceptor Reflex
Where are the baroreceptors located?
Internal carotids and aortic arch
CN _____ is associated with internal carotid baroreceptors.
CN IX
CN X is associated with baroreceptors located where?
Aortic arch
What excites baroreceptors?
Increased BP
Increased BP increases tx of impulses through CN IX and X, these two pathways join to form _________, and terminate in ____________ in the medulla.
Tractus solitarius
Nucleus solitarius
When nucleus solitarius is excited, its excites ___________ receptors.
Central alpha II receptors
The end result of the baroreceptor reflex allows the PNS/SNS to predominate.
PNS
What is an example of an alpha II drug we might give that would slow the HR?
Precedex
Decreased HR, decreased strength of contraction, decreased stroke volume, blood vessel dilation, decreased preload all lead to decreased _______ in the PNS dominance from the baroreceptor reflex.
Decreased BP
When BP is low, there is less excitation of baroreceptors, less impulses through CN IX/X, nucleus solitarius and central alpha II are NOT excited, and this allows for PNS to predominate. TRUE/FALSE.
FALSE
Allows for SNS to predominate!!
PNS/SNS primarily innervated the SA node.
PNS
Decreased strength of contraction in the baroreceptor reflex is primarily due to what?
Lack of sympathetic innervation.
SA node, AV node, and ventricular contractile fibers are all innervated SYMPATHETICALLY.
TRUE/FALSE
TRUE.
We are unable to control/impact autonomic outflow. TRUE/FALSE.
FALSE
We can impact autonomic outflow with higher brain centers, cerebrum, and limbic system.
What are some examples of higher brain centers/ limbic system affecting autonomic outflow?
Nervous for test = increased HR/RR
Meditation = decrease HR
Pass out from IV stick
Sympathetic innervation of the pupil = __________
Pupil dilation
Sympathetic innervation of bronchiolar smooth muscle = ____________ for increased gas exchange
Dilation
CN ______ causesed _________ innervation of the pupil = pupillary constriction.
CN III; Parasympathetic
CN VII innervates what 3 things?
Lacrimal glands (tears) Nasal mucosa Salivary glands
CN ____ innervates the parotid gland
IX
Major parasympathetic nerve; “to wander”.
Vagus; CN X
Parasympathetic innervation of bronchiolar smooth muscle = __________ constriction
Mild
__________ smooth muscle has a lot of sympathetic innervation and very little, if any, parasympathetic innervation.
Vascular
Vasodilation is due to parasympathetic innervation directly. TRUE/FALSE.
FALSE
Vasodilation is due to LACK of sympathetic innervation
Blood vessels, except for maybe __________ vessels, do not have parasympathetic innervation
Coronary
A specific sympathetic pathway, PREganglionic neuron passes through the chain ganglia, collateral (celiac) ganglia and preganglionic neuron synapses directly on the __________
Adrenal medulla
At the preganglionic synapse on the adrenal medulla, NT released is _________ and the target receptor is ________.
ACh
Nicotinic type II
The adrenal medulla acts like a postganglionic neuron and released what 3 things?
NE
Epi
Dopamine
This is a most potent Nt released from the adrenal medulla and released in the greatest quantity, ____%.
Epi
80-85%
The adrenal medulla is one of only two places that the enzyme exists to convert NE to Epi. TRUE/FALSE
FALSE
Adrenal medulla is the ONLY place where enzyme is present to make Epi from NE
The adrenal medulla enhances over all __________ response
Sympathetic
If adrenalectomy performed, you will have NO Epi in your body. TRUE/FALSE
TRUE
How are the neurohormones produced by the adrenal medulla transported to other synapses of sympathetic postganglionic neurons?
In the blood
Catecholamine secreting tumor arising primarily from adrenal medulla tissue.
Pheochromocytoma
Most common manifestations of pheochromocytoma (5)
Htn (refractory to Tx) Headache Palpitations Sweating Nervousness
What is the treatment for pheochromocytoma?
Surgical resection
Surgical resection of pheochromocytoma is associated with what during anesthesia and surgical intervention?
Unpredictable and fluctuating hemodynamics
Pheochromocytoma can go undiagnosed and present for Sx for another disease process or emergency. TRUE/FALSE.
TRUE
Preoperative management for surgical resection of pheochromocytoma must begin _________ in advance
Weeks
May need what to determine cardiac involvement of pheochromocytoma
EKG
Echo
Medications given to optimize pt for surgical resection of pheochromocytoma
Alpha-adrenergic blockers
Beta-blockers
Common alpha-adrenergic blocker given to optimize pt for surgical resection of pheochromocytoma
Prazosin
Typical dosing period of alpha-adrenergic blocker (prazosin) is _________ weeks prior to Sx.
2-8 weeks
Never start the patient on _____________ prior to _____________ because can lead to hypertensive crisis and pulmonary edema.
Never start BB before Alpha blockers
Monitors for surgical resection of pheochromocytoma
Arterial line
Large bore IV’s
Not usually central line, PA cath, or TEE
Induction and intubation should be as smooth and non-stimulating as possible, what are some ways to do this?
Consider giving lidocaine, LTA kit.
Make sure very deep before intubation
How can we be ready for extreme fluctuations in blood pressure?
Have variety of vasoactive drugs available!! Uppers and downers.
Have IV fluids and blood readily available
Any manipulation of tumor can cause significant hemodynamic instability, so communication with ________ is key for success!!
Surgeon
What is the most significant portion of the case (surgical resection of pheochromocytoma)?
Manipulation of the tumor!!
After Sx resection of tumor, Postoperatively, pts can still have hemodynamic instability and are typically transferred to _______
ICU
After removal of pheochromocytoma, pts should have follow up for one year. TRUE/FALSE
FALSE
Should have LIFE LONG FOLLOW UP due to recurrence
Difference between NT and neurohormone
NT = NE released at postgang symp neuron into a synapse
NH = NE, Epi, dopamine released from Ad. Medulla bc acts like NT bc bind to same receptors but act like hormones as well bc released, travel throughout body in blood and then released at receptor
What type of receptors does dopamine bind to
D-1 and D-2 receptors
NE receptors and in order
Alpha-1 > Beta-1 > beta-2
Epi receptors in order
Beta-2 > Beta-1 = Alpha-1
Parasympathetic cholinergic NT and receptors
Ach:
Nicotinic-2, muscarinic receptors
Where are Nicotinic type I receptors found
Skeletal muscle
Alpha-1 and Beta receptors are ___________ coupled receptors
G-protein
In the inactivated state, the alpha subunit of the G-protein is connected to _______
GDP
When A-1 receptor becomes activated, alpha subunit breaks off and GDP is replaced by ______
GTP
During activation of alph-1 receptor, The alpha GTP complex binds with __________
Phospholipase C
Phospholipase C converts PIP2 into _________ and ______
Diacylglycerol
IP3
IP3 causes release of _______ from endoplasmic reticulum.
Calcium
The Ca released by IP3 and diacylglycerol increase ____________ which brings about the physiologic response.
Protein kinase C
Beta-1 and beta-2 receptors have the same mechanism. TRUE/FALSE.
TRUE
After beta receptor excited, alpha-GDP breaks off, GDP converted to GTP, and alpha-GTP complex binds with enzyme ___________
Adenylyl cyclase
Adenylyl cyclase converts ATP to cAMP, which increases _____________ to bring about physiologic response.
Protein Kinase A
Physiologic response depends on the target tissue. TRUE/FALSE
TRUE
Receptors that Usually lead to contraction of smooth muscle (particularly vascular)
Alpha-1
Receptors that Cause inhibition of target cell responses
Alpha-2 receptors
Receptors that cause inhibition of sympathetic outflow and allow parasympathetic domination
Central medullary alpha-2
Many on presynaptic membrane of sympathetic neurons; when activated, usually decrease NE release into synapse (from postganglionic fibers)
Peripheral alpha-2 receptors
Reason pts become tolerant of NE gtt
Over time will bind to peripheral alpha-2 receptors and decrease endogenous release of NE
Receptors that Play a role in metabolic fxns, heart, and JG cells of the kidneys (renin)
Beta-1
When JG cells in the kidneys are excited by NT, they release a substance called _______
Renin
Receptors that lead to relaxation of vascular and bronchiolar smooth muscle
Beta-2
Vascular smooth muscle does NOT have a lot of B-2 receptors. TRUE/FALSE
TRUE
Nicotinic type II (and type I) receptors are Ach gated _________ channels
Sodium
Most muscarinic receptors use same mechanism as ________ receptors
Alpha-1
The exception to muscarinic receptors acting like alpha-1 receptors, is where in the body?
Sinoatrial node of the heart
In the SA node of the heart, the alpha-GTP complex directly opens ________ channels in the SA node, which _____________ the SA node and decreased HR.
Directly opens POTASSIUM channels
HYPERPOLARIZES/INHIBITS the SA node
When K moves out of the cell, what causes the decreased HR?
RMP moves farther from TP, takes larger stimulus to get to TP, longer upstroke, more time between AP
Sympathetic stimulation of the SA node makes SA node more permeable to __________ which leads to hypopolarization of the cell and increased HR
Sodium
Most, but not all, target tissues/organs have both sympathetic and parasympathetic innervation. TRUE/FALSE
TRUE
BOTH sympathetic and parasympathetic excites some tissues/organs and inhibits others. TRUE/FALSE
TRUE
Most sympathetic target tissue/organs have alpha receptors and some beta, but alpha predominates. TRUE/FALSE
FALSE
BOTH alpha and beta receptors present on most tissues, but one or the other predominates
Responses in target tissues/organs depend on number and types of ________ in the organs.
Receptors