Autonomic Nervous System Flashcards
(T/F?) Adrenergic Receptors can also bind Dopamine?
True
Define the ANS?
The ANS is the involuntary branch of the PNS that conducts impulses from brainstem or spinal cord to cardiac muscle, smooth muscle and glandular tissue.
Other names for the ANS
1) Visceral Nervous System
2) Involuntary Nervous System
3 Divisions of the ANS?
1) Sympathetic
2) Parasympathetic
3) Enteric (GI) Nervous system
The ANS regulates involuntary activities such as?
1) Visceral functions
2) Metabolic functions to maintain homeostasis
3) BP & HR
4) GI motility and secretion
5) Bladder emptying/filling
6) Sweating and temperature regulation
7) near/far vision and pupil size
8) secretions of certain endocrine glands
What role is the Enteric Nervous System responsible for within the ANS?
The processes of mixing, propulsion, and absorption of nutrients in the GI tract.
How does the ENS regulate digestive activity?
Via the mycenteric and the sub mucous plexi
(T/F?) Serotonin is also a neurotransmitter used by the ENS?
True
The ANS is regulated by which higher centers of the brain?
1) Hypothalamus - Acts as a signal relay and integration center
2) Medulla - Hemodynamic and ventilatory control
3) Pons - Hemodynamic and ventilatory control
Cholinergic Axon vs. Cholinergic Receptor?
1) Cholinergic Axon - A nerve fiber that secretes ACh
2) Cholinergic Receptor - A receptor that binds to ACh
Adrenergic Axon vs. Adrenergic Receptor
1) Adrenergic Axon - A nerve fiber that secretes NE
2) Adrenergic Receptor - A receptor that binds to NE or Epi
Preganglionic vs. Postganglionic?
1) Preganglionic - Cell body located CNS (brain or spinal cord) and carries msg to the autonomic ganglia, axon is myelinated, always releases ACh to a nAChR on the postganglionic cell.
2) Postganglionic - Cell body located outside the CNS (in an autonomic ganglion) and carries msg to the visceral effector organ, axon is unmyelinated, can release adrenergic or muscarinic.
Where are the sympathetic preganglionic neuronal cell bodies located?
In the intermediolateral of the spinal cord arising from T1 to L2 or L3 segments aka the Thoracolumbar outflow.
Characteristics of the sympathetic preganglionic fibers?
1) They are short
2) Myelinated
3) They synapse in the sympathetic autonomic ganglia
4) 22 pairs of ganglia that lie on either side of the vertebral column
Postganglionic fibers primarily release NE as their neurotransmitter, except for the following…?
1) Sweat glands - Release ACh to mAChr
2) Blood Vessels - ACh is released to mAChr on skeletal muscle
(T/F?) The ratio of sympathetic pre to postganglionic fibers is 1:20?
True - preganglionic fibers issuing from the spinal cord may synapse with neurons of more than one sympathetic ganglion: aka defuse innervation.
Effects of the sympathetic nervous system?
1) Increase HR, BP and CO
2) Bronchodilation
3) Shunts blood away from intestines and other organs to muscles
4) Increase Blood glucose
Where are the cell bodies of the parasympathetic preganglionic fibers located?
At the brainstem and sacral S2 to S4 spinal nerves: aka the Craniosacral outflow.
Characteristics of the parasympathetic Preganglionic fibers?
1) They are long
2) Myelinated
3) Releases ACh to nAChr
Characteristics of Parasympathetic postganglionic fibers?
1) They are short
2) They release ACh to mAChr
The ratio of parasympathetic pre to posganglionic fibers is 1:1. Whats the exception?
The ratio of preganglionic vagal fibers to ganglion cells in the myenteric plexus is 1:8000.
Function of the following Cranial Nerves:
1) CN III (Oculomotor)
2) CN VII (Facial)
3) CN IX (Glossopharengeal)
1) CN III - Innervate the eye orbit
2) CN VII - Innervate the lacrimal, nasal, submaxillary and sublingual glands
3) CN IX - Innervate the parotid gland
List of anatomies under the control of CN X (vagus)?
1) Heart
2) Lungs
3) Esophagus
4) Stomach
5) Small intestine and upper colon
6) Liver and spleen
7) Gallbladder
8) Pancreas
9) Upper portions of the uterus
(T/F?) The parasympathetic nervous system is functionally more selective, discrete, and localized than the sympathetic nervous system?
True
Synthesis, storage and release of ACh occurs in the cytoplasm of______?
1) Preganglionic SNS and PSNS nerves
2) Postganglionic PSNS nerves
3) Postganglionic SNS nerves innervating sweat glands and certain blood vessels.
4) Skeletal NMJ
Effects of Botulinum Toxin on the ACh synthesis, storage and release process?
Botulinum Toxin blocks vesicular fusion and exocytosis release of ACh.
(T/F?) ACh, once released into the synaptic cleft, can also act on the presynaptic mAChR or nAChR to modify its own release?
True - This is in addition to binding to the mAChR or nAChR on the posynaptic cell.
Describe the metabolic/degredation of ACh?
Acetylcholinesterase (AChE) is the enzyme responsible for hydrolysis of ACh to choline and acetate. Choline is transported back into the nerve ending, where it is used for synthesis of new ACh.
Where are AChE found?
In the synapses of cholinergic neurons and postsynaptic end plates of the NMJ.
How fast can AChE hydrolyze ACh?
1 molecule of AChE can hydrolyze an estimated 30,000 molecules of ACh every minute into choline and acetate.
Besides AChE, which other enzyme breaks down ACh? Where is it found and what’s is primary significance to CRNAs?
Butyrylcholinesterase aka pseudocholinesterase or plasma cholinesterase. It’s mostly found in liver and plasma but also in low concentrations near ACh receptors. It is VERY important in the metabolism of Succynlcholine and Mivacurium.
Characteristics of Choligernic receptors?
1) Binded by ACh only
2) 2 Types - Nicotinic and Muscarinic
Nicotinic vs. Muscarinic?
1) Nicotinic - Ligand gated (allows permeability to Na+, Ca+, and K+ ions resulting in depolarization and excitation), fast responses, 2 types (Nn and Nm)
2) Muscarinic - G-protein coupled receptors, slow responses.
