Term
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Definition
1) parasymp NS (PSNS)
* rest and digest
*non-excitatory, relaxation for the most part, homeostasis
2) symp NS (SNS)
*fight or flight
The ANS is ONLY a motor syst, it starts and ends in the CNS |
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Term
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Definition
• Innervates ALL blood vessels, glands, viscera
• Each of these receives both
sympathetic and parasympathetic innervation
- Tend to have opposite effects
• Effect on organ depends of which
receptor is present and activated
• Both systems have a pre- and post-
ganglionic fibre with a synapse in a
ganglion somewhere en route to
targets. |
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Term
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Definition
Pre-ganglionic neuron
=> From brain/spinal cord to ganglion
*note that this 1st neuron is not synapsing on a musc, it is synapsing on a ganglion in another neuron
Ganglion
= collection of neurons outside CNS
Post-ganglionic neuron
=> From ganglion to organ |
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Term
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Definition
| wiring is similar in both but different in the way tiss discriminates, has to do w/ how it responds to NT secreted by syst |
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Term
| Sympathetic Division Organization |
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Definition
• 1st neuron (pre-gang) is always secreting ACh
• ACh travels across synapse and interacts w/ nictonic AChRs
• usually secrete NE, but theres some special cases (glands) |
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Term
| Parasymp Division Organization |
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Definition
• 1st neuron (pre-gang) is always secreting ACh
• ACh travels across synapse and interacts w/ nictonic AChRs
• post-gang secrete AcH (both pre and post are secreting ACh) |
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Term
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Definition
SYMP DIVISION
• 1st neuron (pre-gang) is always secreting ACh
• ACh travels across synapse and interacts w/ nictonic AChRs
• secrete NE |
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Term
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Definition
SYMP DIVISION
only for adrenal galnds
• in adrenal medulla, ACh travels across synapse but reaches an imature neuron (nest cells)
• they will secrete E/NE directly into the blood stream |
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Term
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Definition
SYMP DIVISION
only in glands
• 1st neuron (pre-gang) is always secreting ACh
• ACh travels across synapse and interacts w/ nictonic AChRs
• secrete ACh |
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Term
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Definition
PARASYMP DIVISION
• pre and post secreting ACh |
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Term
| Receptors of the PSNS and SNS |
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Definition
| different receptor types allows to have variety of func a syst can perform. same NTs working on diff receptors |
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Term
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Definition
rest and digest- predominant when at rest
animal in homeostasis
responsible for basal func of organs |
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Term
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Definition
decrease heart rate
increase intestinal mobility
increase gland secretion
allows urination/defecation |
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Term
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Definition
Cranio-sacral outflow (PSNS fibers leave CNS in 2 places):
• Cranial nerves III, VII, IX, X
• Sacral spinal cord segments S1-S3 (pelvic
nerve)
-usually innervates the most caudal part |
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Term
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Definition
• Ganglion located near target organ
-Long pre-ganglionic fibers
-Short post-ganglionic fibers
• Numerous small ganglia located very
close to targets |
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Term
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Definition
Nicotinic ACh receptors: Bind acetylcholine (Ionotropic) --> dont really need to know
• Present in ganglia: both sympathetic and parasympathetic
• Present on somatic striated muscles
• Ionotropic receptors: entry of sodium
Muscarinic ACh receptors: Bind acetylcholine (Metabotropic) --> need to know
• G-protein coupled receptors (metabotropic)
• 5 different types: M1-M5
-all Excitatory except M2 and M4 (inhibitory) |
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Term
Muscacnaric receptors
(all I need to know) |
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Definition
M 1,3,5 = activate
M 2,4 = relaxing |
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Term
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Definition
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Term
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Definition
• inc heart rate
• redistributes blood to specific organs (skeletal musc vs skin,kidney)
•dilates pulmonary bronchioles
• dec intestinal mobility
• inhibits urination/defecation |
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Term
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Definition
Thoraco-lumbar “outflow”
• Spinal cord segments T1-L5
• symp ONLY come out T1 and upper lumbar (species dependent)
• just know, thoracolumbar spine segments is where they exit |
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Term
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Definition
• Some ganglia are located near spinal
cord – “paravertebral” ganglia.
• Others are in neck (cervical) and
abdominal cavity (mesenteric, celiac
ganglia – these are sometimes called
“prevertebral” ganglia)
- Shorter pre-ganglionic fibers
- Longer post-ganglionic fibers
NOTE: they can both be pretty long relative to PSNS |
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Term
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Definition
Nicotinic ACh Receptors
• Present in ganglia between pre- and post-ganglionic fibres: similar to parasympathetic
(Note, similar receptor type to neuromuscular junctions in somatic muscles)
Muscarinic ACh Receptors
• Innervate Glands – DO NOT NEED to know more than this fact.
Adrenergic Receptors (diff types do diff things)
• Bind epinephrine and norepinephrine
• G-protein coupled receptor (metabotropic)
• α1, α2
• β1, β2, β3
• all Excitatory except α2 and β2 (inhibitory --> cause things to relax, ie tiss that need more blood flow/lungs) |
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Term
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Definition
Smooth muscles
• Blood vessels, dilator muscle pupil
• Internal sphincter bladder
Constriction |
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Term
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Definition
Heart
Increases heart rate
Increases force of contraction |
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Term
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Definition
Smooth muscles
• Blood vessels (muscles)
• Bronchioles
• Detrusor (bladder)
• Gastrointestinal tract
• Uterus
Relaxation
• Increases blood flow
• Bronchodilation
• Relaxes bladder
• Decreases intestinal motility and
uterine contractions |
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Term
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Definition
• depends on type of receptor present
• when SNS is stim --> release of NE/E
• will then bind to receptors on:
-bv that innervate skeletal musc (β2) => inc blood flow
-skin, kidneys (α1) => decreased blood flow
•allows temporary redistribution of blood to necessary organs to run or fight |
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Term
| ANS innervation of the eye |
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Definition
• Size of the pupil is controlled by Autonomic Nervous
System
- Constriction: Parasympathetic
- Dilation: Sympathetic |
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Term
| how PSNS mediates constriction |
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Definition
| optic n (CN2) --> pretectal Nuc --> interneuron --> PSNS Nuc of oculomotir (CN 3) --> ciliary gang of CN 3 --> iris sphuncter -->constrict (when activated) |
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Term
| how SNS mediates dilation |
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Definition
| hypothalamus => rostral colliculus (midbrain) ==> down the spinal cord to T1-T3 segs ==> Axons exit spinal cord, travel through brachial plexus ==> synapse in cranial cervical ganglion ==> Axons ascend to the eye in vagosympathetic trunk and peripheral nerves ==> Dilator muscle constricts when activated |
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Term
| Clinical Application of Eyes and ANS innervation |
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Definition
Assessment: Symmetry of pupils, pupillary light reflexes
⇒Inability to constrict : lesion of parasympathetic pathway
⇒Inability to dilate: lesion of sympathetic pathway
- Also called Horner’s Syndrome |
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Term
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Definition
• Can result from lesions anywhere in
sympathetic pathway to the (iris) Eye/Face
• Most common with brachial plexus lesions or
middle ear lesions (otitis – because nerves
travel through middle ear en route to eye). |
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Term
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Definition
• Miotic pupil
• Enopthalmos (sunken eye in dogs, cats: loss
of sympathetic innervation in orbital area)
• Partial protrusion of 3rd eyelid
- 3rd eyelid prolapsed
• Lack of sweating on affected side of face
(horses)
• if you shine a light in the good or bad eye, the good eye will dilate lrger |
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Term
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Definition
anisocoria = parasymp problem w/ oculomotor n
Horner's = SNS prob |
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Term
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Definition
• The Neurologic Control of Urination
• Urination is controlled by a combination of voluntary and involuntary pathways through the autonomic and somatic nervous systems which are influenced by control from the cortex.
- Involuntary: Autonomic Nervous System – Bladder contraction, Internal
sphincter control
- Voluntary: Somatic Nervous System – External sphincter control
• Neurological disorders can result in incontinence leading to loss of normal control of micturition
- micturition issues fall between motor func and deep pain
• not really a reflex, we have conscious and unconscious control |
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Term
| Lesions that can lead to micturition |
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Definition
lesions in any areas of the NS can potentially cause probs w/ micturition:
Damage to the pelvic nerve or spinal cord or pons
= flaccid bladder, no tone
• due to effects on the sensory and motor tracts that innervate the detrusor.
Damage to the spinal cord above the sacral segments
= “spastic” sphincter (contracts more than it should)
• due to loss of UMNs in tracts that influence the activity of the sphincter reflex.
Damage to the pudendal nerve or sacral segments of the spinal cord
= “flaccid” sphincter
• due to damage to somatic LMNs that innervate the sphincter.
Damage to the cortex
= loss of the Conscious Storage phase.
• The animal urinates whenever the bladder becomes full. |
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Term
| If there signs of motor damage to spial cord... |
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Definition
Tracts controlling micturition are damaged
around the same time, or just after, motor injury, so whenever you have signs of motor
damage to the spinal cord (eg. in disc disease etc.) you should consider whether the animal
can urinate properly and not have an overfilled bladder. |
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Term
| hierarchy of signs with spinal cord injury |
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Definition
| proprioceptive tracts most sensitive, then motor, then pain |
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Term
| REVIEW LECTURE NOTES ON MICTURTION |
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Definition
| REVIEW LECTURE NOTES ON MICTURTION |
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