Lecture 32+33: Clinical Autonomic Nervous System

Question 1

Parasympathetic division: anatomy
Craniosacral origins

Answer 1

• III>pupillary constrictor, ciliary body
• VII>lacrimal gland, some salivary glands
• IX>salivary glands
• X>thoracic and abdominal viscera
• S1-3> pelvic viscera (pelvic n.)

Question 2

Sympathetic division: anatomy

Answer 2

Arises from the thoracolumbar spinal cord segments (t1-L3/4)
T1-6: head
T1-2: eye (sympathetic innervation loss)

Question 3

Parasympathetic and pupil

Answer 3

Parasympathetic nucleus of III
Oculomotor nerve
Ciliary ganglion (synapse)
Post ganglions: short ciliary nn

Question 4

Sympathetic and pupil

Answer 4

T1-T2
Vagosympatheitc trunk
Synapse in cranial cervical ganglion
Post ganglionics pass through middle ear

Question 5

Horners syndrome (a group of signs)

Answer 5

Signs associated with loss of symp input to ocular structures
* Miotic pupil, decreased tone to pupillary dilator muscle
* Enopthalmos, eye has sunk back a bit, decrease to tone to perioorbita
3rd eyelid protruding decrease tone to periorbita
* Ptosis, dropping of upper eyelid and decrease tone to m. levator palpebrae superioris

Question 6

Horner’s syndrome in horses

Answer 6

can ALSO produce hyperhidrosis (excessive sweating) in denervated skin. Sweat glands in horses are regulated by regular adrenergic sympathetics, in us it’s cholinergic sympathetics.

Question 7

Micturition

Answer 7

The function of urinary bladder= (takes sympathetic and parasympathetic input)
* Filling (storage) phase
* Emptying phase (micturition)
Both require:
* Sympathetic input (hypogastric n.)
* Parasympathetic input (pelvic n.)
* Filling - dominated by sympathetic tone
* Emptying - dominated by parasympathetic tone

Question 8

what are the two functionally coordinated parts of LUT (lower urinary tract):

Answer 8

1. Urinary bladder (detrusor m., smooth m. in urinary bladder wall)
2. Urethral outflow tract
   
   • Internal sphincter (smooth m.) - not that strong
   • External sphincter (striated m. = m. urethralis, voluntary control)

Question 9

what is necessary for filling and emptying of bladder

Answer 9

Filling =
Relaxation of detrusor
Contraction of sphincters
Emptying =
Contraction of detrusor
Relaxation of sphincters

Question 10

what 3 sets of nn are involved in micturition

Answer 10

Events coordinated by 3 sets of nn:
Pelvic nn (parasympathetic)
Hypogastric nn. (sympathetic)
Pudendal nn. (voluntary) - only urethralis m.

Question 11

what to give to improve urinary leakage

Answer 11

alpha 1 agonists

Question 12

the pons and its involvement in micturition

Answer 12

The pontine micturition center
Without the pons, would not have normal emptying of the urinary bladder

Question 13

Disorders, parasympathetic, micturition

Answer 13

comes via S1-S3…
Damage to this area only allows filling and no emptying. The urethralis m also comes from S1-S3 so becomes flaccid.
Bladder becomes distended w/ urine
Overflow incontinence (easily expressed)
S1-S3 is Lower motor neuron bladder
Prone to bladder infections - think also that it can get to kidneys and then the system and cause septicemia

Question 14

Disorders of micturition

Answer 14

Injury to descending pathways (cranial to sacral cord)
T13-L1 damage is common (upper motor neuron bladder)
So what does this bladder look like?
Local reflex arcs are still in place, but pontine micturition is disrupted…
Voluntary emptying cannot be initiated, reflex emptying cannot be prevented
Hypertonia in m. urethralis = difficulty initiating and sustaining emptying
May present with large bladder which partially empties reflexively with manual expression
OR as a small bladder which partially empties reflexively frequently