Flashcards in Autonomic Nervous System Deck (63):
What are the 3 major divisions of the autonomic nervous system?
Where is the sympathetic nervous system located?
- Thoracic spinal cord
Where is the parasympathetic nervous system located?
- Cranial nerves
- Sacral spinal cord
Where is the enteric nervous system located?
- In the gut
What type of system is the enteric nervous system?
- Efferent effector
What 2 structures control the enteric nervous system?
- Solitary nucleus in brain stem
What are the 4 methods by which preganglionic fibers of the sympathetic nervous system project?
- Enter chain ganglion, and synapse on post ganglionic neurons
- Enter chain, and ascend to another level before synapsing
- Enter chain and descend to another level before synapsing
- Go through chain, and join splanchnic nerves to synapse on prevertebral ganglia
Where do the preganglionic fibers of the sympathetic nervous system originate from?
- T1 - L1 from beta cells in lateral horn (intermediolateralis - lamina 7)
What do preganglionic fibers of the sympathetic nervous system do before synapsing on post ganglionic neurons?
Do sympathetic or parasympathetic neurons synapse closer to the spinal cord?
What is the ratio of preganglionic to postganglionic fibers in the sympathetic nervous system?
What fiber type comprosises less than 20 % of the total visceral fibers in the sympathetic nervous system?
- General Visceral Afferent
What neurotransmitter is released by preganglionic and postganglionic fibers in the sympathetic nervous system?
Are pre or postgangionic fibers heavily myelinated in the sympathetic nervous system?
Are pre or postganglionic fibers lightly myelinated in the sympathetic nervous system?
What type of stimuli is brough by stimulation of GVA fibers int he sympathetic nervous system?
What type of cells are the pre-ganglionic fibers of the sympathetic nervous system?
How do the beta cells of the sympathetic nervous system exit the spinal cord?
- Leave ventral horn through ventral route, and enter chain ganglion to synapse
What type of sympathetic fiber does not synapse within the chain?
What cranial nerves make up a portion of the parasympathetic nervous system?
3, 7, 9, 10
Which sacral segments make up a portion of the parasympathetic nervous system?
S2 - S4
Where are the post ganglionic neurons of the parasympathetic nervous system located?
- In the structures that they innervate
How are general visceral afferent fibers different in the parasympathetic nervous system compared to the sympathetic?
- More abdundant and innocuous
What neurotransmitters are released by the preganglionic and postganglionic fibers of the parasympathetic nervous system?
What is the ratio of pre-ganglionic to post-ganglionic fibers in the parasympathetic nervous system?
What type of nerve fiber is not found below L3 or above T1?
- General visceral efferents
What 3 structures are innervated by the enteric nervous system?
- GI tract
- Gall bladder
Does the enteric nervous system function autonomously?
Yes, but it can be regulated by the sympathetic and parasympathetic nervous systems
What is a plexus?
- Meshwork of ganglia and interconnecting nerve fibers located between the various layers of muscle and endothelium
Where is the myenteric plexus found?
Between external longitudinal and circular smooth muscle layers
Where is the submucosal plexus found?
- Within the connective tissue of the submocusa between the circular muscles and mucosa
What is another name for vasodepressor syncope?
What is neurogenic shock?
- Vasodilation of muscles diverts blood to muscles, causing a lack of blood flow to the brain
- Caused by strong emotions that drive sympathetic nervous system
- Syncope occurs
What are the 3 general types of innervation to the bladder?
What 4 portions of the cortex have an influence on bladder innervation?
- Anterior cingulate cortex (ACC)
- Pre-frontal cortex
What tract sends information regarding bladder innervation to the cortex and periaquidcutal gray?
Lateral spinothalamic tract
What is the function of the periaqueductal gray?
- Stimulates activation of center 2 in the Pons
What is the function of center 2 in the Pons?
Stimulates the sympathetic nervous system, which:
- Relaxes the detrussor muscle through inhibition of the parasympathetic, and inhibition directly to the muscle
- Stimulates the internal urethral sphincter
Also inhibits center 1
What is the function of center 1 in the Pons?
Stimulates the parasympathetic nervous system, which:
- Stimulates contraction of the destrussor muscle
What spinal cord segments work with center 1?
S2 - S4
What spinal cord segments work with center 2?
T1 - L1
What nuclei work with center 2?
- Onuf nuclei
What is the function of the somatic nervous system in the bladder?
- Stimulates external uretheral sphincter
What is the term for reflexive bladder pathology?
- Uninhibited reflex neurogenic bladder
What is uninhibited reflex neurogenic bladder?
- Voluntary control of filling and emptying of bladder is lost
- No concious perception of bladder filling or emptying
- Bladder fills and empties reflexively
At what level do bladder reflexes occur?
What type of lesion will cause uninhibited reflex neurogenic bladder?
- Bilateral frontal lobe lesion
How can uninhibited reflex neurogenic bladder be controlled?
Is uninhibited reflex neurogenic bladder an Upper or Lower Motor Neuron lesion?
What are the symptoms of Automatic Bladder?
- Micturition control is lost
- Bladder empties incompletely
Why does the bladder empty incompletely in Automatic Bladder?
- Reflex pathways that trigger pontine micturition is gone
- Each time the bladder is stretched, it empties (not when completely stretched)
What is the location of a lesion that will cause automatic bladder?
- Bilateral spinal cord lesion above sacral levels
What systemic changes can occur in Automatic Bladder?
- Blood pressure
- heart changes
What are major symptoms of Non-Reflexive Bladder?
- Bladder fills to capacity and overflows --> dribbling
- Bladder wall is flaccid
What is the cause of non-reflexive bladder?
- Sacral reflex arc lesioned
Where is the location of the lesion in non-reflexive bladder?
- Bilateral lesion to sacral cord or pelvic nerves
What renal complication may arise from non-reflexive bladder?
What center controls the defecation reflex?
- Hypothalamic autonomic center
What 2 structures make up the hypothalamic autonomic centre?
- Mesencephalon pons
- Dorsal motor nucleus
What 2 parasympathetic nerves stimulate defecation?
- Pudendal nerve
- Vagus nerve
What sympathetic nerve inhibits defecation?
- Hypogastric nerves
What spinal segments facilitate defecation?
S2 - S4