Autonomic Nervous System Flashcards
Select the correct matching pair:
A) Upper motor neuron injury: Fasciculations
B) Lower motor neuron injury: Pathological reflexes
C) Lower motor neuron injury: Marked muscle atrophy
D) Upper motor neuron injury: Decreased muscle tone
C
Select the true response:
A) Lower motor neurons are the only means by which a muscle can be moved
B) Lower motor neuron cell bodies are in the posterior horn of the cord
C) A lower motor neuron only innervates one muscle fiber and this is known as a motor unit
D) The cerebellum exerts direct control of lower motor neurons
A
Select the true response about the corticospinal tract:
A) All of the fibers in this tract arise from cell bodies in the primary motor cortex
B) Contains some fibers arising from cell bodies in the premotor area but none from the parietal lobe
C) Fibers destined for the lower extremity arise from cell bodies located in lateral aspect of the primary motor cortex
D) Crosses midline at spinomedullary junction
D
A patient has weakness on the left side. Which lesion could account for this? A) Left lateral funiculus B) Left posterior funiculus C) Left pyramid D) Left cerebral peduncle
A
B&C would affect the right side due to the decussation
A patient has weakness on the right side. What lesion could account for this? A) Left anterior midbrain B) Right anterior basis pontis C) Right anterior rostral medulla D) Left lateral funiculus
A (it has not decussated yet)
What are some effects of the parasympathetic nervous system?
“rest or digest”, enhances energy STORAGE;
- decreases cardiac output, blood pressure
- increase gut peristalsis, salivation, pupillary constriction and bladder constriction
What are some effects of the sympathetic nervous system?
“fight or flight”, energy needs to be EXPENDED
- increases heart rate
- decreases peristalsis
- blood from gut to muscles
- adrenal gland can dump epinephrine into circulation so widespread, long-lasting effects possible
What does the autonomic nervous system control?
Visceral activity
What do both the somatic and autonomic nervous systems both have?
- Visceral sensory fibers
- Ascending pathways
- Descending pathways control motor neurons
- Reflexes
What are some differences between the somatic and autonomic nervous systems?
- The autonomic nervous system if from the limbic system and the hypothalamus (not thalamus) is the main control system.
- Sympathetic and parasympathetic efferents do not reach their targets directly: a 2-neuron chain is involved. (preganglionic cell body in CNS & postganglionic neuron in ganglion
Describe the preganglionic and postganglionic fibers of both sympathetic and parasympathetic.
Preganglionic fibers are thin myelin
Postganglionic fibers are unmyelinated
Where are the ganglia for sympathetic and parasympathetic systems located?
Sympathetic: near CNS
Parasympathetic: near or in the walls of innervated organ
What neurotransmitters are used in the first and second synapse of parasympathetic pathways?
-Acetylcholine (1st: nicotinic, 2nd: muscarinic)
What neurotransmitters are used in the first and second synapse of sympathetic pathways?
- First synapse is Acetlycholine (Nicotinic) (but different receptors than those in parasympathetic)
- Second synapse is Norepinephrine (mostly, but sweat glands are Acetylcholine)
Where are preganglionic fibers for the sympathetic system located?
-From T1 to L2/3 segments
Describe the pathway traveled for sympathetic fibers once they leave the spinal cord (CNS).
-Travel in spinal nerve to sympathetic chain, prevertebral ganglia, or adrenal gland
Where are preganglionic neurons for the parasympathetic system located?
-In brainstem (CN’s 3,7,9,10) and sacral cord (Pelvic splanchnic nerves)
Describe the pathway traveled for parasympathetic fibers.
-Travel in cranial nerves and sacral nerves. Outflow to thoracic, abdominal and pelvic viscera. (NONE to limbs)
Bronchial muscles, lung:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-5
- Relax
- DMNX
- Contract
Heart rate/ output:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-5
- Increase
- Nucleus Ambiguus (CN X)
- Decrease
Arteries (muscle):
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-L3
- Most constrict, few can dilate
- 4.
Arteries (skin):
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-L3
- Constrict
3.
4.
Arteries (viscera):
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-L3
- Constrict
3.
4.
GI motility:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T6-L3
- Decrease
- DMNX
- Increase
GI sphincters:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T6-L3
- Contract
- DMNX
- Relax
Bladder detrusor:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T12-L2
- Relax
- S2-4
- Contract
Bladder sphincter (internal):
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T12-L2
- Contract
- S2-4
- Relax
Seminal vesicles, vas deferens:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T10-L1
- Contract (ejaculation)
3.
4.
Penile/clitoral arteries:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T10-L1
- Constrict, can dilate (depends)
- S2-4
- Dilate (erection)
Adrenal medulla:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T8-L1
- Increase secretion
- 4.
Pupillary sphincter:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
1.
2.
3. Edinger-Westphal nucleus (CNIII)
4. Contract (miosis)
Pupillary dilator:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-3
- Contract (mydriasis)
3.
4.
Superior tarsal:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-3
- Contract (lid elevates)
3.
4.
Ciliary muscle:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
1.
2.
3. Edinger-Westphal nucleus (CNIII)
4. Contract (accommodation)
Lacrimal gland:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-3
- Slight Increased secretion
- Superior Salivary Nucleus (in pons)
- Increased secretion
Salivary gland:
- Location of preganglionic sympathetic neurons
- Sympathetic effect
- Location of preganglionic parasympathetic neurons
- Parasympathetic effect
- T1-3
- Slight increased secretion, increased viscosity
- Inferior (medulla) and Superior (pons) salivary nucleus
- Increased secretion, decreased viscosity
Select the true response:
A) Postganglionic parasympathetic fibers are myelinated
B) Parasympathetic ganglia occur near or in the organ of innervation
C) The sympathetic division only uses norepinephrine as a neurotransmitter
D) Sympathetic nuclei in the brainstem include cranial nerve III
B
Describe the location of parasympathetic preganglionic and postganglionic cell bodies for Occulomotor nerve (CN III).
Preganglionic: Edinger-Westphal nucleus (in midbrain-medial)
Postganglionic: Ciliary ganglion
- Pupillary constrictor muscle fibers (pupillary reflex)
- Ciliary muscle (accommodates lens for near vision) (more circular lens)
Describe the location of parasympathetic preganglionic and postganglionic cell bodies for the Facial nerve (CN VII).
Preganglionic: Superior salivary nucleus in tegmentum of pons
Postganglionic:
- Pterygopalatine ganglion: terminates in nasal and lacrimal glands
- Submandibular ganglion: terminates in submandibular and sublingual salivary glands
Produces thin and watery mucous
Describe the location of parasympathetic preganglionic and postganglionic cell bodies for the Glossopharyngeal nerve (CN IX).
Preganglionic: Inferior salivary nucleus in medulla
Postganglionic: Otic ganglion
-Terminates in Parotid salivary gland
Produces thin and watery mucous
Describe the location of parasympathetic preganglionic and postganglionic cell bodies for Vagus nerve (CN X).
Preganglionic: Medulla
1. Dorsal motor nucleus of Vagus (DMNX)
*Serve GI tract and Gut derivatives
(increases gastic secretion and peristaltic activity)
- Nucleus Ambiguus: serve the heart, lungs
(reduces heart rate and blood pressure)
Postganglionic: Wall of target tissue
*Viscera from thorax to transverse colon
(lower esophagus, stomach, ascending colon, pancreas, liver)
(these fibers don’t leave a named ganglion bc there are soo many)
Describe the location of parasympathetic preganglionic and postganglionic cell bodies for the sacral parasympathetic outflow (Pelvic splanchnic nerves).
Preganglionic: S2-4 level, region of lateral horn
(Does not make discrete anatomical horn)
Postganglionic: Wall of target tissue
- Viscera from transverse colon to rectum
- Includes bladder, uterus, genitals, gonads, etc.
- these take over where the vagus stops)
Select the correct matching pair: A) Superior salivatory nucleus: IX B) Edinger-Westphal: IV C) Nucleus ambiguus: X D) Inferior salivatory nucleus: VI E) Selena Gomez: Justin Bieber
C (in medulla, also DMNX)
Where are preganglionic sympathetic fibers located?
Thoracic Spinal cord (lateral horn) levels T1-L2/3
Preganglionic sympathetic nerve fibers leave the ventral root and can do what 4 things?
- Synapse in nearest ganglion
- Ascend chain, synapse in superior (head/neck) or middle cervical ganglia
- Descend chain, synapse in lumbar/sacral ganglia
- Traverse chain, emerge as splanchnic nerves (pre vertebral/collateral ganglia) supply fibers to pelvic and abdominal viscera
What connects the sympathetic trunk to the spinal nerves?
White and gray communicating rami
travel to sympathetic chain on white rami, travel back to spinal nerve on gray rami
Where are white and gray communicating rami located?
White communicating rami: T1-L2/3 spinal nerves
Gray communicating rami: All spinal nerves
How do postganglionic sympathetic fibers reach the head?
Cervical ganglia (superior) and Carotid plexus (on ICA)
Where to preganglionic sympathetic nerve cell bodies project to?
- Paravertebral (chain) ganglia
- Prevertebral (collateral) ganglia
- Adrenal medulla
Describe Horner Syndrome and its symptoms.
- Loss of sympathetic innervation to the face
- Ptosis (eyelid droop) (superior tarsal muscle)
- Miosis (small pupil)
- Endophthalmos (apparent sunken or deeper eye)
- Anhydrosis (dry skin) (loss sweat glands of face)
How is Congenital Horner syndrome different from Horner syndrome?
-They are the exact same except Congenital Horner Syndrome also has heterochromia (if before 2yrs old), which is when the eyes are different colors.
Describe referred pain.
- It is when pain from viscera is perceived as arising from the surface (somatic pain). This occurs when visceral structure is innervated by same cord level as surface structure.
- Mixing of signals at spinal cord and brainstem levels
- No somatotopic maps of viscera.
Give a few examples of referred pain (3).
- Heart pain during myocardial infarction referred to chest wall or down arm
- Intestinal pain referred to anterior abdominal wall
- Labor pains referred to sacral area and back
What is the function and innervation of the enteric nervous system?
- It is an independently functioning nervous system that provides innervation for:
1. Intestinal tract
2. Pancreas and gall bladder
*Provides primary control of motility and secretion
What does the neural plexus of the intestinal tract consist of? (2)
- Myenteric plexus (of Auerbach)
2. Submucous plexus (of Meissner)
