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.