Peripheral Nervous System Flashcards
What are the two divisions of the autonomic nervous system
Sympathetic and Parasympathetic
How many neurons make up an autonomic pathway, and what are they called
2, preganglionic and postganglionic
Where do the cell bodies of preganglionic neurons lie
the spinal cord
Where do pre and post ganglionic neurons synapse
Ganglion
What is a ganglion
cluster of cell bodies outside of the CNS
Where are the sympathetic chain ganglia
just outside of the spinal cord, the point between where the dorsal root and ventral roots come together and before where the dorsal and ventral rami split
What is the collateral ganglia
It’s when the preganglionic neuron passes the chain ganglia without synapsing and synapses later.
What hormone is released by the parasympathetic preganglionic neuron
Acetylcholine
What hormone is released by the parasympathetic postganglionic neuron
Acetylcholine
What hormone is released by the sympathetic preganglionic neuron
Acetylcholine
What hormone is released by the parasympathetic postganglionic neuron
Norepinephrine
Epinephrine
What is a cholinergic receptor
receptors for ACH
What are the two types of cholinergic receptors
Nicotinic and Muscarinic
What is a nicotinic receptor
receptors at the synapse between pre and postganglionic neurons, they open cation channels (Na & K)
What is a muscarinic receptor
receptors between parasympathetic postganglionic neurons, they initiate cell signaling cascades
What is an adrenergic receptor
Receptor for norepinephrine and epinephrine
What are the two types of adrenergic receptors
alpha and beta
what are the subtypes of alpha and beta adrenergic receptors
alpha 1 and alpha 2
Beta 1 and Beta 2
nicotinic receptor steps
- ACH binds to receptor
- Na and K channel opens
- Na diffuses into the cell
Muscarinic receptor steps (heart)
- ACH binds to receptor
- G-protein subunits break off
- G-protein binds to K channel, opening it
- K diffuses out of the cell
What is the phrase for the sympathetic nervous system
Fight or flight
What is the phrase for the parasympathetic nervous system
Rest and digest
What is the effect of the sympathetic nervous system on the heart
Increases heart rate
increases conduction velocity
increases force of contraction
What is the effect of the parasympathetic nervous system on the heart
decrease heart rate
decreases conduction velocity
decreases force on contraction
What is the effect of the sympathetic nervous system on the blood vessels
vasoconstriction (except to brain, none)
vasodialiation with epinephrine
What is the effect of the parasympathetic nervous system on the blood vessels
none
What is the effect of the sympathetic nervous system on the stomach, intestines
decreased motility, inhibits secretion, and contracts sphincters
What is the effect of the parasympathetic nervous system on the stomach, intestines
increased motility, promotes secretion, and relaxes sphincters
What is the effect of the sympathetic nervous system on the lungs
inhibits secretions and causes relaxation
What is the effect of the parasympathetic nervous system on the lungs
promotes secretions and causes contraction
What is the effect of the sympathetic nervous system on the adrenal medulla
stimulates renin release
What is the effect of the parasympathetic nervous system on the adrenal medulla
none
What is the effect of the sympathetic nervous system on the liver
stimulates glycogenolysis and glucogenesis
What is the effect of the parasympathetic nervous system on the liver
none
What is the effect of the sympathetic nervous system on the adipose tissue
stimulates lipolysis
What is the effect of the parasympathetic nervous system on the adipose tissue
none
What is a sympathetic agonist
drug that mimics the effects of Norepinephine
What is a sympathetic antagonist
drug that blocks the effects of Norepinephrine
What is a parasympathetic agonist
drug that mimics the effects acetylcholine
What is a parasympathetic antagonist
drug that blocks the effects of acetylcholine
What does the somatic nervous system refers to
The innervation of skeletal muscle
What is a reflex
a response to stimulus that occurs without conscious effort
what are the two kinds of reflexs
innate and conditioned
What is an innate reflex
a reflex that we are born with (not learned)
what is a conditioned reflex
a reflex that is the result of practice and learning
What are the 5 components of the reflex arc
- sensory receptor
- afferent pathway
- integrating center
- efferent pathway
- effector
what is the strecth reflex and how does it work
monosynaptic reflex, the streching muscle causes the receptor (muscle spindle) which detects lengthening or shortening of a muscle. this fires causing the strecthed muscle to contract (shorten again) it also inhibits the contraction of the opposing muscles
What is the withdrawl and crossed extensor reflex and how does it work
when a painful stimulus occurs, like stepping on a tack, the receptor sends a message up to the CNS then it comes back down and causes the (foot) to withdraw from the painful stimulus. The other leg is stimulated (crossed extensor reflex) to extend and provide the support that would have been provided by the other leg.
