chapter 15 autonomic NS Flashcards
what are the two categories of the autonomic nervous system
sympathtic and parasympathetic
what is the voluntary/somatic effector vs the autonomic effector
somatic–> skeletal muscle
autonomic–> cardiac, smooth muscle, and glands
how many motor neurons from the CNS to the effector in somatic motor division
1, lacks ventral ganglia
how many motor neurons between CNS and effector in the autonomic motor division
2 motor neurons between CNS and effector, ganglion where pre and post motor neurons connect (i.e. there is a ganglion on the anterior)
what is the excitatory neurotransmitter at the effector in the somatic motor division
ACh
in the parasympathetic system what is the neurotransmitter released and when
ACh is the only neurotransmitter involved in the parasympathetic system. It is released from the preganglionic synapse (just like in the sympathetic nervous system) and again from the postganglionic synapse
in the sympathetic nervous system what neurotransmitters are released and when
ACh is released by the preganglionic synapse (just like parasympathetic system) and norepinephrine is released from the postganglionic synapse
what makes the autonomic system excitatory or inhibitory
it depends on the types of receptors on the effector organs
what does the parasympathetic system activate
“rest and digest”
what does the sympathetic system activate
“fight or flight”
where is the cell body of the preganglionic neuron in the parasympathetic system
usually in the brainstem or sacral spinal cord (CNS)
where is the cell body of the postganglionic neuron in the parasympathetic system
usually in a ganglion near the target organ (PNS)
where are the cell bodies of preganglionic neurons in the sympathetic system
usually in the spine (CNS)
where are the cell bodies of postganglionic neurons in the sympathetic system
in a sympathetic ganglion, located next to the spinal cord (PNS); T1-L2
are there dorsal root ganglion in both voluntary and autonomic NS
yes
describe the preganglionic axon in the parasympathetic NS
thin, lightly myelinated. super long. deads ends at the ganglion, usually inside an organ or just outside of the organ it’s innervating
describe the postganglionic axon in the parasympathetic NS
very thin, unmyelinated. short
describe the preganglionic neuron in the sympathetic NS
lightly myelinated, thin, very short
describe the postganglionic neuron in the sympathetic NS
very long, from the sympathetic ganglion chain to the organ it innervates. Slow transmission so we can effectively inhibit fight or flight response if not needed
which NS has a special group of neurons that emerge from the rami comunicante, do not synapse in the ganglion chain, directly attach to the adrenal medulla (only 1 neuron, no pre or post), and initiate a rapid fight or flight response
sympathetic
which autonomic division contricts pupils, focuses lens, normal secretion of lacrimal and salivary glands, reduces heart rare, secretion of bile, GI and pancreatic motility and secretions, defication and urination, vasodilation
parasympathetic
where do preganglionic axons pass through? and where do they enter?
through the rami communicante and enter the paravertebral ganglionic chain
what is the paravertebral ganglionic chain?
location of postganglionic cell bodies
what are the 3 ways a preganglionic axon can synapse
1 synapse at same level with postganglionic neuron
2 ascent/descent and then synapse with the postganglionic neuron
3 pass through without synapsing, instead form splanchnic nerve. Then synapse in prevertebral ganglia (anterior) [some may pass through prevertebral chain and go directly to adrenal medulla]
where does the postganglionic axon synapse
target organ (is a long fiber)
give some examples of “stress responses” from the sympathetic division
dilates pupil, shuts down gland secretions, bronchial dilation, increased heart rate and force, redices GI motility and constricts sphincters, stimulates adrenal medulla which then stimulates release of glucose into blood by liver, vasocontriction, heart and muscle vessels dilate
what does the adrenal medulla secrete
norepi and epinephrine
what does the adrenal medulla do
“surge of adrenaline”
what are visceral reflexes
equivalent to somatic reflex arcs
purpose is to recieve/responds to info about: chemical changes, strethc, and viscera irritation
where are visceral sensory cell bodies found
dorsal root ganglia, sensory ganglia of cranial nerves, sympathetic ganglia
What leads to referred pain
visceral affarents traveling with somatic pain affarents
what is referred pain
pain fro the viscera are percieved as coming from skeletal muscle
what is the enteric nervous system
compltete 3-neuron reflex arcs in GI tract
where is ACh found
cholinergic fibers
somatic motor neurons
all autonomic preganglionic axons
parasympathetic postganglionic axons
where is norepinephrine found
adrenergic fibers
sympathetic postganglionic axons and adrenal gland
what is a cholinergic receptor
responds to acetylcholine
what are two types of cholinergic receptors
nicotinic and muscarinic
what do nicotinic receptors do
always excitatory for acetylcholine
what do muscarinic receptors do
excitatory or inhibitory to acetycholine
excitatory–>blood vessel dilation
inhibitory–> heart muscles (slows down so HR isnt out of control)
what are adrenergic receptors
responds to norepinephrine, and found at most sympathetic target organs
what are the 2 classes of adrenergic receptors
alpha and beta
what does an alpha adrenergic receptor do
mostly excitatory: vasocontricts blood vessels, contricts GI and sphincters, dilates eye pupils
what do beta adrenergic receptors do
mostly inhibitory (except on heart where they increase heart rate and force): vasodilation in heart and lungs, bronchial dilation, inhibition of muscles in GI tract
what type of innervation are sweat glands
sympathetic only
why are blood vessels to sweat glands adrenergic
need vasodilation to offload heat and cause sweating
is dual innervation of both sympathetic and parasympathetic normal/common
yes
name some ways the sympathetic division aids in thermoregulation
blood vessel dilation, sweat glands, arrector pili muscle
which division aids in release of renin from kidneys and what does it do
sympathetic division. renin promotes blood pressure increase
what are the metabolic effects of the sympathetic division being activated
increased metabolic rate of cell (more ATP being used), increases blood glucose levels, recruits rats for fuel use, increases mental alertness via the reticular activation system
give a summary statement of the effects of the parasympathetic system
short-lived, localized effects
give a summary statement on the effects of the sympathetic system
effects are diffused across the body and organ systems, highly interactive effects
describe hypertension
overactive sympathetic vasoconstriction due to chronic stress: heart works harder, increased wear and tear on blood vessels
describe orthostatic hypotension
commonly seen in elders as their autonomic NS becomes less reliable: if stand too quickly they faint because vasoconstrictors couldnt rapidly counter sudden change (drop) in blood pressure
