L10: ANS Intro Flashcards
The ANS is ______ consciously controlled
NOT
what is the major function of the ANS
maintain physiological homeostasis
(regulated CO, BP, blood flow, digestion, adrenal function, bronchodilation, etc)
rest and digest
parasympathetic
fight or flight
sympathetic
parasympatheticpreganglionic fibers are _____, while post ganglionic fibers are _______
LONG
short
what is the most important preganglionic parasympathetic nerve
VAGUS NERVE CN X
parasympathetic preganglionic fibers originate from the ____, ______ and ________
midbrain
medulla oblongata
sacral intumescence
preganglionic fibers of the PNS release ______
ACh
preganglionic neurons leave the spinal cord and terminate in _______
paravertebral chains
the only endogenous NT that stimulates the ANS and acts in both sympathetic and parasympathetic arms of the ANS
acetylcholine
the _____ chain allows for rapid, coordinated signal transmission through the entire sympathetic system
paravertebral
substance from adrenal gland that acts exclusively in the Sympathetic arm of the ANS
Adrenaline (Epi)
nicotinic receptors found in all ganglia of both the sympathetic and parasympathetic NS
Nn (nicotinic neuron) receptors in postsynaptic junctions and adrenal medulla
nicotinic receptors that are found in neuromuscular junctions of the somatic NS
Nm
nicotinic muscular receptors
where is the one place ACh has an effect on sympathetic tissue
sweat glands (except horses)
muscarinic receptors (M) are present in all _______ post-synaptic junctions
parasympathetic
Sympathetic innervation comes from _______ efferents
Thoracolumbar
sympathetic (thoracocolumbar) preganglionic fibers are ______ while post ganglionic sympathetics are _______
Short
Long
where are Nn cholinergic receptors found
Nn= nicotinic nerve
- ALLpostsynaptic ganglion junctions
- adrenal medulla
muscarine stimulates what receptors
Muscarainic (M) receptors
where are muscarinic (M) receptors found
in all parasympathetic post-synaptic junctions
heart, blood vessels, bronchioles, eye, bladder
AND
in sympathetic sweat gland (excpet in horses)
where are α1 adrenergic receptors found?
- vasculature
- GI
- urinary bladder
- spleen
- piloerector muscles
- male genitalia
where are α2 adrenergic receptors found?
- sympathetic pre-synaptic nerve terminals
- some endothelium
- platelets
- pancreatic islets
- kidney
where are adrenergic β1 receptors found?
- heart (stimulatory)
- GI tract
- urinary bladder
- kidney
- uterus
where are adrenergic β2 receptors found?
- bronchioles
- heart
- vasculature (skeletal blood vessels)
- liver
- pancreas
- fat cells
- sympathetic presynaptic nerve terminals
what is the only type of sympathetic receptor found in the bronchioles
β2
what are the endogenous NTs
- NE
- Epi
- Dopamine
where is NE released from
majority of post-ganglionic sympathetic nerves
EXCEPT sweat glands
what receptors does NE stimulate
α and some β1
where is epinephrine released from
adrenal medulla (in a mixture w/ NE)
where does epinephrine go and what does it act on / what receptors
- everywhere! (it’s a hormone)
- acts at nerve synapses or directly on vasculature
- stimulates α and β receptors
what receptors does dopamine activate
- vascular α (in high doses)
- cardiac β1 (inotropic) - mid doses
- DA receptors in renal and mesenteric vasculature - low doses
the resting tone of blood vessels (basal sympathetic tone) in controlled by ______ innervation
sympathetic
sympathetic stimulation of innervated receptors in vasculature smooth muscle maintains ?
blood pressure
basal sympathetic tone
is there normally any parasympathetic stimulation in the vasculature
no, therfore no active vasodilation
what type of M receptors are in the endothelium in vasculature
un-innervated M receptors
the response of vascular smooth muscle to sympathetic stimulation depends on ________
receptor distribution
in the skin and reservoir veins, what is the effect of sympathetic stimulation on vasculature
vasoconstriction (α1)
in skeletal muscle, what is the effect of sympathetic stimulation on vasculature
NE: vasoconstriction
Epinephrine:
vasoconstriction - if high levels of Epi (α1)
vasodilation - if low levels of Epi (β2)
what receptors in vasculature are more sensitive to epinephrine than α1 are?
β2
in visceral and renal vasculature, what is the effect of sympathetic stimulation (NE, Epi and DA)
NE: vasoconstriction
Epi: vasodilation if low levels, β2
Epi: vasoconstriction if high elvels, α1
DA: vasodilation of low levels via DA receptors, renal
DA: vasoconstriction if high levels of DA, α1
cardiac output is the result of ___ + _____
heart rate and Stroke volume
Mean arterial pressure is the result of what 3 things?
- peripheral vascular resistance
- cardiac output
- stroke volume
preload, afterload and contractility determine …
stroke volume
parasympathetic stimulation of the respiratory system causes…
bronchoconstriction and induces mucus secretion
what nerve innervates the respiratory system
vagus (M receptor)
what is the effect of sympathetic stimulation of the respiratory system
bronchodilation
β2 receptors
the facial nerve when stimulated by parasympathetics, stimulates _____ glands
salivary
what does the vagus nevrve innervate in the GI tract
- esophagus
- stomach
- pancreas
- liver
- smal intestines
effect of vagus nerve stimulation on GI tract
- relaxes sphincters
- stimulates GI motility
- stimuates gastric acid secretion
innervation of large intestines originates from the ______ and stimulates intestinal motility
lumbosacral intubescence
effects of sympathetics on the GI tract
- reduced salivary glands secretion
- reduced motility
- reduced acid secretion
- decreased secretion by pancreatic acinar cells
- increased secretions from islet cells (insulin)
- increased sphincter contraction
- increase glycogenolysis and gluconeogenesis by liver
- increases lipolysis
parasympathetic effects on genitourinary
- erection
- relaxes urinary sphincter
- induces contraction of urinary bladder fundus
sympathetic effects on genitourinary
- mediates uterine contraction cycle
- ejaculation
- increases renin secretion
- contracts urinary sphincter, relaxes fundus
parasympathetics effects on eye
- increases tear formation
- opens anterior chamber angle –> increases outflow of aqeous humor through the canal of schlemm and decreases IOP
what CN mediates parasympathetics to the eye
CN III oculomotor
sympathetics work on what receptors in the eye
α - contract radial muscles - mydriasis
alpha have no effect on accommodation
β - increaes aequous humor production causing increased IOP
β - relaxes ciliary muscles allowing for accomadation of nearby objects
sympathetics on the spleen
α - contraction
β2 -relaxation
piloerector muscles are mediated by ____ receptors and causes…?
α , contraction
what type of parasympathetic fibers are usually found within the innervated organ
short post ganglionics
what is the only endogenous NT that stimulates the cholinergic NS
ACh
Nn receptors in the adrenal medulla stimulate the release of ______ from _______
epinephrine from adrenals
