Exam 3 Flashcards
autonomic nervous system
two branches- sympathetic and parasympathetic
involuntary control of organ function
organ contraction, HR/BP, stress response
ANS in relation to daily acitivity
sympathetic branch- associated with stress and physical activity, mental/emotional stress, exercise
parasympathetic- associated with rest and “slow” background activity, increased digestion, lower overall activity
ANS neuron configuration
2 neuron series- preganglionic neuron and postganglionic neuron
where is the cell body in a preganglionic neuron
cell body located within CNS
where is the cell body of a postganglionic neuron
cell body is located within autonomic ganglia
sympathetic: sympathetic chain ganglia parasympathetic: terminal ganglia, near or on surface of effector
2 neuron series sympathetic
start in spinal cord
preganglionic neuron goes to postganglionic neuron in sympathetic chain ganglia
postganglionic neuron goes to
effector
2 neuron series parasympathetic
start in brain stem
preganglionic neuron goes way down to postganglionic neuron at terminal ganglia
postganglionic neuron goes to effector
where are NTs released in 2 neuron series
at preganglionic to postganglionic and at postganglionic to effector
autonomic neurons and their NTs
different autonomic neurons secrete different NTs
neuron type based on the type of NT that is released
types of NTs released
cholinergic neuron
adrenergic neruon
cholinergic neuron releases
acetylcholine
adrenergic neuron releases
norepinehprine
receptors for specific NTs
cholinergic
adrengeric
cholinergic receptor
binds acetylcholine
2 types of cholinergic receptors
muscarinic
nicotinic
nicotinic receptor
on postganglionic neuron
both sympathetic and parasympathetic
muscarinic receptor
on surface of effector, mainly in parasympathetic
adrenergic receptor
binds norepinephrine and epinephrine
2 types of adrenergic receptors
alpha adrenergic receptor
beta adrenergic receptor
alpha adrenergic receptor
responds more to norepinephrine than epinephrine
beta adrenergic receptor
respond equally to norepinephrine and epinephrine
preganglionic neurons: NTs effects
preganglionic NTs secreted affects postganglionic neuron
in both sympathetic and parasympathetic
secretes acetylcholine
postganglionic neurons: NTs and effects
postganglionic NTs affect effector organs
in parasympathetic- cholinergic neurons- secrete acetylcholine in response to preganglionic stimulation
in sympathetic- adrenergic neurons- secrete norepinephrine in response to preganglionic stimulation
sympathetic prgn and pgn pathway
Prgn- cholinergic neuron secretes Ach binds to nicotinic receptor on pgn- adrenergic neuron secretes norepinephrine binds to alpha or beta adrenergic receptors on effector
parasympathetic prgn and pgn pathway
prgn- cholinergic neuron secretes Ach binds to nicotinic receptor on pgn- cholinergic neurons secretes Ach binds to muscarinic receptor on effector
regulation of ANS responses
many effector organs have input from sym and psym divisions
1 antagonistic effects
2 coordinated response
antagonistic effects
sympathetic and parasympathetic produce opposite effects
one may have a stronger effect than the other
coordinated response
1 one division can coordinate activity of multiple different structures
2 both divisions can coordinate activity of different structures for the same purpose
eyes sympathetic vs parasympathetic
sympathetic- pupil dilation
parasympathetic- pupil constriction
Bronchi sympathetic vs parasympathetic
sympathetic- bronchodilation
parasympathetic- bronchoconstriction
GI tract sympathetic vs parasympathetic
sympathetic- decrease digestion
parasympathetic- increase digestion
heart sympathetic vs parasympathetic
sympathetic- increase HR, BP, force of contraction
parasympathetic- decrease HR, BP, force of contraction
blood vessels sympathetic vs parasympathetic
sympathetic- mostly vasoconstriction (alpha adrenergic receptors), increase BP, some vasodilation (beta adrenergic receptors)
parasympathetic- vasodilation of some blood vessels, very little effect on systemic BP
response to stress
mass activity of sympathetic division- activates adaptations to escape stressor
increase BG, HR, blood flow to muscles, respiratory rate, inhibition of non-essential activities (digestion, reproduction)
fast acting response
system (whole body) effects
more noticeable with sympathetic stimulation
some preganglionic sympathetic neurons stimulate adrenal medulla
Ach goes to adrenal medulla, adrenal medulla secretes epinephrine, epinephrine enters circulation and affects functions of other organs
pharmacology
receptor agonists
receptor antagonists
receptor agonists
drugs that bind to receptor and mimics effects of endogenous NTs
sympathomimetic drugs
parasympathomimetic drugs
receptor antagonists
drugs that bind to receptor and block effect of endogenous NTs
innervation of vasculature
nervous stimulation- motor neurons
blood vessels- capillary beds around muscle fibers, supplied and drained by arteries and veins
delivery of oxygen rich blood
muscle fibers
composed of many myofibrils
myofibrils
composed of actin myofilaments (thin filament) and myosin myofilaments (thick filament), titan
sarcolemma
plasma membrane of muslce fiber
sarcoplasma
cytoplasm of muscle fiber
sarcomere
made up of action and myosin joined end to end
what is the smallest contractile structure
sarcomere
a band
length of myosin, some overlapping of myosin and actin
i band
contain actin and z disk
actin structure
F actin- 2 strands in a helix
G actin- has an active site for binding myosin heads
troponin
tropomyosin
troponin
3 subunits, 1 binds to g- actin, 1 binds to tropomyosin, 1 has binding site for Ca++
tropomyosin
sits within indention of helix
at rest- blocks active sites of g- actin
myosin
2 myosin heavy chains forming a rod
hinge region- allows bending of myosin heads
myosin heads- capable of binding to g-actin
4 myosin light chains- attached to myosin heads, regulatory function
myosin heads
cross bridge formation
binding of myosin head and actin molecule
facilitates contraction of muscle- hinge region, bending and straightening
heads have ATPase that does ATP hydrolysis that releases energy for bending of hinge
sliding filament model
actin myofilament sliding over the myosin myofilament shortening of sarcomere this translates to muscle contraction
sliding filament model
relaxation
lengthening of sarcomere
external forces- contraction of antagonist muscle or gravity
neuromuscular junction/ motor end plate
synapse of motor neuron on muscle fiber
Ach secretion by motor neuron
Ach binds to ligand gated ion channels on muscle fiber
Na+ rushes into muscle, depolarization of muscle fiber
excitation- contraction coupling
conversion of neural signals into physical process of contraction t-tubles sarcoplasmic reticulum (SR)
steps to muscle contraction
neuron action potential- muscle action potential- contraction
t-tubules
transverse tubules
infoldings of sarcolema