ANS & muscle Flashcards
neurochemical simlarity & difference btw PSNS & SNS
(+): release ACh at ganglions
(-): @ postganglion neurons, PSNS release ACh it at muscarinic receptor while SNS release norepinephrine to a receptor
ANS VS somatic nervous system: anatomy & neurochemical signailing
ANS requires post- and pre- gangionic neurons. SNS ALSO requires 2 neurons.
but motor neuron synpse to muscle cell
unique abt ANS control of adrenal gland?
only 1 SNS preganionic neuron to adrenal gland, which secretes epinephrine w/ lil NE
whole muscle is made up of _____ contains bundle of _____ which is composed of a bundle of _____
fascicle / muscle cell / myofibrils
sarcoplasmic reticulus wraps around _____ and is where ___ is stored
myofibril / Ca
____ travels down interior of muscle cell and wrap around each _____; allow ___ to travel from surface down inside muscle cell
transverse tubules / myofibril / AP
troponin C binds to ___ / T to____/ A to ___
calcium / tropomyosin / actin
what is a power stroke?
when myosin head undergoes conformational change to generate contraction
what is sliding filament theory?
myosin head binds to G-actin
when sacomere contracts, myosin head undergoes a power stroke (push) -> thin myofilament slides over the thick -> sacomere contracts, muscle contractwsw
describes what happened in Excitation Contraction Coupling in skeletal muscle?
AP from NMJ propagtes from sarcolemma to T-tubule cell
voltage sensor senses AP and changes shape
..opens the Ca++ channel and releases Ca
Ca tore the tropomyosin away from myosin binding site
sliding filemtn theory occurs
nyscle contracts
cause of rigor mortis?
no O -> no ATP
=> Ca+ cant be pumped back into SR
actin and myosin can’t dissoiciate
muscle permenatly fused until began decon
how to increase force of contraction?
more motor unit recruitment
=> more muscle fibers contract whcih increase contractile force
summation of twitch contractio: increased stimulus frequency
contrast how ANS vs somatic nervous system is controlled
ANS: regulation centre compares these signals and activates the hypothalamus (master controller of ANS) -> outputs to SNS & PSNS -> innervate smooth and cardiac muscle
s.m.s: activates the motor cortex -> output to alpha and gamma motor neurons -> innercates skeletal muscle
CONTRAST the effects of PSNS vs SNS
PSNS:
- less light enters the eye
- decreases heart rate
- increases digestion and absorption of nutr
- contracts bladder
SNS:
- more light enters eye
- increases heart rate
- shuts down digestion
- holds urine
describe the thin myofilament?
contains G-actin: form an alpha-helical chain. each has a myosin binding site
tropomyosin: cover the myosin binding site
and troponin
what needs to happen for muscle to relax?
Ca2+ needs tb actively pumped back into SR via Ca ATPase against the concentration gradient
when that happens, tropomyosin cover the myosin binding site again
Z-line holds _____ myofilement while M-line holds ____ myofilament
thin / thick
what happens in summation of twitch contraction?
muscle twitch has less time to relax before another one comes
stack up each other -> to increase contraction
contrast unfused tetanus vs complete tetanus
high frequency AP vs very high frequency AP
has time to relax vs no relaxation at all
vs all twitches summate to produce a smooth, sustained contraction
contrast skeletal muscle vs smooth muscle
Skeletal:
voluntary
striated, multinucleated
sticks to skeleton
Smooth muscle:
unvoluntary
nonstriatd, spindle-shaped, and uninucleated
Covers of internal cell wall
caveola
smooth muscle has ___ potential and ___ potential, which is alternating hyperpol & ____ due to changes in the ___ permeability.
when threshold reach, trigger ____ & _____
pacemaker / slowave / depol / Na+
AP / muscle contract
ECC in smooth muscle?
Ca+ from ECF binds to calmodulin
activates kinase to phosphorylate myosin
cross bridge formation and power stroke
muscle contracts: filament slide past e/o + pull on dense bodies
