musclees! Flashcards
(32 cards)
which neurotransmitter is typical at a neuromuscular junction? A acetylcholine B dopmine C acetylcholine esterase D glutamate E serotonin
OPTION A
an oldy but a goofy!
> option C is an enzyme (-ase)
which protein does calcium bind to on the thin filament to allow exctiation contraction coupling? A tropomyosin B troponin C actin D myosin E ATP
OPTION B
which relases tropomyosin alowing mysin head to bind
which receptors dihydropyridine receptor (DHPR) conformationally couple with to release calcium from SR? A voltage gated calcium channels B tropomyosin C ryanodine receptors D acetylcholine receptors E sarcolemma
OPTION C YEAH
> key word SR so this is just skeletal muscle
> key word also receptors
which length of striation spacing do skeltal muscle ususally function at A 200 micro m B 2cm C 2micro m D 3.5 cm E 1.5 micrro mete
2mircrometers
WHAT is the purpose of gap jucntion in cardiac muscle?
allow electrical activity between adjacent muscle fibres
allow physical spaces between adjacent muscle fibres
allow mechanical activity between adjacent muscle fibres
OPTION A
electricity yeaha
mechsnci al activty are more like physical barriers
does the SAN allow a slow or a fast response?
slow response!
which ion(s) influx during phase 0 of slow response cardic cells to cause depolarisation? calcium potassium sodum chloride
calcium and sodium!
'’the resting membrane potential of pacemaker cells in cardic muscle is unstabe’’
true of false?
turee
not flat
in cardicac muscle are the DHPR and ryanodine receptors conformationally coupled?
NO THY ARE NTOT
> come together to function but main source of calcium is extracellular instead of from ER
> Key word cardicac muscle (they ARE in skeletal muscle)
> calcium induced calcium signalling instead on ryanodine receptor
which of these is a function of smooth muscle
allow us run
pump blood around the body
move a bolus of food down oesphogus by peristalsis
ride a bike
OPTION C
name the presynaptic terminals that release neurotransmitter onto smooth muscle autonomic reflex varocisties presynaptic bulb acetylcholine
varicosities which are presynaptic terminals close to the effector cells
> presynaptic bulb forms part of the varicosity
where is calcium transpoted from to allow the contraction of smooth muscle? SR Extracellualr Fluid Intracellular Fluid ER
SR and ECF!
yaay
> SR as its just the muscle
which is true?
A skeletal muscle bigger than smooth muscle fibres
B smooth muscle cells are mutlinucleate
C skeletal muscle dont contrin sarcomeres
D cardiac muscle under autonomic control
E main calcium store for skeletal muscle is extracellualr
OPTION C
WHICH is false - relasted to cardiac muslce and fast repsonse cells
A reploarisation due to potassium eflux (phase 1)
B in fast reponse cells , phase 4 has a more negative resting membrane potential than baseline
C fast repsonse cells have stable resting membrane potential
D phase 0 due to sodium entry
E sinoatrial node is a type of fast reponse cells
OPTION E
- SAN is a Slow reposnse cell
which muscle(s) is striated?
sketletal and cardiac!
Which of the following is not a step in excitation contraction coupling in skeletal muscle?
Propagation of action potential into T-tubule
Activation of ryanodine receptor triggering conformational change in T-tubules and coupling with dihydropyridine
Release of Ca+ from sarcoplasmic reticulum
Binding of Ca+ to troponin causing conformational change in tropomyosin
Cross bridge formation and power stroke
OPTION B
DHP receptors on the T-tubule are activated
Ryanodine receptors on SR
what are T-tubules?
where the sarcolemma folds into the sarcoplasm! (like a crypt of lieberkuhns)
A cardiac cell that has a stable resting membrane potential and a phase 4 resting membrane potential that is more negative that it’s phase 0 resting potential is likely a..?
slow response cell
fast resposne cell
FAST REPONSE CELL
e.g. purkinjie fibre or Atria+Ventricles myocytes
> slow response cells have unstable resting membrane
which is the thick filament
actin or myosin?
myosin is thickk
in cardiac muscle what do the desomosomes and gap jucntion allow
> mechnincal jnctiion between adjacent fibres
> electrical connectivitity between adjacent fibres
where in cardiac cells is the action potential initiated A SAN B AVN C bundle of His D purkinjie fibres
SAN (the pacemaker cells) which have a slower resposne than cardiac cells
what causes the unstable resting memebrane potential in pacemaker cells?
funny channels which can open up below thereshold (hyperpolaried state) and Na+ can creep in
ture of false?
all muscles have both the absolute and relatvie refractory periods
FALSE
cardiac muscle only has the absolute = full hearbeats
> if not then there would be unsteady heartbeat/firbrilations
How is this done? sodium channels remain INACTIVE
what is tetanus?
the prolonged contraction of a muscle due to rapidly repated stimuli
