Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CSF block 4 > Regulation of muscle > Flashcards

Regulation of muscle Flashcards

1
Q

describe the relationship between force of contraction and calcium concentration

A

increased calcium, increased contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what type of neurons regulate skeletal mm contraction?

A

motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a motor unit?

A

all of the individual myofibers innervated by the same motor unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what synthesized Ach is motor neurons?

A

choline + acteylCoA by choline acetyltransferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what packages Ach into vesicles?

A

vesicular ACh transporter (vACht)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what types of transporters are on the Ach vesicle membrane?

A

proton pump, ACh-H+ exchanger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what provides the energy for ACh to be pumped into vesicles?

A

H+ gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are “active zones”?

A

active zones are the linearly arranged ACh vesicles on the pre-synaptic neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe post-juctional folds

A

on the post- synaptic membrane of skeletal mm, clustered Ach receptors with voltage gated Na channels in the fold below

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the function of post-junctional folds

A

increase the surface area on the post-synaptic membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how do post junctional folds help to differentiate skeletal mm from other mm types?

A

because of the arrangement at the active zones and the post junctional fold, every releases of ACh will result in the generation of an AP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what lines the synaptic cleft in skeletal mm?

A

basal lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is contained in the basal lamina that lines the synaptic cleft in skeletal mm?

A

acetylcholinesterase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the post-synaptic receptor on skeletal mm cells?N

A

nicotinic ACh receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what ions can flow in the nicotinic ACh receptor?

A

Na+ in and K+ out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the net depol caused by ACh release in response to one AP in the motor neuron?

A

about 40 mV, which triggers action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what will the action potential activate in the T-tubules of skeletal mm?

A

DHP receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what happens once DHP receptors are activated?

A

DHP receptors have a physical interaction with RyR-1 receptors that triggers the release of Ca from sarcoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what removes Ca from cytosol in skeletal mm?

A

SERCA pumps and calsequestrin

20
Q

what is calsequestrin?

A

Ca binding protein in skeletal mm to reduce cytosolic Ca

21
Q

describe myasthenia gravis

A

myasthenia gravis is an autoimmune disease in which antibodies to the ACh receptors are made which causes mm weakness by decreasing transmission of the stimulus for contraction

22
Q

what are the MOA of botulinum toxin and tetanus toxin?

A

decrease ACh release

23
Q

what is the MOA od tubocaranine (poison dart)?

A

blocks ACh receptor channel

24
Q

differentiate between multi-unit and single unit smooth muscles

A

multi-unit allows for the control of individual mm cells and single unit allows for coordinated contraction of groups of smooth mm cells

25
Q

which type of smooth mm unit allows for fine mm movements?

A

multi-unit

26
Q

what is the source of Ca for skeletal mm contraction?

A

sarcoplasmic reticulum via RyR-1 receptors ONLY

27
Q

what is the sources of Ca for smooth mm contraction?

A

extracellular via voltage gated Ca channels and sarcoplasmic reticulum via IP3 receptors

28
Q

what is the neurotransmitter and receptor used for parasympathetic nerves in smooth mm?

A

Ach and muscarinic receptors

29
Q

what is the neurotransmitter and receptor used for sympathetic nerves in smooth mm?

A

norepinephrine and b-adrengergic receptors

30
Q

describe smooth mm stimulation by parasympathetic nerves

A

parasympathetic- generally promotes contraction of smooth mm (think rest and digest), release ACh that binds to muscarinic receptors, this stimulated Gaq, Gaq will stimulate phospholipase C that increases IP3 and DAG, IP3 will stimulate IP3 receptor on SER that triggers Ca release leading to contraction (through activation of MLCK)

31
Q

describe smooth mm stimulation by sympathetic nerves

A

norepinephrine binds to b-adrengeric receptor, activates GaS, this activates adenylyl cyclase resulting in increased cAMP, cAMP will inhibit MLCK, causing relaxation

32
Q

what synthesizes NO in endothelial cells?

A

eNOs

33
Q

what activated eNOs?

A

increased Ca concetration

34
Q

what is the action of NO in smooth mm?

A

synthesized by eNOs in endothelial cell
via paracrine signaling, travels into vascular smooth mm
NO activates guanylyl cyclase inside vascular smooth mm cell
guanylyl cyclase increases cGMP levels
cGMP stimulates MLCP which promotes relaxation

35
Q

describe the MOA of viagra

A

viagra is a phosphodiesterase inhibitor that increased cGMP levels, this activates MLCP and causes relaxation and erection

36
Q

do all smooth mm cells require external input to generate AP?

A

No!

37
Q

discuss Ca independent regulation of smooth mm contraction

A

via Rho-A kinase, when Rho-A kinase receptor is bound, it activates rho-A kinase, which phosphorylates serene/threonine on MLCP which inactivates it and promotes contraction

38
Q

which ion is MOST responsible for the upstroke of depol in smooth mm cells?

A

calcium is MOST responsible for the upstroke of depol because there are far more Ca channels than Na channels

39
Q

what are the pacemaker cells of the gut?

A

interstitial cells of canal

40
Q

what accounts for the “plateau” seen on membrane pot graphs of cardiac mm?

A

opening of Ca channels will balance K efflux, resulting in plateau

41
Q

what is the function of DHP receptors in cardiac mm?

A

voltage gated Ca channels

42
Q

describe the action of RYR-2 receptors

A

in cardiac mm, they are ca gated ca channels that allow for the release of Ca from SER

43
Q

what is phospholamban?

A

modulator of SERCA activity in cardiac mm

44
Q

what is the role of unphosphorylated-PLB?

A

inhibits SERCA pump to promote contraction

45
Q

what is the role of phosphorylated-PLB?

A

no inhibition of SERCA, allows SERCA to remove Ca from cytosol and promotes relaxation

CSF block 4 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions