block 4 review deck

Question 1

what results from the stimulation of phospholipase C?

Answer 1

in Gaq pathway
stimulation of phospholipase C results in increased IP3 and DAG
results in contraction

Question 2

what is inhibited in striated mm at low calcium concentrations?

Answer 2

Pi dissociation is inhibited at low Ca concentrations

Question 3

what structural protein is ONLY found in skeletal mm?

Answer 3

nebulin

Question 4

what are the actions of caldesmon and calponin?

Answer 4

both participate in thin filament regulation in smooth mm, caldesmon (like TnT) and calponin (like TnI)

Question 5

familial hypertrophic cardiomyopathy

Answer 5

defect in myosin HEAVY chain

Question 6

when does “amplification” occur?

Answer 6

between signal reception and transduction

Question 7

what is the action of cAMP in smooth muscle

Answer 7

cAMP activates protein kinase A

protein kinase A phosphorylates MLCK to inactivate it and causes relaxation

Question 8

which G protein pathways are used in sympathetic vs. parasympathetic

Answer 8

parasympathetic- Gq - contraction

sympathetic- GaS- relaxation

Question 9

what does cGMP regulate?

Answer 9

neurotransmission and smooth mm contraction

Question 10

what does phospholamban regulate?

Answer 10

SERCA pumps
phosphorylated PLB- active SERCA
unphosphorylated PLB- inhibit SERCA

Question 11

what activates eNOs?

Answer 11

increased ca concentration

Question 12

what NT/receptor in Gq?

Answer 12

norepinephrine and a-adrenergic

Question 13

what NT/receptor in GaS?

Answer 13

epinephrine and b-adrenergic

Question 14

what NT/receptor in skeletal mm?

Answer 14

Ach and nicotinic receptors

Question 15

what NT and receptor in cardiac mm?

Answer 15

norepinephrine and b-adrenergic

Question 16

what is the action of protein kinase A?

Answer 16

activated by increased cAMP, promotes relaxation in smooth mm by inactivating MLCK

Question 17

what is the action of protein kinase C?

Answer 17

activated by increased DAG, promotes contraction in smooth mm cells

Question 18

what does elevated cAMP stimulate?

Answer 18

protein kinase a (relaxation)

Question 19

what does elevated cGMP stimulate?

Answer 19

MLCP (relaxation)

Question 20

what is a graded potential?

Answer 20

end plate potential thats amplitude will vary based on amount of neurotransmitter released

Question 21

what synthesize Ach?

Answer 21

choline acetyltransferases (CAT)

Question 22

why can skeletal mm cells generate AP with every release of ACh?

Answer 22

because of the arrangement of synaptic vesicles in active zones on pre-synaptic neuron and arrangement of post junctional folds in post-synaptic mm cells

Question 23

myasthenia gravis

Answer 23

autoimmune condition that destroys ACh receptors and will decrease end plate potential

Question 24

what is the effect of botulinum and tetanus toxins

Answer 24

decrease release of ACh from vesicles

Question 25

what is the effect of tubocarare?

Answer 25

inhibits ACh-receptors | will decrease end plate potential

Question 26

what are multi-unit vs. single unit smooth muscles?

Answer 26

multi-unit- more innervation for finer control | single unit- less innervation, coarse movements

Question 27

what is the parasympathetic NT and receptor?

Answer 27

ACh, muscarinic receptor

Question 28

what is the sympathetic NT and receptor?

Answer 28

norepinephrine and b-adrengeric receptor

Question 29

rho-A kinase

Answer 29

ca-independent stimulation of smooth mm contraction through inhibition of MLCP

Question 30

which ion is most responsible for the upstroke in smooth mm contraction?

Answer 30

Ca

Question 31

which ion is responsible for the plateau in cardiac mm action potential?

Answer 31

Ca

Question 32

what is the action of AChE?

Answer 32

deactivates ACh to prevent multiple reactivations of ACh receptors

Question 33

calmodulin

Answer 33

calcium binding protein that activates MLCK and promotes contraction of smooth mm

Question 34

mechanism underlying steroid hormone action

Answer 34

depends upon specific intracellular receptor that, in turn, binds to DNA and affects transcription

Question 35

diphtheria toxin

Answer 35

inactivates the inhibitor of adenylyl cyclase to increase cAMP levels, which will promote relaxation of smooth mm and also affect protein synthesis

Question 36

what is the "power stroke" in mm contraction

Answer 36

dissociation of Pi from actomyosin-ADP-Pi

Question 37

what type of filaments are associated with desmosomes?

Answer 37

intermediate filaments

Question 38

what is the effect of increasing nerve impulses to a single skeletal mm motor unit?

Answer 38

will increase the tension of the mm fibers so long as Ach is released

Question 39

what is the length constant and what affects it?

Answer 39

length constant is how far the end plate potential is propagated, directly proportional to axon width and membrane resistance

Question 40

what is the effect of myelination on the length constant

Answer 40

myelin increases resistance of the membrane and increases the length constant

Question 41

what is the effect of axon width on the length constant

Answer 41

wider axon, increased length constant

Question 42

EPSP

Answer 42

excitatory (+) in or (-) out leads to depolarization

Question 43

IPSP

Answer 43

inhibitory (+) out or (-) in leads to hyper polarization

Question 44

what is multi-unit smooth mm composed of?

Answer 44

smooth mm cells that are NOT electrically coupled

Question 45

what type of mm exhibits slow wave changes in electrical and mechanical activity?

Answer 45

smooth mm

Question 46

what could be used to treat myasthenia gravis?

Answer 46

K channel blockers to prolong depol and increase the ACh present in synapse

Question 47

what accounts for the increased resting-length tension of cardiac mm compared to skeletal mm?

Answer 47

titin is shorter in cardiac mm than skeletal mm

Question 48

what occurs during striated mm contraction?

Answer 48

thick and thin filaments slide past each other

Question 49

what is the effect of increased calcium on force of contraction?

Answer 49

increase Ca, increase force of contraction

Question 50

why does an end plate potential occur?

Answer 50

because Na permeability becomes greater than K permeability

Question 51

what are the 2 proteins found on the membranes of NT vesicles in motor neurons?

Answer 51

H+/Ach exchanger (secondary AT) | H+ ATPase (primary ATP)

Question 52

which 2 substances provide passive-length tension in striated mm?

Answer 52

collagen and titin

Question 53

which protein is found on z-disc and dense bodies?

Answer 53

a-actinin

Question 54

what is active force proportional to?

Answer 54

the number of active cross bridges

Question 55

sequence for transmission of force from contractile proteins to extracellular space in cardiac mm

Answer 55

``` motor proteins z-line proteins cytoskeletal actin focal contact proteins connector proteins extracellular matrix proteins ```

Question 56

what stabilizes actin in skeletal mm and is not found in smooth or cardiac mm?

Answer 56

nebulin

Question 57

why can smooth mm produce greater active force than cardiac mm?

Answer 57

side-polar arrangement of actiomyosin cross bridges

Question 58

what is the major components of the z-line?

Answer 58

a-actinin

Question 59

what is permitted when Ca binds to the thin filament in striated mm?

Answer 59

binding of Ca allows for phosphate to dissociate from actomyosin-ADP-Pi ca also changes the position of tropomyosin to expose myosin binding sites on actin

Question 60

what forms latch bridges in smooth mm?

Answer 60

thought to be due to the slow rate of ADP dissociation from cross bridges after the power stroke

Question 61

spatial summation

Answer 61

summation of EPSPs from many presynaptic sources

Question 62

temporal summation

Answer 62

summation of EPSPs from one presynaptic source

Question 63

which type of skeletal mm is most fatiguable?

Answer 63

fast twitch type IIB/IIX