Electrophysiology 100 set wrong answers

Question 1

5. low plasma

Answer 1

cellular RMP would be hyperpolarized from normal value

Question 2

9. an increased duration of the axonal AP can be caused by

Answer 2

a blockcade of INACTIVATION of the VG sodium channels

Question 3

21. tenany mechanism: greater tension can be measured from Skel. musc. during tentany compared to twitch bc

Answer 3

the number of cross bridges formed can increase per cycle

Question 4

if you increase the length of a resting SkelMusc. to twice its normal length and then stimulate it to produce a max isometric contraction you’ll find that

Answer 4

the number of cross bridges formed will be unchanged at the new length

Question 5

high plasma Ca

Answer 5

less excitability, the amount of current needed to initiate an axonal AP is higher than normal, due to shielding; due to shielding effect

Question 6

high calcium AP looks like what

Answer 6

higher to threshold, threshold is more positive, (‘lower’)

Question 7

38 help. how to define an unknown non ionic substance moving into a cell is simple diffusion

Answer 7

the relationship between flux of x and the concentration in the outside medium is linear over all concentrations, facilitated diffusion must be non linear in some way because it relies on voltage, ligand, etc

Question 8

which ionic channel WOULD in hypothetical land produce the greatest amount of membrane depolarization when opened by an NT

Answer 8

a channel specifically permeable to calcium because Ca gradient is higher and because the charge is larger the flow of Ca will be larger= more depolarization3w

Question 9

which ionic channel WOULD in hypothetical land produce the greatest amount of membrane depolarization when opened by an NT

Answer 9

a channel specifically permeable to calcium because Ca gradient is higher and because the charge is larger the flow of Ca will be larger= more depolarization3w

Question 10

a typical excitatory end plate potential

Answer 10

is terminated by the removal of NT

Question 11

voltage sensor on T tubule membrane of skeletal muscle

Answer 11

senses depolarization of the T tubule, initiates the opening of Ca chanels on teh SR membrane, its action is associated with the fast release phase for Ca, inhibited by DHP

Question 12

channel vs transporter/ carrier

Answer 12

a carrier is not simultaneously open to both IC and EC space- only 1 gate is opened at a time, - millions of ions can pass through a channel, but very few can pass through a carrier like 1 or a few

Question 13

70. help L type VG and calcium alteration??

Answer 13

alteration of the EC Ca alters the reverse potential of the current as predicted by the Nernst equation

Question 14

78. calcium activated calcium

Answer 14

it occurs via a direct action of Ca on the DHP Voltage sensor of the T tubule

Question 15

79. in myotonic dystrophy skeletal muscle is unable to fully relax after contraction

Answer 15

decreased INACTIVATION of VG sodium channels located on the membrane

Question 16

the primary characterisitc of sustained tonic contraction of smooth muscle is

Answer 16

low ATP use

Question 17

96. max tension is developed at the point of the graph:

Answer 17

highest point, highest y value

Question 18

97. no overlap of thick and thin filaments

Answer 18

most righward

Question 19

98. an experiment is performed in which the myosin backbone protein is mutated to prevent hinge of crosss bridge

Answer 19

shortening off I band would be blocked