Lesson 1-4 Physio Ex

Question 1

What is the resting membrane potential of a neuron caused by?

Answer 1

the electrochemical gradient of ions Na+ and K+

Question 2

T/F: Alterations to the ion concentration inside or outside of the neuron will alter the resting membrane potential.

Answer 2

True

Question 3

Increasing extracellular [K+] causes the membrane potential to do what?

Answer 3

go from -70mV to -40mV

Question 4

increasing extracellular [Na+] causes the membrane potential to do what?

Answer 4

drop from -70mV to -72mV

Question 5

What is indicated by the greater change of the resting potential when [K+] is changed than when the [Na+] is changed?

Answer 5

there are more passive K+ channels than passive Na+ channels

Question 6

What maintains the difference in concentration of K+ and Na+ inside/outside the cell?

Answer 6

the Na+/K+ pump, without it the leak channels would eventually bring the potential to 0

Question 7

decreasing the extracellular [Na+] will cause what?

Answer 7

the membrane potential to become more negative since less Na+ will enter the cell via Na+ channels

Question 8

increasing the extracellular [K+] will cause what?

Answer 8

the membrane potential to become less negative since less K+ will leave the cell via passive K+ channels

Question 9

If the correct stimulus is applied to a sensory receptor will cause it to…

Answer 9

open or close membrane ion channels aka sensory transduction

Question 10

opening or closing ino channels with produce a _____ _____ that may be either depolarizing or hyperpolarizing

Answer 10

graded (local) potential

Question 11

What do Pacinian corpuscles respond to?

Answer 11

ranges of pressure

Question 12

What do Pacinian corpuscles NOT respond to?

Answer 12

chemicals, heat, or light stimuli

Question 13

Olfactory receptors respond to?

Answer 13

ranges of chemical stimulus

Question 14

What are olfactory receptors NOT responsive to?

Answer 14

pressure, heat, and light

Question 15

T/F: free nerve ending can respond to multiple modalities of stimuli

Answer 15

true

Question 16

What can free nerve endings respond to?

Answer 16

ranges of heat and pressure

Question 17

What is one reason free nerve endings can respond to multiple types of stimuli?

Answer 17

They are involved in detecting different types of excessive stimuli that will be perceived as pain

Question 18

a stimulus voltage of _____ and above elicited an action potential in the nerve

Answer 18

20mV

Question 19

Did increasing the voltage affect the speed or strength of the action potential?

Answer 19

no

Question 20

Why was there no decrease in the magnitude of the action potential between R1 and R2?

Answer 20

the action potential is regenerated at each segment of axon

Question 21

What triggers the depolarization of adjacent axon segments during action potential propagation?

Answer 21

an influx of Na+ into the axon triggers this

Question 22

why do action potentials only propagate in one direction?

Answer 22

because the regions of the membrane behind the action potential are in their absolute refractory period

Question 23

what are tetrodotoxin (TTX) and lidocain?

Answer 23

two nerve agents that disrupt nerve signaling by blocking Na+ channels

Question 24

TTX

Answer 24

a sodium channel antagonist; will permanently block Na+ channels preventing them from depolarizing

Question 25

Lidocaine

Answer 25

will not permanently block Na+ channels