Lab 7

Question 1

Generated by excitable cells, rapid reversal of polarity

Answer 1

Action potential

Question 2

Rising phase of action potential

Answer 2

Depolarization

Question 3

Falling phase of action potential

Answer 3

repolarization

Question 4

Undershoot of AP

Answer 4

Hyperpolarization

Question 5

Muscle cells of the heart, a phase of intermediate voltage precede the falling phase , extending duration of AP

Answer 5

Plateau phase

Question 6

Action potential is an —–

Answer 6

All or none process

Question 7

Specific information transmitted by the neurons encoded in the

Answer 7

Frequency of action potential and their velocity of conduction

Question 8

When there is no electrical activity

Cell difference across the cell membrane

Answer 8

Resting potential

Question 9

In resting potential is it negative inside or outside?

Answer 9

Negative inside

Question 10

Potential difference or the transmembrane potential in neurons at rest

Answer 10

-70mv

Question 11

These contributes to electrical activity of various cell bodies

Answer 11

Electrochemical pump, voltage gated channels Na, K leak channels , differential distribution of permeable and non permeable ions

Question 12

AP, of a nerve can be visualized on a computer screen through

Answer 12

Chart or scope software

Question 13

Which leg is dissected in frogs

Answer 13

Sciatic nerve

Question 14

Where does the nerve placed?

Answer 14

Nerve chamber

Question 15

Is a sciatic nerve compound or not

Answer 15

Compound nerve

Question 16

Thick myelinated fibers have ____ thresholds and conduct impulse ____

Answer 16

Lower , faster

Question 17

Unmyelinated or smaller diameter fibers which need strong stimulus

Answer 17

High threshold and slow conduction

Question 18

2 peaks

Answer 18

Compound action potential

Question 19

How does resolution increase?

Answer 19

Increasing the distance between the stimulating and recording electrodes and using sub maximal stimuli

Question 20

What does the increasing of distance significant for

Answer 20

Nerves has more time to pull away and separate from the action potential of slower conducting nerves

Question 21

Strength increase =

Answer 21

Current begins to excite larger areas of the axon

Question 22

Result of using sub maximal stimuli

Answer 22

AP occurs more quickly and the latency of stimulation decreases

Question 23

Voltage at which neuron is sufficiently stimulated (depolarizer) to fire action potential

Answer 23

Threshold

Question 24

At some stimulus voltage, all neurons reach threshold and fire all action potentials
Further increase will NOT recruit more axons to fire

Answer 24

Maximum response

Question 25

Strength of stimulus is____ as the duration of stimulus

Answer 25

Reverse proportional

Question 26

The minimal voltage over the longest duration of current flow milliseconds

Answer 26

Rheobase

Question 27

Significance of rheobase

Answer 27

Progressive increase in pulse duration is no longer associated with a progressive decrease in voltage

Question 28

The duration needed to produce a response at twice the rheobase strength

Answer 28

Chronoaxie

Question 29

Indicative of excitability of differ t nerves dependent of Na channels

Answer 29

Chronoaxie

Question 30

Significance of chronoaxie

Answer 30

If 2 nerves with the be same rheobase, chronoaxie the stimulus duration corresponding to twice the rheobase can give an indication of their relative excitabilities

Question 31

Equation of conduction velocity

Answer 31

cv = d/t (cm/s)

Question 32

Deflection caused by application of the voltage to the nerve

Answer 32

Stimulus artifact

Question 33

Often studied by measuring difference between the sites of 2 electrodes

Answer 33

Biolectrical phenomena

Question 34

Dropped on the nerve and increases the speed of conduction of AP

Answer 34

Warm ringers solution

Question 35

Decrease conduction velocity

Answer 35

Cold fingers solution

Question 36

Increasing the K+ ion concentration outside the axon will

Answer 36

Increase the rate at eh in potential will be generated or propagated

Question 37

Reason of KCl increase AP

Answer 37

Higher k+ concentration outside will prevent k efflux making inside more positive and closer to depolarization in shorter time

Question 38

Blocks voltage gated Na+ channels will inhibit propagation of AP

Answer 38

Lidocaine