Lecture 6

Question 1

Where is Na+ concentration the highest?

Answer 1

In the extracellular

Question 2

Where is K+ concentration the highest?

Answer 2

In the intracellular

Question 3

Where is Ca2+ concentration the highest?

Answer 3

In the extracellular

Question 4

Where is the Cl- concentration the highest?

Answer 4

In the extracellular

Question 5

What is Resting Membrane Potential?

Answer 5

Electrical charge separation across a membrane…at REST

Question 6

What does a neuron do at Resting Potential?

Answer 6

Not triggered to release a neurotransmitter

Question 7

What does a muscle cell do at Resting Potential?

Answer 7

Not triggered to produce a force

Question 8

What is the mV of RMP

Answer 8

-80 to -60mV (depends on the cell)
- Cytosol vs.Extracellular Fluid

Question 9

What does the resting membrane potential being negative mean?

Answer 9

It is in a “polarized state” - negative inside

Question 10

What is Depolarization?

Answer 10

It loses polarity (switches to positive inside)
- Doing this by adding positively charged elements to the inside (Na+)

Question 11

What is repolarization?

Answer 11

Restoring the polarized state (resting)

Question 12

What is Hyperpolarization?

Answer 12

Making the cell “more” polarized.

Question 13

What are the two types of biological signalling?

Answer 13

Electrical and chemical

Question 14

What is the NERNST equation?

Answer 14

A measure of the equilibrium potential for ion, S

Question 15

What is EN?

Answer 15

The voltage difference across a membrane to hold that ion in equilibrium.

Question 16

What is the ENa?

Answer 16

+67mV

Question 17

What is the Ek?

Answer 17

-98mV

Question 18

What does the ENa and Ek values mean?

Answer 18

To hold sodium in equilibrium concentrations (145mM outside and 12mM inside), need a voltage difference of +67mV on the INSIDE of the cell.

Question 19

What is a key concept?

Answer 19

Opposite charges attract, like charges repel (polarity)

Question 20

What is the effect of a positive voltage inside the cell on Na+?

Answer 20

Has a repelling effect (keeps it outside the cell)

Question 21

What is the effect of a negative voltage inside the cell on K+?

Answer 21

Has an attractive effect (keep it inside the cell)

Question 22

What is the RMP for a skeletal muscle cell?

Answer 22

-65mV.

Question 23

What is Potassium considered to be?

Answer 23

A negative ion at -75mV
(Why the inside of the cell is considered to be electronegative at RMP)

Question 24

What is Sodium considered to be?

Answer 24

A positive ion at 55mV
(Why when the cell gets depolarized and sodium floods in, the cell turns positive)

Question 25

Depolarizing Potential

Answer 25

Moves membrane towards threshold

Question 26

Hyperpolarizing Threshold

Answer 26

Moving membrane away from the threshold

Question 27

What is a Temporal Summation?

Answer 27

Increased frequency of stimulations from ONE NEURON

Question 28

What is Spatial Summation?

Answer 28

Increased frequency of stimulations from MULTIPLE NEURONS