Physiology

Question 1

Resting Membrane Potential

Answer 1

A charged difference that sits, waiting to be excited

e.g. muscles contract, neurons send signals (around -70mV)

Question 2

Sodium

Answer 2

Most of it out of the cell

Question 3

Potassium

Answer 3

Most of it inside the cell

Question 4

Sodium-Potassium ATPase pump

Answer 4

With the use of ATP:
Takes 3 sodium outside
2 potasium inside
Making the inside more negatively charged (-5mV)

Question 5

Potassium Channels

Answer 5

Allow some additional potassium to leak outside of the cell, making the inside even more negatively charged

Question 6

Action Potential

Answer 6

Any time a cell sends a signal it does it via action potential. Ions moving in or out of a neuron

Question 7

Neurotransmitters

Answer 7

Bind to receptors- they excite the neuron into action

e.g.: glutamate binding to glutamate receptors

Question 8

Threshold Potential

Answer 8

The potential at which the voltage-gated channels begin to open and allow sodium into the cell (like a domino effect). -55mV

Question 9

Hyperpolarization

Answer 9

After potassium voltage-gated channels allow potassium to leave the cell, so much potassium leaves the cell that the charge inside goes down to -90mV. Inhibiting the cell from firing again.

Question 10

Depolarization

Answer 10

Upon receiving signal from neurotransmitter, the voltge-gated channels allow sodium into the cell, making the inside of the cell positive. (+30mV)

Question 11

Repolarization

Answer 11

Upon reaching +30mV potential, sodium voltage-gated channels close, potassium voltage-gated channels open and allow potassium out of the cell making the potential inside of the cell more and more negative

Question 12

Myelin

Answer 12

Prevents depolarization a sites where it surrounds the axons

Question 13

Node of Ranvier

Answer 13

Segments of the axon that are not covered with myelin. Depolarization can occur