Lectures 13-15

Question 1

What are ions responsible for (2)

Answer 1

Responsible for moving ions in an out of cell to make action potential happen

responsible for difference in charge across neural membrane

Question 2

What are atoms made of and what 3 things does it contain (PEN)

Answer 2

Made of subotomic particles

Protons
Electrons
Neurons

Question 3

What charges are Protons, neurons and electrons

Answer 3

Protons are positive
electrons are negative
neurons are uncharged in this case

Question 4

What state allows action potentials to occur? Hint: scale, balance

Answer 4

When there is more positive charge inside a neuron, more negative charge outside of neuron

This state of imbalance is what allows action potential to occur

Question 5

What do volts measure?

Answer 5

Measure electrical potential

Question 6

What’s the typical volt charge in humans ?

Answer 6

70 milivolts (mv)

Question 7

What is membrane permeability and what how is it produced ?

Answer 7

Things that can/t permeate by ion channels

Produced by proteins

Question 8

what’s 2 forces drive ion to move in or out of cell?

Answer 8

1 concentration gradient force
2 electrical gradient force

Question 9

What is an ion(definition) Hint: Balance

Answer 9

Atoms that have imbalanced electrical charges

Question 10

What are the two types of ions and their charges?

Answer 10

Anion- negatively charged
Cation-positively charged

Question 11

What kind of molecule is water, and what makes it this way?

Answer 11

Polar molecule, one side has more negative charge, other side has more positive charge

Question 12

What are cations and anions attracted to?

Answer 12

Anions are more attracted to positive end
Cations are more attracted to negative ends (opposites attract)

Question 13

What is the cell membrane made up of?

Answer 13

Fatty substance, 2 fatty acids back to back create a cell membrane

Question 14

What are the Cell membranes permeable (1) and non permeable chemicals (2)? (Remember BBB permeables)

Answer 14

Small lipid soluble molecules
can permeate

Large or electrically charged molecules cannot permeate

Question 15

How do ions move in and out of cell, and what product created it?

Answer 15

By ion channels(holes) created by proteins

Question 16

What is gating and what are two main factors that influence it?

Answer 16

Channels that change shape(open or closed)

Two factors:
Voltage dependent
Chemical dependent

Question 17

what does voltage dependent mean?

Answer 17

Opens or closes gate depending on what surround membrane potential is

Question 18

what does chemical dependent mean?

Answer 18

Chemical is presented and gate decides whether or not it will stay closed or open up,

Question 19

What are the three ways ions are able to permeate the Cell membrane? (Ch,Ch,S)

Answer 19

1) Through Channels: only allow particular ions to move through

2) Chemical dependent: By being a certain chemical

3) Surroundings: Able to permeate based off of what’s already in the membrane

Question 20

What are the two forces that drive ion movement?

Answer 20

1) concentration gradient force
2) electrical gradient force

Question 21

What is the concentration Gradient force? ( think of drop of food dye in glass of water…)

Answer 21

Random motion of matter, chemicals move down the gradient trying to become equally separated . Tries to move to lower area of concentration essentially.

Question 22

What is electrical gradient force? (the long triangle!!)

Answer 22

Positive and negative charges that are attracted to one another, BUT are repelled by the like charge. (positive charge loves negative charge, but is repped by positive charge )

Question 23

Why’s there a difference of charge within the membrane potential, and what are they? (4) HINT: banana in the ocean…

Answer 23

Due to 4 ions
Na-sodium
Cl-chloride
K-potassium
Proteins

Question 24

The 4 ions impacting a difference in charge in the membrane potential,
are found where in higher concentration in a neuron ?

Answer 24

Na and Cl are found in higher concentration outside neuron

K and proteins are found in higher concentration inside neuron

Question 25

4 factors influencing movement in the membrane (SECS)

Answer 25

Selective permeability
electrical gradient force
Chemical gradient force
sodium potassium pump

Question 26

What are the 4 changes you can see in membrane potential ?

Answer 26

Hyperpolarization
depolarization
resting potential
action potential

Question 27

What is the difference between sub threshold de polarization and a supra threshold (opposites)

Answer 27

Sub threshold: not enough threshold to conduct an action potential

Supra threshold: big enough de polarizations to still conduct an action potential

Question 28

What is an Action potential ?

Answer 28

rapid reversible self propagating change in membrane potential

Question 29

What are the 3 phases of an action potential?

Answer 29

Rising phase
Peak and falling phase
After hyperpolarization

Question 30

What happens in the rising phase of an action potential?

Answer 30

Membrane continues to depolarize,

sodium and Potassium
channels open and sodium rushes in

Becomes more positively charged

Question 31

What happens in the peak and falling phase of an action potential?

Answer 31

Peaks out, while potassium channels still open, leaks out potassium

voltage sensitive sodium channels inactivate(change shape and close).

Becomes more negatively charged overall

Question 32

What happens in the after hyper polarization phase of an action potential?

Answer 32

Gets even more negatively charged as excessive potassium leaves
Overshoots and returns back to resting membrane potential to rinse and repeat cycle

Question 33

What are the three steps to how propogation happens?

Answer 33

1) sodium diffuses causing supra threshold
2) depolarization opens voltage gated sodium channels
3) triggers Action potential in adjacent(near) regions

Question 34

Why do action potentials only move in a forward region?

Answer 34

The inactivating property of sodium channels (during 4 changes in membrane potential) propagate to move things only forward