module 9

Question 1

Where does the action potential start in a neuron?

Answer 1

In the initial segment of the neuron. This is the first part of the axon.

Question 2

What does the action potential do?

Answer 2

Once it reaches the axon terminals it causes the release of neurotransmitters onto the postsynaptic cell.

Question 3

Oligodendrocytes/Schwann Cells

Answer 3

Synthesize myelin sheath for the axon

Question 4

Astrocytes

Answer 4

Found wrapped around the capillaries in the brain; provide extra protection from the contents in the brain.

Question 5

Draw a neuron include all parts

Answer 5

1. Dendrite
2. Cell body(cell body)
3. Axon hillock
4. Initial segment
5. Axon with myelin
6. Axon terminal with terminal boutons

Question 6

What is the equilibrium force denoted E?

Answer 6

The equilibrium force occurs when the electrical and chemical driving forces are equal and opposite and the ion is at equilibrium. Ions are always striving towards this. No net movement occurs at this stage but individual movement may occur.

Question 7

Leak ion channels

Answer 7

These are channels that are always open in the membrane.

Question 8

What kind of channels would move Na+ and K+?

Answer 8

Ion channels via facilitated diffusion.

Question 9

Chemical (concentration force)

Answer 9

Drives the ions from high to low concentrations

Question 10

Electrical Force

Answer 10

The ion movement depends on the voltage membrane (inside charge) of the cell. Opposites attract!

Question 11

Why is the resting Vm negative?

Answer 11

1. Membrane is more permeable to K+ which is constantly leaving the cell to move the equilibrium to -90mV. Na+ some channels are open causing the slightly more positive charge of -70 mV.
2. Proteins inside are negatively charged.
3. Na/K ATPase pump which has a net positive charge of 3 going out of the cell via Na+ and only pumps in two K+.