MA - Nervous System II

Question 1

What is an action potential?

Answer 1

A brief change in electrical potential across the cell’s membrane involving the movement of ions (Na+ and K+) across the membrane – in response to stimulation

Question 2

What acts to mantain the concentration gradient?

Answer 2

Ionic pumps

Question 3

Why can a membrane not be excited after an action potential?

Answer 3

There is a refractory period

Question 4

What are capacitors?

Answer 4

They store electrical charge

Question 5

What is an example of a biological capacitor?

Answer 5

Lipid Membrane

Question 6

Why are only a few ions required to move to generate an action potential?

Answer 6

Lipid membrane is a capacitor

Question 7

What 3 properties of neurons allow for rapid conduction of signals?

Answer 7

1. Positive feedback of voltage gated channels to allow for rapid depolarisation
2. Propagation of voltage change over the membrane surface
3. Myelination results in increased conduction velocity

Question 8

What are 2 ways the Myelin Sheath is formed?

Answer 8

1. Formed by Schwann cells in peripheral nerves
2. Formed by oligodendrocytes in CNS

Question 9

What occurs after recognition of the neurotransmitter on the post-synaptic membrane?

Answer 9

The neurotransmitter must be inactivated
* So they do not continually occupy postsynaptic receptor sites