Action Potential Propagation

Question 1

What is propagation?

Answer 1

The action potential is the movement of the action potential along the axon of the neuron.

Question 2

Propagation voltage-gated Na+ channels open and what?

Answer 2

They open in a section of the membrane, Na+ enters the cell then diffuses along the membrane. This causes depolarization of the adjacent section of the axon and opening of the next set of voltage-gated Na+ channels. This continues down the axon resulting in a wave of depolarization down its length.

Question 3

Where does the action potential move along?

Answer 3

The neuron too slowly to efficiently transmit information.

• Myelin insulates the axons of many neurons speeding up velocity of action potential propagation.
• Myelin = fatty

Question 4

What does wrap around?

Answer 4

axons

-Gaps are located within the myelin sheath down the length of the axon which is called Nodes of Ranvier

Question 5

What is the Nodes of Ranvier?

Answer 5

They contain high densities of Na+ and K+ channels

• The action potential skips or jumps from one Nodes of Ranvier to the next
• Salty conduction`

Question 6

The larger the axon diameter means?

Answer 6

The faster the transmission of the action potential.

Question 7

The thicker the myelin sheath means?

Answer 7

The faster the transmission of the action potential

unmyelinated neurons as having zero thickness of myelin

Question 8

Local anesthetics prevent?

Answer 8

Na+ channels from opening

Question 9

Fish toxins block what?

Answer 9

voltage gated Na+ channels from opening

Question 10

Hypokalemia is?

Answer 10

• Low K+ in the extracellular fluid

- May be due to use of diuretics

Question 11

Guillan-Barre is found in?

Answer 11

PNS

Question 12

Multiple Sclerosis is found in?

Answer 12

CNS

Question 13

What is Hansen’s Disease (Leprosy)

Answer 13

• Bacteria infects Schwann Cells
• Hands, feet, tip of nose, ears
• Loss of sensation - injury - tissue loss and deformity