Muscles And Syanpses L4

Question 1

AP transmission

Answer 1

1) Axon at resting memb. Pot.
2) activation results in opening of voltage Na+ channels, local depol. Of the memb.
3) local depol. Of memb. Causes adjacent voltage gated Na+ channels to open
4) new AP generated in adjacent memb.

Question 2

AP only travels in

Answer 2

1 directions due to refractory period (electronic condition)

Question 3

Electronic conduction

Answer 3

Spread of current inside axon

how AP travels down axon

Question 4

Electronic current flow is fast, but must be regenerated at every point on the memb., this would take to long, so how is this sped up?

Answer 4

Myelination

Question 5

Myelination

Answer 5

• increases speed of EC
• Schwann cells in PNS
• obligendrocyes in CNS

Question 6

Myelination is continuous or discontinuous

Answer 6

Discontinuous = nodes of ranvier

Question 7

Many Schwann cells unsheathe

Answer 7

1 axon in the PNS

Question 8

One oligodendrocyte ensheaths

Answer 8

many axons in the CNS

Question 9

Saltatory conduction

Answer 9

AP being regenerated at the nodes of ranvier, but current flows electronically through nodes

Question 10

Myelination increase speed of conduction by increasing efficiency of electronic conduction such that

Answer 10

AP doesn’t need to regenerate at every point of the axon

Question 11

Classification of afferent fibre types

Answer 11

4 types,

Type 1 being thicker myelination = fastest
(Skeletal muscle propiocepter)

Type 2 = skin receptor

Type 3= pain and temp

Type 4 being thinner myelination = slowest
(Pain/itch/temp)