action potential velocity and electrical signals

Question 1

describe how action potentials effect electrical signals

Answer 1

action potentials allow electrical signals to be conducted over large distances without decaying

Question 2

describe what is meant when its said that the nerve cell membrane is ‘leaky’ and the effect this has on passive signals

Answer 2

‘leaky’ = not a perfect/very good insulator

results in passive signals not spreading far from their origin

Question 3

what is passive conduction a factor in

Answer 3

reproduction of the action potential(AP)

Question 4

describe the relationship between the ‘leaky’ nerve cell membrane and AP conduction velocity

Answer 4

the less ‘leaky’ the cell membrane the greater the local current spread, and the greater the local current speed the greater the AP conduction velocity

Question 5

describe ways in which the passive conduction speed can be increased

Answer 5

increased axon diameter

decreasing the leak of current across the axon by using an insulating cover, such as the myelin sheath

Question 6

state what different cell types make up the myelin in the different nevrous systems

Answer 6

Schwann cells(many round a single axon) in PNS
oligodendrocytes(one round many axons) in CNS

Question 7

describe what saltatory conduction is along myelinated axons

Answer 7

this is when the action potential jumps form one nor of Ranvier to the next
node of Ranvier = gaps between myelin sheath