12.9 Characteristics of action potentials.

Question 1

Graded potentials

Answer 1

Happen in the receptive segment of the neuron
Chemically gated channels cause this
Signal dies out
Short lived
travel short distances

Question 2

Action potentials

Answer 2

Generated in the initial segment of the neuron
Voltage gated channels cause this
Signal maintains its strength and travels relatively long distances.
Self propagating
These follow the all or none law

Question 3

What effects the velocity of action potential?

Answer 3

Diameter of axon- greater diameter=great velocity

Myelination- myelination=greater velocity.

Question 4

Nerve fiber

Answer 4

Axon and myelin sheath.

Question 5

Group A nerve fibers

Answer 5

velocity of 150 m per second

Most sensory neurons and all motor neurons

Question 6

Group B nerve fibers

Answer 6

velocity of 15 m per second
small in diameter and unmyelinated
Visceral sensory and autonomic neurons and small somatic sensory neurons that extend from the receptors of the skin to the CNS.

Question 7

Group C nerve fibers

Answer 7

velocity of 1 m per second
small in diameter and unmyelinated
Visceral sensory and autonomic neurons and small somatic sensory neurons that extend from the receptors of the skin to the CNS.

Question 8

Action potential strength and frequency

Answer 8

Strength of the action potential always remains the same
Frequency of the action potential increases as the strength of the stimulus increases. Frequency can also be effected by the type of neurotransmitter.