Chapter 48 Electrical Signal in Animals

Question 1

Axon hillock

Answer 1

connects end of nerve body to axon

-cone shaped

Question 2

3 types of neurons

Answer 2

1. Sensory neuron
2. Interneuron
3. Motor neuron

Question 3

Membrane potential

Answer 3

concentration gradient of electrochemical ion across the membrane

Question 4

Resting potential

Answer 4

-membrane potential of resting cell (non-excitable neuron) that does not send electrical signals
-70mV (internal environment of cell is more negative than outside)
-membrane potential maintained by Na+/K+ pump and leaky K+ channel
(3 Na+ moves out, 2K+ moves in)

Question 5

Action potential

Answer 5

-electrical signal (impulse) that moves along the membrane of the neuron
-huge change in membrane voltage (caused by depolarization)
-all-or-non response - occurs in non-graded depolarization manner
+30mV

Question 6

Acetylcholine

Answer 6

• neurotransmitter that is both excitatory and inhibitory

* but in scull contraction, works as an excitatory neurotransmitter