Chapter 1

Question 1

absolute refractory period

Answer 1

Na+ gates are incapable of opening; hence, an action potential cannot occur regardless of the amount of stimulation.

Question 2

action potentials

Answer 2

a rapid depolarization of the neuron

Question 3

afferent axon

Answer 3

two axons

carry signals to the brain and spinal cord as sensory data

Question 4

axon

Answer 4

in neuron- transmission
can have many dendrites, but only 1 axon
faster transmission with mylin and diameter size

Question 5

Cell body

Answer 5

in neuron- Integration/Summation

Question 6

dendrites

Answer 6

in nueron- input

Question 7

depolarize

Answer 7

refers to decreasing the
polarization towards zero

occurs when the negative charge inside the axon decreases

Question 8

efferent axon

Answer 8

send signals from the brain to the muscles, glands and organs of the body in response to sensory input

Question 9

electrical gradient

Answer 9

polarization, difference in electrical charge between inside and out of cell

Question 10

gila

Answer 10

removing excess neurochemicals
removing debris
critical role in brain development, and brain damage
control blood flow 
*forms myelin

Question 11

Local anesthetic drugs

Answer 11

block sodium channels and therefore prevent

action potentials from occurring

Question 12

microglia

Answer 12

the first and main form of active immune defense in the central nervous system (CNS).

Question 13

nodes of Ranvier

Answer 13

short unmyelinated sections on a myelinated axon

Question 14

oligodendrocytes

Answer 14

production of myelin in the central nervous system

Question 15

relative refractory period

Answer 15

a stronger than normal stimulus is needed to elicit neuronal excitation

after absolute refractory period, Na+ channels begin to recover from inactivation and if strong enough stimuli are given to the neuron, it may respond again by generating action potentials

Question 16

resting potential

Answer 16

difference in voltage
the electrical potential of a neuron or other excitable cell relative to its surroundings when not stimulated or involved in passage of an impulse

Question 17

saltatory conduction

Answer 17

the “jumping” of the action potential from node to node.

Question 18

Schwann cells

Answer 18

any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons

Question 19

concentration gradient

Answer 19

difference in distribution of ions between the inside and the outside of the membrane

Question 20

sodium-potassium pump threshold

Answer 20

repeatedly transports 3 sodium ions out while drawing 2 potassium ions in
active transport, requires energy

Question 21

hyperpolarization

Answer 21

increased polorization

occurs when the negative charge inside the axon increases

Question 22

propagation of the action potential

Answer 22

transmission (movement) of an action potential down an
axon
the action potential moves down the axon by regenerating itself at successive points on the axon.

Question 23

myelinated axons

Answer 23

Axons covered with a myelin sheath. The myelin sheath is found only in vertebrates and is composed mostly of fats

Question 24

Molecular Basis of action P

Answer 24

1. Sodium mostly outside, potassium mostly in
2. When membrane is depolarized, NA and K channels open
3. At peak of action p, sodium channels close

Question 25

voltage gated channels

Answer 25

regulate Na and K | permeability depends on voltage difference accross the membrane

Question 26

local neurons

Answer 26

no axon, small | only communicate to closest neurons