Chapter 4 (Physiology)

Question 1

The Nervous System:

Answer 1

Neural communication accomplished by nerve cells (neurons)

Short, rapid

Question 2

The Endocrine System:

Answer 2

Hormonal communication accomplished by hormones

Long distance messengers

Question 3

RMP

Answer 3

At rest, all cells have a negative internal charge & unequal distribution of ions:

The membrane potential that exists when an excitable cell is not displaying an electrical signal. Typically at -70mV

Question 4

Polarization

Answer 4

Any state when the membrane potential is other than 0mV

Question 5

Depolarization

Answer 5

Membrane becomes less polarized than at resting potential

Question 6

Repolarization

Answer 6

Membrane returns to resting potential after having been depolarized

Question 7

Hyperpolarization

Answer 7

Membrane becomes more polarized than at resting potential

Question 8

Graded potentials

Answer 8

Serve as short-distance signals
Occurs in small, specialized region of excitable cell membranes
Magnitude varies by triggering event

Question 9

Action potentials

Answer 9

Serve as long-distance signals
Brief, rapid, large (100mV) changes in membrane potential during which potential actually reverses
Do not decrease in strength

Question 10

Contiguous conduction

Answer 10

Conduction in unmyelinated fibers

Action potential spreads along every portion of the membrane

Question 11

Saltatory conduction

Answer 11

Rapid conduction in myelinated fibers

Impulse jumps over sections of the fiber covered with insulating myelin

Question 12

The All or None Law

Answer 12

Action potentials occur in all or none fashion depending on the strength of the stimulus

Question 13

The Refractory Period

Answer 13

Is responsible for setting up limit on the frequency of action potentials
Absolute: unresponsive
Relative: capable, need a stronger trigger

Question 14

Myelination

Answer 14

Increases speed of conduction of AP
Myelinated fibers are axons covered with myelin 
Acts as insulator 
Schwann (PNS)
Oligodendrocytes (CNS)

Question 15

Synapse:

Answer 15

Junction between two neurons