chapter 5

Question 1

what creates diffusion potentials?

Answer 1

ion concentrations and charges

Question 2

nernst potential

Answer 2

the diffusion potential across a membrane that opposes net diffusion of a particular ion

Question 3

what positive ions diffuse OUT of a cell to make it more negative?

Answer 3

K+

Question 4

what positive ion diffuse into the cell to make it more positive?

Answer 4

Na+

Question 5

what negative ions diffuse into the cell to make it more negative?

Answer 5

Cl-

Question 6

efflux

Answer 6

leaving the cell

Question 7

influx

Answer 7

entering the cell

Question 8

what is the resting membrane potential value?

Answer 8

-70mV

Question 9

Na+/K+ pump (ATPase pump)

Answer 9

3 Na+ OUT, 2 K+ IN

Question 10

step 1 of membrane potentials

Answer 10

Na+/K+ pump occurs. K+ then leaves cell through leak channels

Question 11

what is the mV value after Na+/K+ pump?

Answer 11

-4mV

Question 12

what is the mV value after K+ leaves through leak channels?

Answer 12

-68mV

Question 13

step 2 of membrane potentials

Answer 13

positive ion enters to summate to threshold

Question 14

step 3 of membrane potentials

Answer 14

threshold is reached by Na+ in through voltage gated channels & Na+ channels close at peak

Question 15

step 4 of membrane potentials

Answer 15

K+ channels open to start repolarization. K+ re-exits cell

Question 16

step 5 of membrane potentials

Answer 16

hyperpolarization is reached when K+ channels close

Question 17

temporal summation

Answer 17

2 or more presynaptic inputs arrive at postsynaptic cell in rapid succession

Question 18

spatial summation

Answer 18

2 or more presynaptic inputs arrive at postsynaptic cell simultaneously

Question 19

depolarization

Answer 19

process of making the membrane potential less negative by influx of positive ions

Question 20

hyperpolarization

Answer 20

process of making the membrane potential more negative by the efflux of positive ions

Question 21

threshold potential

Answer 21

the membrane potential where an action potential is created

Question 22

overshoot

Answer 22

the portion of the action potential when the membrane potential is a positive value

Question 23

undershoot/hyperpolarization

Answer 23

the portion of the action potential where the membrane potential is more negative than resting value

Question 24

absolute refractory period

Answer 24

no matter how great the stimulus, another AP cannot be generated

Question 25

relative refractory period

Answer 25

another AP can be generated but requires a larger stimulus

Question 26

what causes a sustained hypopolarization of a cell membrane?

Answer 26

hyperkalemia

Question 27

conduction velocity

Answer 27

the speed APs are conducted along a nerve or muscle fiber

Question 28

saltatory conduction

Answer 28

the process of an AP jumping from node to node

Question 29

what is the most common NT released into synaptic cleft?

Answer 29

ACH (acetylcholine)

Question 30

types of synapses

Answer 30

one-to-one synapse, one-to-many synapse, excitatory postsynaptic potentials, + inhibitory postsynaptic potentials

Question 31

one-to-one synapse

Answer 31

neuromuscular junctions

Question 32

many-to-one synapse

Answer 32

rare, renshaw cells of spinal cord

Question 33

excitatory postsynaptic potentials

Answer 33

cause depolarization of postsynaptic cell. glutamate/ACH

Question 34

inhibitory postsynaptic potentials

Answer 34

cause hyperpolarization of postsynaptic cell. GABA

Question 35

Chemical gradient

Answer 35

Concentration gradient, kinetic or thermal energy

Question 36

Electrical gradient

Answer 36

Charges want to neutralize. The negative proteins inside the cell attract pos ions in and repel neg ions

Question 37

Goldman equation

Answer 37

The membrane potential of an excitable membrane is determined by the nernst potentials of each of the ions that the membrane is selectively permeable to

Question 38

What factors affects the Goldman equation?

Answer 38

The polarity of the electrical charge of each ion, the permeability of the membrane to that ion, concentration of each ion on the inside of the membrane vs the outside

Question 39

Accommodation

Answer 39

Stuck in absolute refractory period bc the membrane does not return to resting level and Na+ channels cannot be reset

Question 40

What does accommodation result in?

Answer 40

Slow depolarization or hypo-polarized state

Question 41

Alpha-1 adrenergic receptors

Answer 41

For constriction of blood vessels or contraction of a smooth muscle

Question 42

Beta-1 adrenergic receptors

Answer 42

For the heart SA node and cardiac muscle

Question 43

Beta-2 adrenergic receptors

Answer 43

For dilation of vessels and bronchi

Question 44

Small motor units

Answer 44

1 neuron innervates only a few muscle fibers. For fine dexterous control

Question 45

Larger motor units

Answer 45

1 neuron innervates many muscle fibers. For gross muscle activity