exam 1 IMPORTANT

Question 1

How can the PNS be divided physiologically?

Answer 1

afferent nervous system & efferent nervous system

Question 2

What is the afferent nervous system?

Answer 2

carries impulses/stimuli INTO brain & spinal cord; sensory division

Question 3

What is the efferent nervous system?

Answer 3

carries impulses/stimuli OUT OF brain & spinal cord to muscles & glands called effectors; motor division

Question 4

What is the ANS divided into?

Answer 4

sympathetic & parasympathetic divisions

Question 5

What are neurons?

Answer 5

cells that can generate, receive, send, & transmit some type of impulse

Question 6

What are the different shapes of neurons?

Answer 6

multipolar, bipolar, & unipolar (pseudounipolar)

Question 7

What does multipolar mean?

Answer 7

many dendrites & 1 axon; found everywhere including the brain

Question 8

What does bipolar mean?

Answer 8

1 dendrite & 1 axon; in sense organs like the retina of the eye

Question 9

What does unipolar (pseudounipolar) mean?

Answer 9

1 extension from the cell body that branches into dendrite & axon; in cranial nerves such as nerves for sense of smell

Question 10

How are neurons classified by function?

Answer 10

afferent, efferent, & association

Question 11

What do afferent, efferent, & association mean?

Answer 11

sensory, motor, & the link to sensory and motor

Question 12

How are neurons classified by myelination?

Answer 12

white matter & gray matter

Question 13

What is white matter?

Answer 13

myelinated neurons; myelin coats the axons

Question 14

What is gray matter?

Answer 14

non-myelinated neurons

Question 15

What are dendrites?

Answer 15

usually short, thick, branched cytoplasmic extensions from the cell body; they receive the impulse

Question 16

What is the axon?

Answer 16

usually 1 long extension that arises from a little bump called an axon hillock

Question 17

The distal end of the axon branches into what?

Answer 17

axon terminals that end in button-like synaptic end bulbs

Question 18

What do the synaptic end bulbs contain?

Answer 18

many synaptic vesicles that store & release neurotransmitter onto the next cell

Question 19

What is the goal of impulse physiology?

Answer 19

to release the neurotransmitter molecules when the neuron is stimulated

Question 20

What is the first step of impulse physiology?

Answer 20

the dendrite ends receive the impulse

Question 21

What does the impulse create in the cytoplasm once it is received?

Answer 21

the impulse causes waves/ripples to go through the ICF

Question 22

What happens if the waves are strong enough to reach the axon hillock?

Answer 22

voltage gated membrane channels will open

Question 23

What is a threshold stimulus?

Answer 23

a stimulus that is strong enough to elicit opening of these channels

Question 24

What is a resting neuron?

Answer 24

a neuron in the body that is not active

Question 25

What 2 areas have a voltage difference between them (in a resting neuron)?

Answer 25

the ICF & ECF

Question 26

What is the resting membrane potential?

Answer 26

the voltage between the ICF & ECF when at rest; -70mV

Question 27

What does the -70mV value mean?

Answer 27

there is a difference in voltage of 70mV AND the ICF has a negative charge

Question 28

What can be found in the ECF & ICF of a resting neuron?

Answer 28

there are many sodium ions in the ECF & many potassium ions in the ICF

Question 29

What happens when the threshold stimulus is applied?

Answer 29

voltage gated channels open; there are 2 types

Question 30

What are the 2 types of voltage gated channels?

Answer 30

voltage gated sodium channel & voltage gated potassium channel

Question 31

What is the voltage gated sodium channel?

Answer 31

it looks like a door that pops open; it opens rapidly allowing Na+ to enter the cytoplasm

Question 32

Why does the Na+ enter the cell?

Answer 32

the concentration gradient & the pull from the negative ICF

Question 33

What happens as the Na+ rush in to the cell?

Answer 33

depolarization; the mV increases; it goes -70, -50, 0, 30

Question 34

What is the voltage gated potassium channel?

Answer 34

looks like twisties; opens slowly, becoming open at about 30mV; allows potassium to exit the cell

Question 35

Why does K+ exit the ICF?

Answer 35

the concentration gradient & the pull from the now slightly negative charge of the ECF

Question 36

What happens as the K+ goes out?

Answer 36

the mV decreases; it goes from 30, 0, -50, -70

Question 37

What happens as the wave of impulse/depolarization reaches the synaptic end bulbs?

Answer 37

Ca++ channels open & Ca++ enters the synaptic end bulbs from the ECF

Question 38

What triggers migration & exocytosis of synaptic vesicles?

Answer 38

calcium ions (Ca++)

Question 39

What is the synapse?

Answer 39

a small space that neurotransmitter molecules diffuse across

Question 40

Where do neurotransmitter molecules go from the synapse?

Answer 40

the “next cell” which can be called the post-synaptic cell

Question 41

What does the Na+/K+ Pump do?

Answer 41

moves 3 Na+ out of cell for every 2 K+ that enter the cell

Question 42

Does the Na+/K+ Pump require ATP (energy)?

Answer 42

yes

Question 43

What is the refractory period?

Answer 43

absolute: the time in which the neuron cannot send an impulse; relative: can fire but requires more stimulation

Question 44

Why does the refractory period occur?

Answer 44

because no impulse can travel though the neuron until the action of the Na+/K+ Pump is complete

Question 45

Where does continuous conduction of the impulse occur?

Answer 45

in neurons that lack myelin; this process causes all voltage gated channels to open

Question 46

Where does salvatory conduction of the impulse occur?

Answer 46

in neurons that are covered in myelin; myelin wraps the axon in discontinuous pieces with unmyelinated nodes in between

Question 47

What are the unmyelinated gaps called?

Answer 47

nodes of ranvier; during depolarization, ONLY the channels in these nodes operate

Question 48

Which kind of conduction of the impulse is faster?

Answer 48

salvatory conduction

Question 49

Under what circumstances would Chlorine ions (Cl-) enter the neuron?

Answer 49

to inhibit release of neurotransmitter & response by the post-synaptic cell

Question 50

What happens to the membrane voltage when Cl- enters the cell?

Answer 50

it decreases because of the negative ion; this makes the axon even more polarized