Chapter 12 [ EXAM #1 ]

Question 1

define innervation

Answer 1

nerve supply (motor and sensory)

Question 2

what is the CNS composed of?

Answer 2

brain and spinal cord

Question 3

what is the PNS composed of?

Answer 3

nervous tissue

nerve fibers

peripheral nerves:

• spinal
• cranial

Question 4

what is the job of the CNS?

Answer 4

integrating, processing and coordinating sensory data and motor commands

Question 5

how is the CNS organized?

Answer 5

nuclei (cell bodies)

tracts (axons)

Question 6

what is the job of the PNS?

Answer 6

delivers sensory info into the CNS

carries motor commands out from the CNS

Question 7

what is the PNS composed of?

Answer 7

nerves (axons)

ganglia (nervous tissue, cell bodies)

Question 8

what is afferent division integration

Answer 8

processes sensory info, analyzes, makes decisions

Question 9

what is efferent division?

Answer 9

produces appropriate motor response by activating effectors (e.g. muscles, glands)

Question 10

somatic nervous system

Answer 10

voluntary: conscious skeletal muscle contraction

reflexes:
involuntary contractions

Question 11

autonomic nervous system

Answer 11

visceral motor

involuntary, unconscious

cardiac muscle, smooth muscle, glands

sympathetic and parasympathetic

Question 12

parasympathetic nervous system

Answer 12

“rest of digest”

conserves energy

promotes house-keeping functions during rest

Question 13

sympathetic nervous system

Answer 13

“fight or flight”

mobilizes body systems during activity

Question 14

visceral sensory

Answer 14

unconscious

organs

Question 15

somatic sensory

Answer 15

conscious

skin, skeletal muscles

Question 16

nervous tissue

Answer 16

very cellular

neurons: excitable nerve cells, functional units
neuroglia: supporting (glue) cells

Question 17

neurons

Answer 17

variable sizes

long-lived and amitotic

high metabolic rate (glucose and O2)

electrically excitable (respond to stimuli, produce action potential)

Question 18

action potential

Answer 18

electrical signal that moves along neuron membrane

Question 19

neurofibrils

Answer 19

facilitate shape

Question 20

neurotubules

Answer 20

facilitates motility (ribosome transport down axon)

Question 21

dendrite spine

Answer 21

increase SA:V of dendrites

Question 22

neuron plasma membrane components

Answer 22

axoplasm and axolemma

Question 23

axon collateral

Answer 23

branches off the axon into more terminals

Question 24

presynaptic cell

Answer 24

sends neurotransmitters

Question 25

postsynaptic cell

Answer 25

receives neurotransmitters

Question 26

neurotransmitters

Answer 26

released from synaptic vesicles in synaptic (axon) terminal

diffuse through synaptic cleft, bind to postsynaptic cell receptors

Question 27

axoplasmic transport

Answer 27

movement between cell body and synaptic terminal

monorail system, neurotubules

Question 28

anterograde axoplasmic transport

Answer 28

cell body to axon terminals, replenish neurotransmitters

Question 29

retrograde axoplasmic transport

Answer 29

axon terminal to cell body (growth factor, rabies)

Question 30

interneurons

Answer 30

association neurons

in brain and spinal cord

more interneurons = more complex respons (learning, memory)

Question 31

neuroglia

Answer 31

supporting cells

in CNS:
astrocytes
microglia
ependymal cells
oligodendrocytes

in PNS:
satellite cells
Schwann cells

Question 32

myelination

Answer 32

axons surrounded by multi-layered myelin sheath

electricity insulates, increases nerve impulse speed

Question 33

nodes on Ranvier

Answer 33

gaps between internodes

Question 34

gray vs white matter

Answer 34

white: mainly myelinated axons
gray: dense neuronal cell bodies, dendrites, unmyelinated axons

Question 35

transmembrane potential

Answer 35

pos. and neg. ions held apart by selectively permeable membrane

varies with cell activity

determined by activity of passive and active forces

Question 36

resting membrane potential

Answer 36

transmembrane potential at res (~70mV)

Question 37

current

Answer 37

ion flow

Question 38

resistance

Answer 38

interferes with ion current

Question 39

chemical gradient

Answer 39

difference in concentration

K+ moves out

Na+ moves in

Question 40

electrical gradiant

Answer 40

difference in charge

neg. insides, pos. outside

Na+ moves in

Question 41

electrochemical gradient

Answer 41

difference in concentration of chemicals and electric charge

influences movement and establishes resting membrane potential

membrane very permeable to K+, K+ moves out

membrane somewhat permeable to Na+

Question 42

leak (passive) channels

Answer 42

always open, differ between ions; establish resting membrane potential

Question 43

gated (active) channels

Answer 43

closed at resting membrane potential, open/close in response to stimuli

Question 44

chemically (ligand) gated channels

Answer 44

present in dendrites and neuron cell bodies

open/close when bind to specific chemical

Question 45

voltage gated channels

Answer 45

present in unipolar and multipolar neuron axons

in excitable membrane (that generate AP)

open/close to change membrane potential

activation and inactivation gates

Question 46

mechanically gated channels

Answer 46

present in dendrites and neuron cell bodies

not present in axons

in response to physical distortion of membrane: touch, stretch, vibration

Question 47

depolarization

Answer 47

less neg. and more pos. resting membrane potential

Question 48

repolarization

Answer 48

removal of stimulus, returns to resting membrane potential after depolarization

more neg. and less pos.

Question 49

hyperpolarization

Answer 49

membrane more neg. than resting potential

Question 50

graded potential

Answer 50

local changes in transmembrane potential

Question 51

ratio of Na : K gates

Answer 51

3 Na : 2 K