Ch 2 - Properties of Cells in NS

Question 1

Soma

Answer 1

synthesizes a large quantity and variety of proteins used as NT

Question 2

Dendrites

Answer 2

Branchlike extensions that serve as main input site for the cell

Question 3

Axon

Answer 3

Output unit of the cell, specialized to send info to other neurons, muscle cells, or glands

Question 4

Presynaptic terminals

Answer 4

transmit elements of the neuron

Question 5

Synaptic cleft is

Answer 5

the space between neurons and serves as site for interneuronal communication

Question 6

axoplasmic transport

Answer 6

mechanism for transporting substances along an axon

Question 7

Two directions of axoplasmic transport

Answer 7

anterograde

retrograde

Question 8

Multipolar neurons

Answer 8

multiple dendrites arising from many regions of the cell body and a single axon

Question 9

Multipolar neurons specialized to

Answer 9

receive and accommodate huge amounts of synaptic input to their dendrites

Question 10

4 types of membrane channels

Answer 10

Leak channels
Modality gated channels
Ligand gated channels
Voltage gated channels

Question 11

Three types of electrical potentials essential for transmitting info

Answer 11

Resting membrane potential
Local potential - either excitatory or inhibitory
AP - all or nothing, always excitatory

Question 12

Sensory neurons receiving sites are the

Answer 12

sensory receptors

Question 13

Motor and interneurons receiving sites are on the

Answer 13

postsynaptic membrane

Question 14

Local potential define

Answer 14

initial change in membrane potential

Question 15

Action potential - change from local that results in

Answer 15

depolarization

Question 16

Local potentials are categorized as either

Answer 16

receptor potentials or synaptic potentials

Question 17

Receptor potentials

Answer 17

generated at a peripheral receptor of a sensory neuron

Question 18

Synaptic potentials

Answer 18

generated at a postsynaptc membrane

Question 19

Local potentials can only spread

Answer 19

passively - they are confied to a small area of the membrane

Question 20

Local receptor potentials are generated when

Answer 20

the peripheral receptors of a sensory neuron are stretched, compressed, deformed, or exposed to thermal or chemical agents

Question 21

Local synaptic potentials are generated in ___ when ___

Answer 21

in motor neurons and interneurons when they are stimulated by input from other neurons

Question 22

Temporal summation

Answer 22

combined effect of a series of small potential changes that occur within ms of each other

Question 23

Spatial summation

Answer 23

process by which either receptor or synaptic potentials generated in diff regions of the neuron are added together

Question 24

Three events for AP

Answer 24

Rapid depolarization (Na open)
Decrease in Na conduction (channels close)
Rapid repolarization (K channels open)

Question 25

Refractory period divided into two states

Answer 25

Absolute - unresponsive to stimuli

Refractory - may be hypepolarized

Question 26

Thicker myelination leads to

Answer 26

faster conduction and greater changes for AP propogation

Question 27

Convergence

Answer 27

multiple inputs from a variety of cells terminate on a single neuron

Question 28

Divergence

Answer 28

single neuron with many branches that terminate on a multitude of cells

Question 29

Macroglial cells - groups

Answer 29

Astrocytes
Oligodendrocytes
Schwann cells

Question 30

___ myelinate neurons in the CNS

Answer 30

oligodendrocytes

Question 31

___ myelinate neurons in the PNS

Answer 31

schwann cells

Question 32

Guillain Barre Syndrome

Answer 32

acute inflammation and demyelination of peripheral sensory and motor fibers

Question 33

Guillain Barre Syndrome

Answer 33

Occurs 2 to 3 weeks after mild infection

Question 34

Multiple Sclerosis

Answer 34

Immune system produces antibodies that attack oligodendrocytes, producing plaques in white matter

Question 35

MS - 4 types

Answer 35

Relapsing/remitting
Secondary progressive
Primary progressive
Progressive relapsing

Question 36

Which structure receives synaptic input from other neurons

Answer 36

dendrite

Question 37

Which structure releases the NT

Answer 37

presynaptic terminal

Question 38

Afferent neurons convey info

Answer 38

from peripheral receptors to the CNS

Question 39

Resting membrane potential is maintained by

Answer 39

active transport of Na ions and K and passive diffusion of Na, K, Cl through the cell membrane

Question 40

Depolarization occurs when

Answer 40

the membrane potential becomes less negative than the resting membrane potential

Question 41

Local potentials

Answer 41

are either receptor or synaptic potentials
spread passively onle a short distance
result from stimulation of sensory receptors or from binding of NT with chemical receptor sites on a postsynaptic membrane

Question 42

Propogation of an AP along an axon is dependent on

Answer 42

anterograde diffusion of the electric potential with active generation of new potentials

Question 43

Demyelination of an axon results in

Answer 43

dec membrane resistance allowing a leakage of electrical current
slowed propogation of AP
May prevent propagation of APs

Question 44

Peripheral demyelination typically affects

Answer 44

schwann cells of large, well myelinated axons

Question 45

MS results from

Answer 45

attack on oligodendrocytes (CNS)

has signs ans sx associated with motor and sensory

Question 46

Ex of divergence

Answer 46

signals in a pathway that leads to contraction of several hip flexor muscles when painful stimulus applied to toe