Chapter 11

Question 1

The function of the nervous system?

Answer 1

Master controlling and communicating

system of body

Question 2

Neuroglia

Answer 2

small cells that surround and

wrap delicate neurons

Question 3

Neurons

Answer 3

excitable cells that

transmit electrical signals

Question 4

Astrocytes are the most abundant CNS neuroglia

Answer 4

Cling to neurons, synaptic endings, and capillaries

Support and brace neurons

Question 5

Microglial cells are defensive cells in the CNS

Answer 5

Migrate toward injured neurons

Question 6

Ependymal cells line cerebrospinal fluid–filled cavities

Answer 6

Line the central cavities of the brain and spinal column

Question 7

Oligodendrocytes

Answer 7

have processes that form myelin

sheaths around CNS nerve fibers

Question 8

Myelin

Answer 8

Whitish, protein-lipoid substance

Question 9

Satellite cells

Answer 9

Surround neuron cell bodies in PNS

Question 10

Schwann cells

Answer 10

Surround all peripheral nerve fibers and form myelin sheaths in thicker nerve
fibers

Question 11

Histology of Nervous Tissue

Answer 11

Highly cellular; little extracellular space Tightly packed Two principal cell types

Question 12

Neuroglia

Answer 12

small cells that surround and wrap delicate neurons

Question 13

Neurons (nerve cells)

Answer 13

excitable cells that transmit electrical signals

Question 14

Types of Histology of Nervous Tissue: Neuroglia

Answer 14

Astrocytes (CNS)
– Microglial cells (CNS)
– Ependymal cells (CNS)
– Oligodendrocytes (CNS)
– Satellite cells (PNS)
– Schwann cells (PNS)

Question 15

Astrocytes are the most abundant CNS neuroglia

Answer 15

Cling to neurons, synaptic endings, and capillaries
Support and brace neurons
Respond to nerve impulses and neurotransmitters

Question 16

Microglial cells are defensive cells in the CNS

Answer 16

Migrate toward injured neurons. Can transform to

phagocytize microorganisms and neuronal debris

Question 17

Ependymal cells line cerebrospinal fluid–filled cavities

Answer 17

Line the central cavities of the brain and spinal column.
Form permeable barrier between cerebrospinal fluid (CSF)
in cavities and tissue fluid bathing CNS cells

Question 18

Oligodendrocytes have processes that form myelin sheaths

around CNS nerve fibers

Answer 18

Protects and electrically insulates axon

Increases speed of nerve impulse transmission

Question 19

Nodes of ranvier

Answer 19

Myelin sheath gaps between adjacent

Schwann cells

Question 20

Interneurons (association neurons)

Answer 20

Lie between motor and sensory neurons
– Shuttle signals through CNS pathways;
most are entirely within CNS
– 99% of body's neurons
– Most confined in CNS

Question 21

Action Potential – know what is happening at each step

Answer 21

Resting state
• Depolarization
• Repolarization
• Hyperpolarization

Question 22

Refractory period

Answer 22

Excitation cannot re-occur for a certain amount of
time
• Thus, signal only moves in one direction

Question 23

A junction that mediates information transfer from

one neuron:

Answer 23

To another neuron, or

– To an effector cell

Question 24

Presynaptic neuron

Answer 24

conducts impulses toward the

synapse

Question 25

Postsynaptic neuron

Answer 25

transmits impulses away

from the synapse

Question 26

The Synapse

Answer 26

A junction that mediates information transfer from

one neuron

Question 27

Graded Potentials

Answer 27

Contrast with action potentials
• Graded: Excitatory postsynaptic potentials and
Inhibitory postsynaptic potentials
o Additive effects
o Usually at dendrites; used to
generate/inhibit action potential

Question 28

50 or more neurotransmitters have been identified

Answer 28

Classified by chemical structure and by function
• Acetylcholine (Ach)
• Released at NMJ and some ANS neurons
• Degraded by the enzyme acetylcholinesterase
(AChE)
• Others: Dopamine, Norepinephrine , Epinephrine,
Serotonin , Histamine, GABA, Endorphins
• Neurotransmitter effects may be excitatory and/or
inhibitory

Question 29

Drugs – how do they act?

Answer 29

. cocaine
• mechanism of action?
• Long-term effects on addiction

Question 30

Nodes of ranvier are present

Answer 30

Myelin Sheaths in the CNS

Question 31

White matter

Answer 31

–Regions of brain and spinal cord with
dense collections of myelinated fibers –
usually fiber tracts

Question 32

Gray matter

Answer 32

Mostly neuron cell bodies and

nonmyelinated fibers

Question 33

Autoimmune disease effects?

Answer 33

affecting primarily young

adults

Question 34

Myelin sheaths in CNS destroyed

Answer 34

Immune system attacks myelin
• Turns it to hardened lesions
called scleroses
– Impulse conduction slows and eventually
ceases
– Unaffected axons increase Na
\+ channels
• Causes cycles of relapse and
remission

Question 35

Symptoms

Answer 35

Visual disturbances, weakness, loss of
muscular control, speech disturbances,
and urinary incontinence

Question 36

Treatment

Answer 36

Drugs that modify immune system’s

activity improve lives

Question 37

Prevention

Answer 37

High blood levels of Vitamin D reduce

risk of development

Question 38

Neuron Cell Body (Perikaryon or Soma)

Answer 38

Most neuron cell bodies in CNS

• Nuclei – clusters of neuron cell bodies in CNS
• Ganglia – lie along nerves in PNS

Question 39

Neuron Processes: Dendrites, Axon

Answer 39

Armlike processes extend from body

Question 40

CNS

Answer 40

Both neuron cell bodies and their processes

Question 41

PNS

Answer 41

Chiefly neuron processes

Question 42

Tracts:

Answer 42

Bundles of neuron processes in CNS

Question 43

Nerves:

Answer 43

Bundles of neuron processes in PNS

Question 44

Sensory

Answer 44

Transmit impulses from sensory receptors
toward CNS
– Almost all are unipolar
– Cell bodies in ganglia in PNS

Question 45

Motor

Answer 45

Carry impulses from CNS to effector
muscles
– Multipolar