human antomy

Question 1

Sensory input—gathering information

Answer 1

To monitor changes occurring inside and
outside the body
-Changes = stimuli

Question 2

Integration

Answer 2

To process and interpret sensory input and
decide if action is needed

Question 3

Motor output

Answer 3

A response to integrated stimuli
- The response activates muscles or glands

Question 3

Peripheral nervous system (PNS)

Answer 3

Nerves outside the brain and spinal cord
- Spinal nerves
- Cranial nerves

Question 4

Central nervous system (CNS)

Answer 4

Brain
- Spinal cord

Question 5

Sensory (afferent) division

Answer 5

Nerve fibers that carry information to the
central nervous system

Question 6

Motor (efferent) division

Answer 6

Nerve fibers that carry impulses away from the
central nervous system

Question 7

Motor (efferent) division (continued)

Answer 7

Two subdivisions
- Somatic nervous system = voluntary
- Autonomic nervous system = involuntary

Question 8

Astrocytes

Answer 8

Abundant, star-shaped cells
- Brace neurons
- Form barrier between capillaries and neurons
- Control the chemical environment of
the brain

Question 8

Support cells in the CNS are grouped together as
“neuroglia”

Answer 8

Function: to support, insulate, and protect
neurons

Question 9

Microglia

Answer 9

Spiderlike phagocytes
- Dispose of debris

Question 9

Ependymal cells

Answer 9

Line cavities of the brain and spinal cord
- Circulate cerebrospinal fluid

Question 9

Nissl substance

Answer 9

Specialized rough endoplasmic reticulum

Question 9

Cell body

Answer 9

Nucleus
- Large nucleolus

Question 10

Schwann cells

Answer 10

Form myelin sheath in the peripheral nervous
system

Question 10

Satellite cells

Answer 10

Protect neuron cell bodies

Question 11

Oligodendrocytes

Answer 11

Wrap around nerve fibers in the central
nervous system
- Produce myelin sheaths

Question 12

Myelin sheath

Answer 12

whitish, fatty material covering
axons

Question 12

Neurons = nerve cells

Answer 12

Cells specialized to transmit messages

Question 12

Major regions of neurons

Answer 12

Cell body—nucleus and metabolic center
of the cell
- Processes—fibers that extend from the
cell body

Question 13

Axons end in axonal terminals

Answer 13

Axonal terminals contain vesicles with
neurotransmitters

Question 13

Neurofibrils

Answer 13

Intermediate cytoskeleton
 Maintains cell shape

Question 14

Nodes of Ranvier

Answer 14

gaps in myelin sheath along
the axon

Question 14

Processes outside the cell body

Answer 14

Dendrites—conduct impulses toward the cell
body
- Axons—conduct impulses away from the cell
body

Question 14

Schwann cells

Answer 14

produce myelin sheaths in jelly roll–like fashion

Question 14

Axonal terminals are separated from the next neuron by a gap

Answer 14

Synaptic cleft—gap between adjacent neurons - Synapse—junction between nerves

Question 14

Most neuron cell bodies are found in the central nervous system

Answer 14

Gray matter—cell bodies and unmyelinated fibers - Nuclei—clusters of cell bodies within the white matter of the central nervous system

Question 14

Sensory (afferent) neurons

Answer 14

Carry impulses from the sensory receptors to the CNS  Cutaneous sense organs  Proprioceptors—detect stretch or tension

Question 15

Ganglia

Answer 15

collections of cell bodies outside the central nervous system

Question 15

Motor (efferent) neurons

Answer 15

Carry impulses from the central nervous system to viscera, muscles, or glands

Question 15

Interneurons (association neurons)

Answer 15

 Found in neural pathways in the central nervous system  Connect sensory and motor neurons

Question 15

Multipolar neurons

Answer 15

many extensions from the cell body

Question 16

Bipolar neurons

Answer 16

one axon and one dendrite

Question 17

Unipolar neurons

Answer 17

have a short single process leaving the cell body

Question 18

Irritability

Answer 18

Ability to respond to stimuli

Question 19

what does the exchange of ions do

Answer 19

The exchange of ions initiates an action potential in the neuron

Question 19

Conductivity

Answer 19

Ability to transmit an impulse

Question 19

Repolarization

Answer 19

 Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane  The sodium-potassium pump, using ATP, restores the original configuration

Question 19

Action potential

Answer 19

 If the action potential (nerve impulse) starts, it is propagated over the entire axon  Impulses travel faster when fibers have a myelin sheath

Question 20

Resting neuron

Answer 20

 The plasma membrane at rest is polarized  Fewer positive ions are inside the cell than outside the cell

Question 21

Depolarization

Answer 21

 A stimulus depolarizes the neuron’s membrane  A depolarized membrane allows sodium (Na+) to flow inside the membrane

Question 21

Impulses are able to cross the synapse to another nerve

Answer 21

 Neurotransmitter is released from a nerve’s axon terminal  The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter  An action potential is started in the dendrite