Nervous System Cells

Front 1

Central nervous system (CNS)

Back 1

Structural and functional center of entire nervous system
• Consists of the brain and the spinal cord
• Integrates sensory information, evaluates it, and initiates
an outgoing response

Front 2

Peripheral nervous system (PNS)

Back 2

• Nerves that lie in “outer regions” of nervous system
• Cranial nerves —originate from brain
• Spinal nerves —originate from spinal cord

Front 3

Afferent division

Back 3

consists of all incoming sensory pathways

Front 4

Efferent division

Back 4

consists of all outgoing motor pathways

Front 5

Somatic nervous system (SNS)

Back 5

• Somatic sensory division —carries feedback information
to somatic integration centers in the CNS; Afferent fibers

• Somatic motor division —carries information to the
somatic effectors (skeletal muscles); Efferent fibers.

Front 6

Autonomic nervous system (ANS)

Back 6

• Afferent (visceral sensory) division—carries feedback
information to autonomic integrating centers in the CNS
• Efferent division of ANS —carries information to the autonomic or visceral effectors (smooth and cardiac muscles and glands)

Front 7

Sympathetic division

Back 7

prepares the body to deal with immediate threats to the internal environment; produces ““fight or flight” response

Front 8

Parasympathetic division

Back 8

coordinates the body’s normal resting activities; sometimes called the “rest and repair” division

Front 9

Five major types of glia

Back 9

• Astrocytes (in CNS)
• Microglia (in CNS)
• Ependymal cells (in CNS)
• Oligodendrocytes (in CNS)
• Schwann cells (in PNS)

Front 10

Astrocytes (in CNS)

Back 10

Star-shaped, largest, and most numerous type of glia

Astrocytes transfer nutrients from the blood to the neurons

Form tight sheaths around brain capillaries, which, with tight junctions between capillary endothelial cells, constitute the blood-brain barrier (BBB)

Front 11

Microglia (in CNS)

Back 11

Small, usually stationary, cells

In inflamed brain tissue, they enlarge, move about, and carry on phagocytosis

Front 12

Ependymal cells (in CNS)

Back 12

Resemble epithelial cells and form thin sheets that line fluid filled cavities ( ventricles) in the CNS

Front 13

Oligodendrocytes (in CNS)

Back 13

Hold nerve fibers together and produce the myelin sheath

Front 14

Schwann cells (in PNS)

Back 14

Found only in PNS

Support nerve fibers and form myelin sheaths

Gaps in the myelin sheath are called nodes of Ranvier
tha increase conduction velocity

Front 15

Neurons

Back 15

Excitable cells that initiate and conduct impulses that make possible all nervous system functions

Front 16

Cell body (perikaryon)

Back 16

Ribosomes, rough endoplasmic reticulum (ER), Golgi apparatus

Front 17

Dendrites

Back 17

Conduct nerve signals to the cell body of the neuron

Front 18

Axon

Back 18

Conducts nerve impulses away from the cell body of the
neuron

Front 19

Multipolar

Back 19

One axon and several dendrites

Front 20

Bipolar

Back 20

Only one axon and one dendrite

Least numerous kind of neuron

Front 21

Unipolar (pseudounipolar)

Back 21

one process comes off
neuron cell body but divides almost immediately into two
fibers: central fiber and peripheral fiber

Front 22

Afferent neurons

Back 22

-sensory

-conduct impulses to spinal cord or brain

Front 23

Efferent neurons

Back 23

-motor

-conduct impulses away from spinal cord or brain toward muscles or glandular tissue

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Three-neuron arc

Back 24

Most common common

Consists of afferent neurons, interneurons, and efferent
neurons

Front 25

Two-neuron arc

Back 25

Simplest form

Consists of afferent and efferent neurons

Front 26

Synapse

Back 26

• Where nerve signals are transmitted from one neuron
to another
• Two types: electrical and chemical

Chemical are typical in the adult

Front 27

Nerves

Back 27

bundles of peripheral nerve fibers held together by several layers of connective tissue

Front 28

What are the Three types of Nerves?

Back 28

- Endoneurium
- Perineurium
- Epineurium

Front 29

Endoneurium

Back 29

delicate layer of fibrous connective tissue surrounding each nerve fiber

Front 30

Perineurium

Back 30

connective tissue holding together fascicles (bundles of fibers)

Front 31

Epineurium

Back 31

fibrous coat surrounding numerous fascicles and blood vessels to form a complete nerve

Front 32

Tracts

Back 32

within the CNS, bundles of nerve fibers are called tracts rather than nerves

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White matter

Back 33

PNS- myelinated nerves

CNS- myelinated tracts

Front 34

Gray matter

Back 34

Made up of cell bodies and unmyelinated fibers

-CNS- Referred to as nuclei

PNS- Referred to as ganglia

Front 35

Electrical synapses

Back 35

occur where cells joined by gap junctions allow an action potential to simply continue along postsynaptic membranecontinue membrane

Front 36

Chemical synapses

Back 36

occur where presynaptic cells release chemical transmitters (neurotransmitters) across a tiny gap to the postsynaptic cell, possibly inducing an action potential thereinducing there