Exam 2: Nervous System I

Question 1

Central Nervous System

Answer 1

• brain and spinal cord
• control center
• president

Question 2

Peripheral Nervous System (PNS)

Answer 2

• cranial nerves, spinal nerves and ganglia
• ganglion=group of neuron cell bodies located outside CNS
• workers

Question 3

Sensory (afferent) Division

Answer 3

receives information FROM body and transmits it TO CNS for processing
-has both CNS and PNS parts

Question 4

Somatic Sensory

Answer 4

• part of sensory division

- receives sensory information from skin, joints, muscle, special senses (vision, hearing, balance, smell, taste)

Question 5

Visceral Sensory

Answer 5

• part of sensory division

- receives sensory info from blood vessels and viscera

Question 6

Motor Division

Answer 6

transmits info FROM the CNS To muscles and glands

-has both CNS and PNS parts

Question 7

Somatic Motor

Answer 7

• part of motor division
• innervate skeletal muscle
• voluntary

Question 8

Autonomic Motor

Answer 8

• part of motor division
• innervates smooth muscle, cardiac muscle, and glands of viscera (organs)
• involuntary

Question 9

Neurons

Answer 9

• respond to stimuli and conduct nerve impulses

- primarily amitotic

Question 10

Glial Cells

Answer 10

• support and protect neurons
• many more glial cells than neurons
• divide by mitosis

Question 11

Cell Body of Neuron

Answer 11

-function: neuron’s control center or head

Question 12

Nucleus

Answer 12

• -houses DNA

- contains nucleolus for protein synthesis

Question 13

Chromatophilic substances (Nissl bodies)

Answer 13

• rough ER inside cell body
• function: protein synthesis
• look like darkened clumps within cytoplasm
• no chromatophilic substance in axon hillock

Question 14

Dendrites

Answer 14

• short nerve cell process
• function: receive input (incoming nerve impulses)
• send nerve cells to cell body
• neuron can have 1 or many dendrites

Question 15

Axon

Answer 15

• long nerve cell process
• function: send output (outgoing nerve impulses
• one axon per neuron

Question 16

Axon Hillock

Answer 16

• portion of the cell body from where the axon originates

- no chromatophilic substance here

Question 17

Multipolar Neuron

Answer 17

• one axon and many dendrites
• most common
• ex: motor neurons, interneurons

Question 18

Bipolar Neuron

Answer 18

• two processes: one axon and one dendrite
• limited in location (rare)
• ex: retina of eye, olfactory neurons in nose

Question 19

Unipolar (Pseudounipolar) Neuron

Answer 19

• Single process comes off of the cell body and divides into two branches
• common
• most (not all) sensory neurons

Question 20

Sensory (afferent) Neuron

Answer 20

• brings information TO CNS

- either unipolar or bipolar neurons

Question 21

Motor (efferent) Neuron

Answer 21

• takes information FROM CNS to other parts of the body

- all are multipolar

Question 22

Interneuron

Answer 22

• help coordinate and integrate info between sensory and motor neurons
• located solely in CNS
• “translator/mediator”
• multipolar in form

Question 23

Neuron Classification

Answer 23

-by structure or by function

Question 24

Satellite Cells

Answer 24

• In PNS
• surround neuron cell bodies in spinal ganglia
• protect the cell bodies
• regulate nutrient exchange and waste removal

Question 25

Neurolemmocytes (Schwann Cells)

Answer 25

• myelinate axons in PNS
• myelin is a protective covering around axon that insulates axon and helps produce faster nerve impulses
• can also help regenerate damaged PNS axons

Question 26

Astrocytes

Answer 26

• in CNS
• regulate transfer of materials from blood to the brain, help workings of BBB
• helps make blood vessels less leaky

Question 27

Blood Brain Barrier

Answer 27

• keeps harmful substances away from brain
• selectively permeable
• bust some needed substances can’t pass this barrier either like chemotherapy drugs

Question 28

Astrocytes and the BBB (Parkinsons)

Answer 28

• caused by a decrease of a dopamine
• dopamine can’t pass the BBB but a related drug, L-dopa, can.
• Cocaine and methamphetamine pass through and damage BBB

Question 29

Oligodendrocytes

Answer 29

• myelinates multipe axons in CNS

- to CNS as neurolemmocytes are to PNS

Question 30

Microglia

Answer 30

• phagocytize damaged neurons in CNS

- replicate when there is CNS damage and need to clean up an area

Question 31

Ependymal Cells

Answer 31

• line central canal and ventricles of CNS
• help circulate CSF
• central canal and ventricles are spaces within the spinal cord and brain respectively

Question 32

Myelination

Answer 32

• process of wrapping an axon with myelin
• myelin insulates axon, produces a faster nerve impulse
• dendrites are not myelinated

Question 33

Myelination Procedure in PNS

Answer 33

• Neurolemmocyte wraps around a 1 mm portion of an axon successively
• Cytoplasm and nucleus of neurolemmocyte gets “squeezed” to the outside
• inner successive layers of cell membrane make up the myelin sheath of neurolemocyte

Question 34

Neurofibril Nodes (Nodes of Ranvier)

Answer 34

• separate neurolemmocytes
• axon unmyelinated here
• nerve impulse is generated at these nodes

Question 35

Myelination in CNS

Answer 35

• one oligodendroyte myelinates 1 mm portions of many axons

- similar to PNS but oligodendrocytes myelinate CNS axons