overview of nervous system

Question 1

What is nervous system responsible for?

Answer 1

behaviors, memories, and movements

Question 2

3 functions of NS

Answer 2

1. Sensory: afferent nerves
2. Integrative: association or interneurons
3. motor: efferent neurons

Question 3

NS divisions

Answer 3

CNS: brain and spinal cord
PNS: cranial and spinal nerves –> sensory and motor fibers–> connects CNS to muscles, glands, and receptors

Question 4

PNS Divisions

Answer 4

Somatic NS = neurons from cutaneous and special sense neurons to CNS & motor neurons to skeletal muscles

Autonomic NS = sensory neurons from visceral organs to CNS & motor neurons to smooth and cardiac muscles (sympathetic and parasympathetic)

Enteric NS = involuntary sensory and motor neurons controlling GI tract (function independantly of ANS and CNS)

Question 5

Neurons

Answer 5

• func. unit of NS
• capable of producing AP
• 1 nucleus w/ prominant nucleolus
• not centriole –> don’t divide
• Nissl bodies (chromatophillic substance) = RER and free ribososmes for protein synth
• neurofilaments structure cell
• microtubules move stuff w/in cell
• lipofuscin pigment clumps (harmless aging)

Question 6

structural classification of neurons

Answer 6

1. Multipolar = many dendrites, 1 axon –> motor
2. Bipolar = one dendrite, one axon –> special senses
3. Unipolar = 1 process, divided –> sensory neurons

Question 7

axonal transport (definition and slow vs fast)

Answer 7

• cell body is location for most protein synth
• slow axonal flow = 1-way flow (away) –> 1-5 mm/day
• fast axonal flow = 2-way–> travels along surface of microtubules–> 200-400 mm/day

Question 8

Dif b/t neuroglia of CNS vs PNS

Answer 8

more complex and more numerous

Question 9

astrocytes

Answer 9

CNS

• most numerous one
• anchor neurons/blood vessels
• maintain blood-brain barrier

Question 10

Microglial cells

Answer 10

CNS

• phagocytic
• defensive

Question 11

Ependymal cells

Answer 11

CNS

• line cavities
• secrete CSF
• circulate CSF with cilia

Question 12

Oligodendrocytes

Answer 12

CNS

• have processes that form myelin sheaths around CNS fibers
• reach multiple axons/sections of axons

Question 13

Satellite cells

Answer 13

PNS

• surround neuron cell body
• protect and maintain chemical environment

Question 14

Schwann cell

Answer 14

PNS

• surround fibers and form myelin sheaths
• vital to regenerate damaged peripheral nerve fibers

Question 15

Myelination

Answer 15

• Schwann cells myelinate acons in PNS during fetal dvlpmnt
• Schwann cell cytoplasm and nucleus form outermost layer of neurolemma with inner portion being the myelin sheath
• tube guides growig axons that’re repairing themselves

Question 16

cell bodies vs axons in PNS vs CNS

Answer 16

CNS cell bodies = nucleus
PNS cell bodies = ganglion
CNS axons = tract
PNS axons = nerve