Intro to Nervous System

Question 1

Neuron

Answer 1

Post mitotic (cant divide)
Conduct and transmit electrochemical signals
Dependent on Na/K pump
(ATP is utlilized very quickly, neurons die if no ATP is available)

Question 2

Glial cells

- Function

Answer 2

Mitotic
Function: support cells in n system
(extremely resistant to chemotherapy and radiation)

Question 3

Oligodendrocytes vs Schwann cells

Answer 3

Oligodendrocytes:
- Produce myelin for multiple neurons (CNS)

Schwann cells:

• Maintain myelin in PNS
• One cell myelinates one segment of one axon

Question 4

Myelin sheath

• Function
• Composition

Answer 4

Function: inc speed of electrical neural signals

Composition: layers of lipids. Contain layers of lipids, cholesterol, phospholipids

(surround axon)

Question 5

Ependymal

Answer 5

Line parts of ventricular system
Aid in CSF production
(CSF helps brain float)

Question 6

Tanycytes (type of ependymal)

Answer 6

Function not fully understood

Thought to mediate signaling btn CSF and CNS

Question 7

Astrocyte

- Endfeet

Answer 7

Endfeet form external limiting membrane on brain and SC (glial membrane)

Structural support and helps form BBB

Trauma can disrupt astrocytic footing leading to cerebral edema

Question 8

Astrocyte functions (5)
- Injury

Answer 8

• Ionic buffer: maintain electrolyte buffer
• Produce neurotrophic factors: give neuron GF to inhibit apoptosis
• Contain glial fibrillary acidic protien (GFAP): structural support of astrocyte
• Neurotransmitter removal: remove NTs. Too much would cause a build up of NTs and additional info from the neuron would not be passed
• BBB: prevent viruses, baterial… from crossing into CNS. Everywhere except brainstem
• Injury: Triggers astrogliosis (astrocytic scar)

Question 9

Why do astrocytes contain glycogen granules?

Answer 9

• Maintain ionic buffer
• Prevent apoptosis of neurons (neurotrophic factors)
• Remove neurotransmitters

Question 10

Microglia

- Problem

Answer 10

Phagocytic cells in CNS

Problem: Astrogliosis. Neurons are finicky. Only way microglia get to cells is by secreating proteases which degrade pro which create tunnels.

Question 11

Simple diffusion

Answer 11

Transport depends on solute concentration.

NO ATP

Question 12

Facilitated diffusion vs active transport

Answer 12

Facilitated diffusion:
mediated by channel and carrier PRO
NO ATP
Flow by electrostatic and diffusion

Active transport:
mediated by channel and carrier PRO
ATP
Flow by conc gradient and electric potential (electrochemical gradient)

Question 13

Dendrite (Input region)

Answer 13

Chemical signal converted to electrical
Carries impulses to cell body
Energy is needed to carry signal*

Question 14

Dendritic spines

Answer 14

Can ext or retract
Can undergo pathological alterations

Retrations: stress, hormones, less sleep, tumor

Question 15

Down syndrome vs Alzheimer’s

Answer 15

Down syndrome: Have limited arborization and spines
Have neurons but less arborization (dont have the spines)

Alzheimer’s: Dont have a lot of spines and arbor
Have the fewer neurons resulting in less spines and arbor

Question 16

Stucture (functional) names of neurons

Answer 16

Dendrite (input region)
Soma (perikaryon)
Axon hillock (intergration center)
Axon (conduction region)
Presynaptic terminal (output region) - No microtubules*