Glia

Question 1

CNS contains

Answer 1

• brain

- spinal cord

Question 2

PNS contains

Answer 2

• afferent division

- efferent divison

Question 3

afferent division

Answer 3

sensory

Question 4

afferent contains

Answer 4

cranial nerves

Question 5

afferent means

Answer 5

going into

Question 6

efferent division

Answer 6

motor

Question 7

efferent contains

Answer 7

spinal nerves

Question 8

efferent means

Answer 8

exiting

Question 9

neurons

Answer 9

“functional unit’ of nervous system

Question 10

glia (neuroglia)

Answer 10

“nerve glue”

- supports cells

Question 11

glia functions/features

Answer 11

• > 90% of cells in CNS –> 50% by volume
• surround neurons and physically and metabolically support them
• mitotic

Question 12

glia different from neurons

Answer 12

1. no axons
2. local potentials
3. electrical (gap) junctions
4. RMP more negative
   - -> -90 mV = more permeable to K+

Question 13

CNS glia cells:

Answer 13

• astrocytes
• oligodendrocytes
• microglia
• ependymal cells

Question 14

astrocytes

Answer 14

most abundant

Question 15

astrocytes function

Answer 15

1. form blood brain barrier (BBB)
2. nutrient and waste transfer –> require ECF
3. form scaffolding

Question 16

oligodendrocytes function

Answer 16

form myelin sheath around CNS axons (about 40 axons per cell)

Question 17

microglia

Answer 17

macrophages of CNS

- non-neuronal precursor —> come from bone marrow

Question 18

microglia function

Answer 18

clean up cellular debris and bacteria

Question 19

ependymal cells function

Answer 19

• line ventricles of CNS

- produce cerebrospinal fluid (CSF)

Question 20

PNS glia cells:

Answer 20

Schwann cells

Question 21

Schwann cells function

Answer 21

form myelin sheath around axons in PNS –> only one axon per Schwann cell

Question 22

myelin

Answer 22

• 80% lipid

- 20% protein

Question 23

myelin function

Answer 23

insulates axon to increase conduction velocity

• alters cable properties of neuron
• decreases Cm and increases Rm