Spinal Cord

Question 1

what is the main function of the myelin sheath

Answer 1

protect and insulate axons

Question 2

what happens if myelin sheath is damaged

Answer 2

transmission of impulses slowed down eg MS

Question 3

in CNS myelination is by what cells

Answer 3

oligodendrocytes

Question 4

in PNS myelination is by what cells

Answer 4

schwann cells

Question 5

when does myelination start and end

Answer 5

start- 4th month intrauterine life
end- 2-3 yrs

Question 6

types of neuroglia in CNS

Answer 6

Astrocytes, oligodendrocytes,
ependymal cells & microglia

Question 7

function of astrocytes

Answer 7

Supply of nutrients to neurons and removes excess neurotransmitters
Maintains appropriate balance of Ca2+and K+ ions
Aids formation of the blood-brain barrier.

Question 8

function of oligodendrocytes

Answer 8

Myelinate the axons in the CNS

Question 9

function of ependymal cells

Answer 9

Production of cerebrospinal fluid (CSF).
Aids circulation of cerebrospinal fluid (CSF).

Question 10

function of microglia cells

Answer 10

Protects CNS by removing cell debris, wastes and pathogens via phagocytosis

Question 11

what are the two types of neuroglia in the PNS and its functions

Answer 11

1. Schwann cells
   * Myelinate the axons in the PNS, since myelinated nerves conduct impulses more quickly
   * Helps in regeneration of axons in the PNS.
2. Satellite cells – regulate nutrient and neurotransmitter levels around neurons in ganglia