Brain And NS 2

Question 1

Four main functions of glial cells

Answer 1

Support and hold neurones in place, nourishment, electrically insulate neurones, protect from pathogens

Question 2

Astrocyes

Answer 2

Star shaped glial cells, contribute to blood brain barrier, role in inflammatory response in brain

Question 3

Blood brain barrier

Answer 3

Created by the fact that endothelial cells fit well together, making capillary cell membranes permeable to fat-soluble substances

Question 4

Schwann cells (PNS)

Answer 4

Rich in lipids, produce myelin,wrap around exons to provide myelin sheath

Question 5

Myelin sheath

Answer 5

Provides electrical insulation, enhances speed of electrical conductance, termed saltatory conduction

Question 6

Oligodendrocytes (CNS)

Answer 6

Myelin-producing, highly branched, contact several axons and coat in myelin

Question 7

Microglia (CNS)

Answer 7

Small immune cells, act as phagocytes for debris in CNS, primary immune defence, work closely with astrocytes

Question 8

Multiple sclerosis

Answer 8

Immune system destroys myelin sheath, reducing speed and success of nerve conduction, symptoms like pins and needles, loss of motor function, and visual disturbance

Question 9

CNS myelination

Answer 9

Single oligodendrocyte myelinates many axons

Question 10

PNS myelination

Answer 10

Single axon has many myelinating Schwann cells

Question 11

Body response to CNS damage

Answer 11

Astrocytes divide and become reactive, invading injury site and attracting microglia, damage is permanent and debilitating due to barrier to axon growth

Question 12

PNS damage

Answer 12

Ca repair and regenerate over time as PNS contains fewer specialised support cells