Neuroglial Cells

Question 1

what are the functions of neuroglia

Answer 1

regulate flow of CSF, monitor synapses, scavenge neurotransmitters, release gliotransmitter

Question 2

what are the neuroglia of the CNS

Answer 2

astrocytes, olgiodendrocytes, microglia, ependymal cells

Question 3

what are the neuroglia of the PNS

Answer 3

schwann cells

Question 4

write about astrocytes

Answer 4

these give structural and metabolic support to neurons. they are the largest neuroglial cell and have two distinct types: protoplasmic and fibrous astrocytes which make up parts of the grey and white matter of CNS respectively

Question 5

write a short notes about fibrous astrocytes

Answer 5

have a euchromatic cytoplasm witha few organelles. have long branched extensions, and are typically involved with the pia mater and blood vessels as they assist in maintaining the blood-brain-barrier

Question 6

write a note on olgiodendrocytes

Answer 6

these function in electrical insulation + myelin production in CNS. they are located in grey and white matter of CNS. Have two subdivisions interfasicular olgiodendrocytes and satellite olgiodendryocytes

Question 7

what are interfascicular olgiodendrocytes

Answer 7

these are located in rows beside bundles of axons. these produce and maintain myelin on axons of CNS. a single olgiodendrocyte forms a number of processes (extensions). they wrap a small region called an internode.

Question 8

what are satellite olgiodendrocytes

Answer 8

they are closely applied to cell bodies of large neurons. are only in grey matter and function is not well understood

Question 9

write a note on microglial cells

Answer 9

are part of the mononuclear phagocyte system. are scattered around the CNS. Secrete interferon gamma when activated, and also recruit T-lymphocytes

Question 10

write a note on ependymal cells

Answer 10

these are low columnar epi cells which line ventricles of the brain and central canal of spinal cord. can sometimes be ciliated, and facilitate movement of CSF

Question 11

write a note on schwann cells

Answer 11

form myelinated and unmyelinated coverings over axons in PNS. they are flattened cells, and myelin is the plasmalemma of the cells which is organised in rings around the axon. this permits salutatory conduction.

Question 12

what are nodes of ranvier

Answer 12

interruptions in myelin sheath

Question 13

what are peripheral nerves

Answer 13

are bundles or fascicles located outside the CNS. Can be mixed nerves, i.e sensory and motor fibres

Question 14

define epineurium, perineurium and endoneurium

Answer 14

outermost, middle and inner layers in peripheral nerves