Lecture 9: Histology of the Nervous System

Question 1

Ventricular Space

Answer 1

Internal core of CNS, sac filled with CSF, flows into subarachnoid space, lined by ciliated ependymal cells

Question 2

Polarization of Neurons

Answer 2

structurally polarized by axon vs. dendrites; microtubules positive ends towards terminal bouton of axon, negative end towards nucleus

Question 3

Bipolar Neurons

Answer 3

Found in the retina and all cells related to the 8th cranial nerve (auditory)

Question 4

Multipolar neurons

Answer 4

found everywhere

Question 5

unipolar neurons

Answer 5

Found in DRG

Question 6

2 main types of neuron shapes

Answer 6

pyramidal (all have spines) and spiny stellate

Question 7

dendrite spines effected by

Answer 7

experience, learning, memory, cognition, plasticity, hormones and aging

Question 8

amacrine cells

Answer 8

no axon, famously found in retina

Question 9

telodendrons

Answer 9

branching of axons, end in terminal boutons

Question 10

Parts of synapse

Answer 10

presynaptic membrane (of axon, can see vesicles); synaptic cleft; post-synaptic membrane density

Question 11

the neuro-muscular junction

Answer 11

presynaptic membrane very inter-folded with-in the muscle tissue, called junctional folds
Enlarged terminal bouton called end-plate
enlarged synaptic cleft
Synapsing muscle called sole-plate
Differences serve to increase the amount of neuro-transmitter released

Question 12

motor neuron

Answer 12

V. prominent nucleolus, lots of nissl bodies (RER site, needs to make protein for neurotransmitters)
Affected by polio and ALS

Question 13

three types of neuronal cell death

Answer 13

apoptosis (natural/abnormal), necrosis/cytoplasmic (brain trauma), autophagy (auto-immune disease

Question 14

Glia types

Answer 14

astrocytes, oligodendrocytes, microglia

Question 15

Microglia

Answer 15

CNS macrophages, activated by inflammation, can be helpful and harmful

Question 16

Astrocytes

Answer 16

Scavenge neurotransmitters that is leaking, funnel back into neuron; form a lining around the capillary with feet-like processes. All blood vessels in brain covered by astrocyte perivascular end-feet, one astrocyte will cover multiple capillaries

Question 17

oligodendrocytes

Answer 17

Processes of one form myelin sheath for many axons, gaps in myelin sheath create nodes of ranvier, saltatory conduction

Question 18

multiple sclerosis

Answer 18

demyelinating disease of CNS

Question 19

PNS myelination

Answer 19

Supplied by Schwann cells (neurolemmocytes)

Question 20

Schwann cells function

Answer 20

cover all PNS axons, if axon is myelinated will wrap around axon many times creating insulating myelin sheath, nodes of ranvier not insulated but still covered by cell processes

Question 21

neurolemmocytes

Answer 21

another name for schwann cells

Question 22

PNS connective tissue layers

Answer 22

PNS cell –> Schwann cell –> Endoneurium (CT) –> many neurons make up one fasicle/fasiculus –>perineural epithelium –> perineurium (fibrous CT)–> many fasicles make up nerve trunk –> epineurium