lecture 10 - organization of NS

Question 1

describe the parts of the neuron

Answer 1

cell body:
- has nucleus

dendrites:
- region of input (collects info or signals)
- cytoplasmic extensions

axon:
- output regions where AP is transmitted

Question 2

what are neuroglial cells?

Answer 2

• non-neural cells = cant produce AP
• support and protect neurons

Question 3

describe the parts of the neuron from dendrite to presynaptic terminal

Answer 3

written down

Question 4

what is axonal transport and how does it work

Answer 4

vesicles transport neurotransmitters in the presynaptic terminal and get released at the end of the axon and send signal to target tissue

Question 5

what is the role of the vesicles

Answer 5

to release neurotransmitters to stimulate or inhibit the postsynaptic cell / target tissue

Question 6

how can axonal transport allow for disease transmission?

Answer 6

b/c the vesicles can move up and down the axon transporting the neurotransmitter and the disease can get to cell bodies and to CNS

Question 7

what are the different functional classifications of neurons

Answer 7

sensory/afferent
- AP towards CNS

motor/efferent
- AP away from CNS

interneurons/association neurons
- withing CNS from one neuron to another
- make decisions on if we make a motor response or not from sensory info

Question 8

what are the different structural classifications of neurons

Answer 8

multipolar
many dendrites, single axon

bipolar:
1 dendrite, 1 axon
in sensory organs

unipolar / pseudo-unipolar
single process extending from cell body
- divides into 2 branches and dendrite works as sensory receptor

Question 9

what are the supporting cells of the NS?

Answer 9

neuroglia - glue of neurons that help support and protect cells between or within space of neurons
4 neuroglial cell types in CNS
2 types in PNS

Question 10

what are astrocytes? CNS

Answer 10

• star shaped biggest cells
• the cytoplasmic ext. forms foot processes which releases chemicals to form tight junctions between endothelial cells of capillaries

Question 11

what is the blood brain barrier (astrocytes)?

Answer 11

job of the tight junctions is to regulate the movement of substances into and out of the Nervous tissue of brain and spinal cord

–> this creates a blood brain barrier which highly regulates anything getting into nervous tissue (protect against toxic substances)

Question 12

what are ependymal cells? CNS

Answer 12

cells that line the ventricles of the brain and central canal of spinal cord
- they help form the choroid plexus which produces CSF
- ciliated which allows it to move CSF through venticles

Question 13

what are microglia cells? CNS

Answer 13

theyre speciallized macrophages in the CNS who have a protective mechanism which digests dying tissues, microorganisms, foreign substances that invade CNS via phagocytic - inflmmation (wraps around thing and engulfs it)

Question 14

what are oligodendrocytes? CNS

Answer 14

cytoplasmic extensions that surround axons and form myelin sheaths around parts of several axons

Question 15

what are schwann cells? PNS

Answer 15

wraps around axons many times and causes cytoplasm and nucleus to be pushed towards the outside

forms myelin sheath around a portion of ONE axon

Question 16

what are satellite cells? PNS

Answer 16

surround neuron cell bodies in ganglia (protect and support) and provides nutrients to cell body

Question 17

myelinated vs unmyelinated axons

Answer 17

myelin protects and insulates axons from one another

myelinated axons conduct signals more rapidly vs unmyelinated

Question 18

what is a tract

Answer 18

bundle of myelinated axons in CNS

Question 19

white matter vs grey matter

Answer 19

white:
myelinated axons, nerve tract propagates AP from one area to another

grey:
unmyelinated axons, cell bodies, dendrites and neuroglia.
- where all the decision making is happening

Question 20

white and grey matter in CNS

Answer 20

spinal cord:
white = outer, grey = inner

brain:
white = inner, grey = outer