CTO Nerve tissue

Question 1

Nissl substance

Answer 1

coarse clumps of ER in cytoplasm of neurons

Question 2

neuron morphology (3)

Answer 2

multipolar, bipolar, unipolar

Question 3

axonal cytoplasm components

Answer 3

lack of nissl substance, elaborate cytoskeletal array (neurofilaments, microtubules, actin) for structural support and delivery of materials

Question 4

Motor proteins role in neurons

Answer 4

kinesins for anterograde transport in axon, dyneins for retrograde transport in axon

Question 5

Action potential

Answer 5

rapid reversal of polarization of nerve cell membrane through opening of voltage gated Na-channels

Question 6

Absolute refractory period

Answer 6

time after potential during which piece of membrane cannot be depolarized again

Question 7

neuromodulator

Answer 7

transmitter that binds to ligand-gated ion channel and effects ease of opening or works through second messsenger systems

Question 8

2 types of neurotransmitter effect on receptors in post-synaptic membranes

Answer 8

1. receptor acts as an ion channel OR 2. receptor acts as part of a transmembrane protein w/ enzyme effects on postsynaptic neuron (i.e. metabotrophic receptor)

Question 9

metabotrophic receptors

Answer 9

receptor that acts as a part of a transmembrane protein w/ enzyme effects on postsynaptic neuron, works through second messenger systems; can have prolonged effects

Question 10

Pathways for metabolite recycling by presynaptic element

Answer 10

1. enzymatic breakdown, 2. diffusion, 3. reuptake into presynaptic nerve terminal

Question 11

3 types of peripheral nerves

Answer 11

1. motor 2. sensory 3. autonomic

Question 12

myelin sheath

Answer 12

wrap of cell membrane surrounding nerve fibers to increase speed of conduction and provide insulation

Question 13

function of myelin

Answer 13

increase spead of conduction, result from action of specialized cells

Question 14

schwann cells

Answer 14

in PNS, myelin results from schwann cells

Question 15

oligodendrocytes

Answer 15

in CNS, myelin results from oligodendrocytes

Question 16

schwann cell membrane - important characteristic

Answer 16

membranes contain glycoproteins that recognize other glycoproteins on surface of axons

Question 17

Schmidt-Lanterman clefts

Answer 17

places in myelin sheath where protoplasm is not fully extruded to periphery during schwann cell myelination

Question 18

Nodes of ranvier

Answer 18

gaps b/t adjacent schwann cells where voltage-gated sodium channels are concentrated; action potential regenerated here; pinched appearance

Question 19

saltatory conduction

Answer 19

“jumping conduction”, action potential passes from node of Ranvier –> next node of Ranvier

Question 20

What determines the speed of conduction of the axon?

Answer 20

distance b/t nodes of ranvier: long distance –> greater spead

Question 21

Epinerium

Answer 21

surrounds entire peripheral nerve

Question 22

perineurium

Answer 22

surrounds bundles of fascicles of nerve fibers

Question 23

ganglia

Answer 23

collection of nerve cell bodies outside of central nervous system

Question 24

Two types of ganglia

Answer 24

1. autonomic ganglia 2. sensory ganglia

Question 25

sensory ganglia

Answer 25

cellbodies of peudounipolar cells

Question 26

autonomic ganglia

Answer 26

part of sympathetic or parasympathetic nervous system

Question 27

satellite cells

Answer 27

cells surrounding ganglia; involved in maintaining proper environment around ganglion cells

Question 28

free nerve ending

Answer 28

simplest type of peripheral sensory nerve ending; mostly pain or temperature sensors

Question 29

Meissner's corpuscles

Answer 29

connective tissue in subcutaneous connective tissue appearing in dermis beneath the skin

Question 30

Pacinian corpuscle

Answer 30

layers of connective tissue circumferentially arranged around a nerve ending

Question 31

Glial types in CNS

Answer 31

macroglia, microglia

Question 32

microglia

Answer 32

derived from mesoderm/same cell line as macrophages, phagocytic, but migrate to nervous system early in life and remain there, proliferate in certain pathological states

Question 33

astrocytes

Answer 33

maintain interstitial environment (ions within nervous system, metabolize neurotransmitters, manufacture growth factors for supprot of neurons); contact brain surface under pia mater, contact blood vessels within brain via foot processes --> induce formation of endothelium BBB

Question 34

Oligodendrocytes

Answer 34

responsible for CNS myelination; have multiple processes -> can myelinate multiple axons

Question 35

macroglia origin

Answer 35

neural epithelium --> glioblasts--> macroglia (3 types)

Question 36

blood-brain barrier

Answer 36

endothelia cells on BBB have tight intercellular junctions and few pinocytotic vesicles; capillaries are highly selective to permability

Question 37

blood-CSF barrier

Answer 37

capillaries of choroid plexus are fenestrated and highly permeable; choroid epithelium has tight junctions and provides barrier b/t blood and CSF

Question 38

meninges

Answer 38

outside --> inside: dura mater --> arachnoid --> pia mater

Question 39

Formation of CSF

Answer 39

made my choroid plexus, stays in subarachnoid space

Question 40

Difference b/t schwann cells and oligodendrocytes

Answer 40

schwann cells become myelination in PNS; oligodendrocytes can myelinate multiple axons; proteins oligodendrocyte membrane are different than on schwann cells, so can be differently affected by disease

Question 41

choroid plexus

Answer 41

makes CSF; modified ependymal cells that form the blood-CSF barrier; form tight junctions that do not allow substances from capillaries to pass into CSF in certain areas of the ventricle w/ blood vessels

Question 42

types of macroglia

Answer 42

1. astrocyes 2. oligodendrocytes 3. ependymal

Question 43

Formation of BBB

Answer 43

Astrocytic foot processes contact capillaries in brain --> induce epithelium to change to produce BBB (endothelial cells develop tight intercellular barriers)

Question 44

neurulation

Answer 44

notochord induces formation of neural tube, which makes CNS (incl. motor nerve fibers and preganglionic autonomic nerve fibers) , neural crest cells make PNS (incl. Schwann cells, sensory nerves, postganglionic autonomic nerves)

Question 45

axonal transport speed

Answer 45

slow & fast: based on bidning strenght of particular substance to kinesins or dyneins (stronger binding --> fall off less/quicker movement)

Question 46

two factors contributing to speed of an axon

Answer 46

diameter of axon and thickness of myelin sheath

Question 47

endoneurium

Answer 47

encases individual axons/nerve fibers