Cto - Nervous Tissue

Front 1

which part of the embryo are both neurons and glial cells derived?

Back 1

neuroepithelium

Front 2

what is another word for cell processes in neurons?

Back 2

neurites

Front 3

what is the name for the RER found in neurons?

Back 3

Nissl substances

Front 4

why is lipofuscin often found in neurons?

Back 4

because they are long-lived and do not regenerate

Front 5

what is the point on the axon where action potentials are generated?

Back 5

axon hillock

Front 6

what is the term for branching of axons?

Back 6

terminal arborization

Front 7

what characterizes the cytoplasm of axons?

Back 7

lack of Nissl substance and presence of elaborate cytoskeletal array

Front 8

which two microtubule-associated proteins are primarily responsible for transport of proteins up and down axons?

Back 8

dynein (toward soma) and kinesin (toward axon terminal)

Hint 8

None

Front 9

what is the name for a synapse between an axon and a dendrite? Between an axon and a cell body?

Back 9

axodendritic synapse; axosomatic synapse

Front 10

which organelles are abundant in the axon terminal?

Back 10

mitrochondria, SER, endosomes

Front 11

why does the presynaptic membrane of the axon bouton appear to be thickened when viewed with an EM?

Back 11

due to presence of many specialized proteins involved in docking and release of synaptic vesicles.

Hint 11

None

Front 12

the depolarization of nerve cells in action potentials is largely due to which ion channels?

Back 12

voltage-gated Na+ channels

Front 13

which phenomenon prevents the action potential from doubling back on itself in the axon?

Back 13

absolute refractory period

Front 14

depolarization of the axon terminal leads to influx of which ion?

Back 14

Calcium

Front 15

to what do neurotransmitters bind once released into the synaptic cleft?

Back 15

specific receptors on the post-synaptic membrane

Front 16

receptors in post-synaptic membrane have which 2 functions?

Back 16

ion channels or enzymatic action

Front 17

which, ion channels or enzymatic receptors, have second messenger mechanisms which create a prolonged effect?

Back 17

enzymatic receptors

Front 18

are ion channels in post-synaptic membranes normally excitatory or inhibitory?

Back 18

either, depending on which ions are allowed through

Front 19

what is the term which refers to a transmitter that either binds to the ligand-gated ion channel and affects its ease of opening or that works through the second messenger system?

Back 19

neuromodulator

Front 20

what are the 3 ways by which neurotransmitters are deactivated?

Back 20

1) enzymatic breakdown, 2) diffusion, 3) reuptake into the presynaotic nerve terminal

Front 21

does the activity of a neurotransmitter depend more on the identity of the NT or the receptor?

Back 21

receptor

Front 22

myelination of axons is performed by which cells in the PNS? In the CNS?

Back 22

Schwann cells; oligodendrocytes

Front 23

how do Schwann cells recognize axons?

Back 23

via glycoproteins on Schwann cells and axons

Front 24

how is the cytoplasm in Schwann cells attenuated in wrapping around axons?

Back 24

via hydrogen bonding on inner surface of Schwann cell membranes

Hint 24

None

Front 25

what is the name for the regions of Schwann cells where cytoplasm has not been completely attenuated?

Back 25

Schmidt-Lanterman clefts

Front 26

how do nutrients and ions cross the many layers of myelin?

Back 26

via gap junctions

Front 27

what is the term used for the gaps between adjacent Schwann cells? What is concentrated in these gaps?

Back 27

Nodes of Ranvier; ion channels

Front 28

what is the name for the conduction of action potentials down an axon, from one Node of Ranvier to another?

Back 28

saltatory conduction

Front 29

if the internodal distance on axons is increased, does the speed of conduction increase or decrease?

Back 29

increase

Front 30

what is the name of the connective tissue that covers the individual axons? Fasicles? Entire nerve?

Back 30

endoneurium; perineurium, epineurium

Front 31

why do peripheral nerves have a wavy appearance in cross-sections?

Back 31

so they can stretch without breaking

Front 32

what is the name for the cells which surround ganglia? What is their function?

Back 32

satellite cells; to maintain the proper environment around the ganglion cells

Front 33

what is the name of the simplest peripheral sensory nerve ending? What do they normally detect?

Back 33

free nerve endings; pain or temperature

Hint 33

None

Front 34

which specialized sensory nerve ending winds around certain specialized connective tissue cells that distribute force to the nerve fiber?

Back 34

Meissner's corpuscles

Front 35

which specialized sensory nerve ending has layers of connective tissue circumferentially arranged around a nerve ending? What do these detect?

Back 35

Pacinian corpuscle; deep pressure and vibration

Front 36

how many axons are there per muscle fiber?

Back 36

1

Front 37

what is the primary function of glial cells?

Back 37

to support and protect the neurons of the CNS

Front 38

what are the two main categories of glial cells?

Back 38

microglia and macroglia

Front 39

from what do macroglia arise? Microglia?

Back 39

neural epithelium via glioblasts; monocytes

Front 40

what important function do astrocytes perform in neurons?

Back 40

maintain the interstitial environment, including proper levels of ions within the nervous system.

Front 41

which macroglial cell is responsible for metabolizing neurotransmitters and manufacturing growth factors for support of neurons?

Back 41

astrocytes

Front 42

which macroglial cells touch the surface of the brain underneath the pia mater?

Back 42

astrocytes

Front 43

which macroglial cells contact all blood vessels within the brain via foot processes that induce the formation of an epithelium that is highly specialized? What is the name for this epithelium with many tight junctions and few pinocytotic vesicles?

Back 43

astrocytes; blood-brain barrier

Front 44

what is the major difference in function between Schwann cells and oligodendrocytes?

Back 44

oligodendrocytes have many processes and each one myelinates several axons whereas Schwann cells myelinate one axon per cell

Front 45

are the proteins in Schwann cells and oligodendrocytes identical?

Back 45

no, some disease differentially target Schwann cells or oligodendrocytes

Front 46

which type of cells line the ventricles and central canal of the spinal cord?

Back 46

ependymal cells

Front 47

in the certain areas of the ventricles, which cells have tight junctions and do not allow substances from fenestrated capillaries to pass easily into cerebrospinal fluid? What is the name for these regions? For the barrier?

Back 47

ependymal cells; choroid plexus; blood-CSF barrier

Front 48

which of the glial cells are phagocytotic?

Back 48

microglia

Front 49

from which germ cell layer do microglia arise?

Back 49

mesoderm

Front 50

what is the name for an axon branch that does not occur near the axon terminal?

Back 50

collateral branch

Front 51

what is the name of the intermediate filaments that compose the structural support for the axons?

Back 51

neurofilaments

Front 52

Schwann cells are derived from which part of the embryo?

Back 52

neural crest cells

Front 53

what is the name for the part of the Schwann cell that myelinates the axon?

Back 53

neurolemma

Front 54

what is the name for the structure in the ventricular system which produces CSF?

Back 54

choroid plexus