Nervous Tissue Anatomy

Question 1

what is the enteric neural system?

Answer 1

innervation of the gut

Question 2

what is the autonomic nervous system?

Answer 2

having to do with the sympathetic and parasympathetic system

Question 3

what is the somatic nervous system?

Answer 3

having to do with the somatic motor neurons

Question 4

what is the soma?

Answer 4

cell body of the neuron

Question 5

what is the telodendria?

Answer 5

branching of the axon with the end-bulb

Question 6

what is an axon collateral?

Answer 6

axon that juts off the major axon

Question 7

what is the axon helliock, initial segment or trigger zone?

Answer 7

area where the first action potential will be generated

-where body of neuron and axon meet

Question 8

what is the graded potential?

Answer 8

areas on the dendrites

Question 9

what is the myelin sheath?

Answer 9

surrounds the axon

Question 10

what do Schwann cells do?

Answer 10

lay down myelin only located in the peripheral nervous system
-one Schwann cell: one node of myelin

Question 11

what do oligodendrocytes do?

Answer 11

lay down myelin in CNS

-can coat many cells

Question 12

what are the nodes of Ranvier

Answer 12

spaces in between Schwann cells where action potentials jump to
-sodium and potassium voltage gated channels are here (not underneath the myelin)

Question 13

what kind of ion channels do nerve cells have?

Answer 13

voltage-gated sodium and potassium channels

Question 14

what is the axolemma?

Answer 14

the plasma membrane of an axon

Question 15

what is the neurolemma?

Answer 15

the plasma membrane of the Schwann cells

Question 16

what are missile substance?

Answer 16

ribosomes within neuron cells

Question 17

do CNS neurons regrow?

Answer 17

no other cells have to take over their function

-don’t have centrioles (they don’t divide)

Question 18

what is a neuroglial cell?

Answer 18

small, tiny cell, more abundant

Question 19

what are the 4 types of CNS neural cells?

Answer 19

astrocytes
oligodendrocyte
ependymal
microglial

Question 20

what are the 2 types of PNS neural cells?

Answer 20

Schwann cell

satellite cell

Question 21

what are the 3 types of ligands in the body? (substance that binds to a receptor to initiate change)

Answer 21

neurotransmitters
hormones
drugs

Question 22

what kind of ion channels do dendrites have?

Answer 22

ligand (chemically) gated

Question 23

what kind of ion channels do axons have?

Answer 23

voltage gated

Question 24

what is special about neurons?

Answer 24

multitude of neuron transmitters

multitude of ion channels

Question 25

what ion channels are present on the axon?

Answer 25

sodium and potassium exlusively

Question 26

what is the normal picture of neurons

Answer 26

hundreds and thousands of neural cells touching one another

Question 27

what is the main purpose of the dendrite?

Answer 27

increase receptive surface area of the neural cell

Question 28

what does anterograde mean?

Answer 28

moving neurotransmitter from cell body to synaptic end ball - uses kinesin - nutrients - enzymes - mitochondria

Question 29

which type of protein moves neurotransmitter from synaptic ball to cell body (retrograde)?

Answer 29

dynein - may send recycled membrane vesicles - growth factors - other chemicals - some diseases

Question 30

alzheimers mechanism

Answer 30

microtubules within neurons get tangles up and stop working

Question 31

what is afferent?

Answer 31

into the CNS (sensory)

Question 32

what is efferent?

Answer 32

away from the CNS (motor)

Question 33

what type of neurons are unipolar?

Answer 33

``` sensory neurons (most sensory are unipolar) -cell body is offset from axon ```

Question 34

what are interneurons?

Answer 34

transfer sensory information to CNS (have short axons)

Question 35

what is important about motor neurons?

Answer 35

cell body is located inside the CNS | usually multipolar

Question 36

where are bipolar neurons?

Answer 36

special senses (retina, olfactory)

Question 37

where in the brain are the Purkinge cells?

Answer 37

cerebellum | largest neuron in the entire CNS

Question 38

where are pyramidal cells found?

Answer 38

frontal lobe of brain in the precentral gyrus

Question 39

corticospinal pathway

Answer 39

from frontal lobe to body

Question 40

nociceptor

Answer 40

pain sensor

Question 41

spinothalamic track

Answer 41

in spinal cord, cross and receives information on the opposite side of brain where injury occurs -parietal, post sensory cortex

Question 42

what does the astrocyte do?

Answer 42

it is the most abundant of the glial cells helps the neuron get the nutrients that it needs -good extracellular environment -remove waste -caretaker -BBB -fetal development

Question 43

components of BBB

Answer 43

1. tight junctions 2. thick basement membrane in capillaries 3. foot processes of astrocytes sitting on top of the capillaries

Question 44

BBB works against us in which situations?

Answer 44

chemo | antibiotics

Question 45

where do primary brain tumors originate from?

Answer 45

glial cells (neurons can't divide)

Question 46

most common type of brain tumor

Answer 46

astrocytoma

Question 47

what are the two types of astrocytes?

Answer 47

``` protoplasmic -present in gray matter -many short branching processes fibrous -present in white matter -many long unbranched processes ```

Question 48

what is the pia mater?

Answer 48

inner layer of meninges sitting right on the brain

Question 49

what does a microglia do (spider-like cells)?

Answer 49

``` phagocytic function (remove cellular debris) (brain has no lymphatic system other than these cells) ```

Question 50

what do ependymal cells do?

Answer 50

line the ventricular system of brain and central canal of the spinal cord - cuboidal/columnar have microvilli, cilia and tight junctions - produces and maintain the circulation of the CSF

Question 51

what do oligodendrocytes do?

Answer 51

synthesize and maintain the myelin sheath of axons in the CNS

Question 52

what is white matter?

Answer 52

nervous tissue that is myelinated

Question 53

what is gray matter?

Answer 53

nervous tissue that is non-myelinated

Question 54

how does myelin impact speed of conduction?

Answer 54

``` unmyelinated = slower myelinated = faster ```

Question 55

how does size of neural cell impact speed?

Answer 55

``` wider = faster thinner = slower ```

Question 56

ganglion

Answer 56

collection of nerve cell bodies in the PNS

Question 57

what type of cell sits on top of the ganglion?

Answer 57

satellite cells

Question 58

what do satellite cells do?

Answer 58

regulate the exchange of materials between the neurons and the interstital fluid

Question 59

how much myelin do Schwann cells lay down?

Answer 59

specific ratio of axon diameter: myelin diameter

Question 60

how much do axons regrow if peripheral nerve is damaged?

Answer 60

1mm/day

Question 61

how many neurons are killed off when a fetus develops?

Answer 61

50-70% of the original ones

Question 62

where do motor neurons exit SC?

Answer 62

ventral root

Question 63

where do sensory neurons enter SC?

Answer 63

dorsal root