nervous system histology

Question 1

three functions of nervous system

Answer 1

gathers information or sensory input. to detect internal or external stimuli

2. integration: it processes and interprets sensory input and decides what action should be taken (association neurons or interneurons)
3. motor output activating effector organs

Question 2

how many spinal nerves and how many cranial nerves

Answer 2

31, 12

Question 3

a nerve is a collection of ____ i.e. process of a neuron that can generate ____

Answer 3

axons, action potentials

Question 4

neurons are ___ cells that can produce electrical signals

Answer 4

excitable

Question 5

action potential

Answer 5

rapid changes in electrical potential of cells created across plasma membrane

Question 6

neuroglia or glia

Answer 6

smaller neurons, supporting cells. important for electrical Mediate or metabolic exchange between vascular system and neurons

Question 7

neuroglia and glia do NOT

Answer 7

generate action potential

Question 8

are nerve cells or neuroglia are more numerous

Answer 8

neuroglia (they can multiply and divide)

Question 9

special characteristics of neurons

Answer 9

1. extreme longevity (100 yrs)
2. amitotic (lose ability to divide can’t be replaces)
3. high metabolic rate (need large supply of O2 and glucose; die in minute without o2)

Question 10

perikaryon

Answer 10

neuron cell body

Question 11

can you have multiple dendrites or axons

Answer 11

dendrites

Question 12

main function of the perikaryon

Answer 12

biosynthetic center of the neuron; no CENTRIOLES because its amitotic; no action potential

Question 13

nissl bodies

Answer 13

free ribosomes that clump together

Question 14

what helps maintain the shape of neurons

Answer 14

microtubules and neurofibrils

Question 15

axon hillock

Answer 15

part of cell body where axon attaches; no organelles

Question 16

dendrite function

Answer 16

main receptive or main input regions. lots of surface area and greatly branched

Question 17

dendrites are always

Answer 17

unmyelinated with no action potential

Question 18

all organelles except ___ extend into dendrites

Answer 18

Golgi

Question 19

secretory portion of the neuron

Answer 19

axon hillocks

Question 20

anterograde transport

Answer 20

substances move from cell body towards axon terminal

Question 21

retrograde transport

Answer 21

substance move from axon terminal towards the cell body

Question 22

what releases neurotransmitters

Answer 22

axon terminal or terminal boutines

Question 23

the cell body of a neuron is never

Answer 23

mylenated

Question 24

multipolar neurons

Answer 24

3 or more processes

Question 25

bipolar nuerons

Answer 25

2 processes

Question 26

unipolar neurons

Answer 26

1 process

Question 27

3 types of neurons based on function

Answer 27

1. sensory or afferent neurons 2. motor or efferent neurons 3. interneurons or association neurons- found between motor and sensory

Question 28

trigger zone

Answer 28

nerve impulses generated at area

Question 29

rarest type of neuron in human body

Answer 29

bipolar

Question 30

all bipolar neurons are

Answer 30

sensory neurons (some special sensory)

Question 31

most unipolar neurons are

Answer 31

sensory neurons

Question 32

postsynaptic neuron

Answer 32

neuron carrying impulse away from synapse (can be an effector cell)

Question 33

chemical synapses are released into the ____ while electrical synapses are sent directly to the adjacent cell via ____

Answer 33

synaptic cleft, gap junctions

Question 34

synaptic cleft is filled with

Answer 34

interstitial fluis, so action potential can't babe conducted

Question 35

which synapse type is faster

Answer 35

electrical because chemical synapses have to be changed into electrical

Question 36

post synaptic neurons contain

Answer 36

ligand gated receptors to which the neurotransmitter binds

Question 37

nerve impulse depolarization causes`

Answer 37

voltage gated CA2 channels to open

Question 38

3 ways neurotransmitters are removed from postsynaptic receptors

Answer 38

degradation by enzymes, reuptake by astrocytes or presynaptic terminal, diffusion away from synapse

Question 39

6 types of neuroglia (4 CNS, 2 PNS)

Answer 39

1. astrocyte 2. microglia cell 3. ependymal cells 4. oligodendrocyte 5. schwann cells 6. satellite cells

Question 40

which cells produce myelin

Answer 40

oligodendrocytes and schwann cells

Question 41

intranodal segment

Answer 41

oligodendrocytes produce one sheet of myelin for multiple neurons`

Question 42

predominant glial cells are found in

Answer 42

white matter

Question 43

oligodendrocyte histology

Answer 43

unstained cytoplasm and dark nucleus. usually in rows

Question 44

largest nueroglia

Answer 44

astrocyte

Question 45

astrocytes are found in

Answer 45

white matter and grey matter

Question 46

major function of astrocytes

Answer 46

controlling the ionic environment of neurons | other: get rid of excess neurotransmitters, form cellular scar tissue, assist in CNS embryo development

Question 47

perivascular feet

Answer 47

part of astrocyte that cover capillary endothelia cells and contribute to the blood brain barrier

Question 48

ependymal cells

Answer 48

low columnar or cuboidal. line spaces found in brain and spinal cord.

Question 49

ependymal cells have

Answer 49

cilia that extends into places with cerebral spinal fluid; helps CSF move

Question 50

ependymal cells are modified in

Answer 50

the ventricles to become the choroid plexus

Question 51

cells that line the central canal

Answer 51

ependymal cells

Question 52

microglia are distributed in

Answer 52

white and grey matter evenly

Question 53

microglia histology

Answer 53

short irregular processes with spikes, nuclei are elongated

Question 54

major function of microglia

Answer 54

analyze cells for damaged tissues ; major mechanism for immune defense

Question 55

neuroglia that can migrate

Answer 55

microglia

Question 56

neuroglia that originates form blood monocytes

Answer 56

microglia

Question 57

what morphology do microglia assume when activated

Answer 57

macrophages; become phagocytotic and antigen presenting

Question 58

satellite cell

Answer 58

create covering layer over neuronal bodies in the PNS ganglia

Question 59

white matter is composed of primarily ____ while gray matter is composed of ____

Answer 59

myelinated axons with some neuroglia, unmylennated axons with nissl bodies

Question 60

myelinated fibers conduct impulses ____ while unmyelinated fibers conduct _____

Answer 60

rapidly, slowly

Question 61

continuous conduction

Answer 61

ummylenated axons

Question 62

saltatory conduction

Answer 62

mylenated axons

Question 63

action potential has to be regenerated at

Answer 63

nodes of ranvier