Nervous Tissue Histology

Question 1

what are the 3 functions of the nervous system

Answer 1

1 - sensory input
2 - motor output
3 - processing and integration

Question 2

what is a collection of axons called in the nervous system

Answer 2

nerve

Question 3

what are the 2 basic types of cells found in nervous tissue

Answer 3

• neurons/nerve cells

- glia/neuroglia/supporting cells

Question 4

which basic cells of the nervous system are the excitable cells

Answer 4

neurons

Question 5

which are more abundant in the nervous system, neurons or glia cells

Answer 5

glia cells (can divide/multiply)

Question 6

what are the 3 special characteritics of neurons

Answer 6

longevity
amitotic
high metabolic rate

Question 7

clumps of rough ER and ribosomes found in the cell body

Answer 7

Nissl bodies

Question 8

what is a perikaryon and what is its main function

Answer 8

neuron cell body, its the biosynthetic control center of nuueron

Question 9

in a neuron, what parts of the basic structure is/are myelinated

Answer 9

axon =myelin

dentrite and cell body = unmyelinated

Question 10

what is a axon terminal

Answer 10

storage area of nerve transmitters, its the secretory portion of the cell that can then signal the next neuron

Question 11

where is the AP generated in a neuron

Answer 11

axon hillock

Question 12

difference b/w anterograde and retrograde movement in a neuron

Answer 12

anterograde - AP goes from cell body to axon terminal

retrograde - AP goes form axon terminal to cell body

Question 13

what are the 3 types of neurons based upon structure

Answer 13

Multipolar(most) , bipolar (rare) , unipolar

Question 14

what are the 3 types of neurons based on function

Answer 14

afferent (sensory), efferent (motor), interneurons

Question 15

multipolar neurons carry out what neuron function

Answer 15

motor(efferent) or internuerons

Question 16

bipolar neurons carry out what function

Answer 16

special sensory neurons

Question 17

unipolar neurons carry out what function

Answer 17

general sensory neurons

Question 18

what are the 2 most common types of synapses

Answer 18

axodentritic (axon terminal and dendrite)

axosomatic (axon terminal and cell body)

Question 19

what is the difference b/w presynaptic and postsynaptic neurons

Answer 19

pre is signal carrier before synapse

post is carrying signal after synapse

Question 20

what is the difference b/w electrical and chemical synapses

Answer 20

electrical - neurons can touch and exchange AP via gap junctions, rapid communication
chemical - slower cuz must transfer AP to a chemical signal to diffuse across synaptic cleft, then back to electrical AP

Question 21

explain the process of transferring information across a chemical synapse

Answer 21

1- impulse arrives at synaptic cleft
2- depolarization opens voltage gated Ca channels
3 - Ca signals release of neurotransmitter
4- neurotransmitter diffuses across synaptic cleft
5-neurotransmitter binds and opens ligand gate channel
6 - ions flow across postsynaptic membrane = AP

Question 22

what are the 3 ways a neurotransmitter can be removed from a postsynaptic receptor in a chemical synapse

Answer 22

1 - enzymatic degradation
2 - recycled by presynaptic terminal for later use
3 - diffusion out

Question 23

what are the 4 neuroglia cells found in the CNS

Answer 23

astrocyte, microglial, ependymal, oligodendrocyte

Question 24

what are the 2 neuroglia cells found in the PNS

Answer 24

schwann cells, satellite cells

Question 25

what neuroglia cells in the CNS are predominant in the white matter

Answer 25

oligodendrocytes

Question 26

what neuroglial cell in CNS is predominant in the gray matter ?

Answer 26

astrocytes (largest of all glial cells)

Question 27

what is the difference b/w oligodendrocytes and schwann cells

Answer 27

oligodendrocytes - in CNS, wrap many axons | schwann cells - in PNS, wrap 1 axon

Question 28

what neuroglia cells would be found lining ventricular spaces of the brain, and what are their function

Answer 28

ependymal cells - regulate blood-CSF barrier of choroid plexus

Question 29

which glial cell can be recognized by its elongated nucleus, what is the cells role ?

Answer 29

microgli cells - immune defense for CNS (originate from monocytes)

Question 30

what makes the white matter in the CNS white ?

Answer 30

myelin sheath made form oligodendrocytes

Question 31

what makes the gray matter in the CNS actually gray

Answer 31

lack of myelin and numerous Nissl bodies

Question 32

what is a cluster of nerve cell bodies in the CNS called

Answer 32

nucleus

Question 33

what is a cluster of nerve cell bodies found in the PNS called

Answer 33

ganglion

Question 34

what is a bundle of neuronal axons in the CNS called

Answer 34

tract

Question 35

what is a bundle of neuronal cell bodies found in the PNS called

Answer 35

nerve

Question 36

what are the 3 connective tissue coverings around nerve from largest to smallest

Answer 36

epineurium, perineurium, endoneurium

Question 37

how many pairs of cranial nerves are there and where do the originate from

Answer 37

12 pairs at the brain

Question 38

how many pairs of spinal nerves are there and where do they originate from

Answer 38

31 and originate at the spinal cord

Question 39

what is the function of a myelin sheath

Answer 39

``` protect and insulate axons from others increase speed (more myelin=faster impulse conduction) ```

Question 40

what is the neurilemma in PNS

Answer 40

area outside of myelin sheath in a nerve fibers that contains the organellses and nucleus of schwann cells

Question 41

the rate of impulse propagation down an axon depends on what two things

Answer 41

axon diameter, presence of myelin

Question 42

what is the difference b/w continuous vs. salutatory conduction

Answer 42

continuous is for unmyelinated axons | salutatory is for myelinated axons and regenerates AP at every node of ranvier