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Flashcards in Nervous Tissue Histology Deck (42)
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1
Q

what are the 3 functions of the nervous system

A

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

2
Q

what is a collection of axons called in the nervous system

A

nerve

3
Q

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

A
  • neurons/nerve cells

- glia/neuroglia/supporting cells

4
Q

which basic cells of the nervous system are the excitable cells

A

neurons

5
Q

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

A

glia cells (can divide/multiply)

6
Q

what are the 3 special characteritics of neurons

A

longevity
amitotic
high metabolic rate

7
Q

clumps of rough ER and ribosomes found in the cell body

A

Nissl bodies

8
Q

what is a perikaryon and what is its main function

A

neuron cell body, its the biosynthetic control center of nuueron

9
Q

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

A

axon =myelin

dentrite and cell body = unmyelinated

10
Q

what is a axon terminal

A

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

11
Q

where is the AP generated in a neuron

A

axon hillock

12
Q

difference b/w anterograde and retrograde movement in a neuron

A

anterograde - AP goes from cell body to axon terminal

retrograde - AP goes form axon terminal to cell body

13
Q

what are the 3 types of neurons based upon structure

A

Multipolar(most) , bipolar (rare) , unipolar

14
Q

what are the 3 types of neurons based on function

A

afferent (sensory), efferent (motor), interneurons

15
Q

multipolar neurons carry out what neuron function

A

motor(efferent) or internuerons

16
Q

bipolar neurons carry out what function

A

special sensory neurons

17
Q

unipolar neurons carry out what function

A

general sensory neurons

18
Q

what are the 2 most common types of synapses

A

axodentritic (axon terminal and dendrite)

axosomatic (axon terminal and cell body)

19
Q

what is the difference b/w presynaptic and postsynaptic neurons

A

pre is signal carrier before synapse

post is carrying signal after synapse

20
Q

what is the difference b/w electrical and chemical synapses

A

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

21
Q

explain the process of transferring information across a chemical synapse

A

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

22
Q

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

A

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

23
Q

what are the 4 neuroglia cells found in the CNS

A

astrocyte, microglial, ependymal, oligodendrocyte

24
Q

what are the 2 neuroglia cells found in the PNS

A

schwann cells, satellite cells

25
Q

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

A

oligodendrocytes

26
Q

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

A

astrocytes (largest of all glial cells)

27
Q

what is the difference b/w oligodendrocytes and schwann cells

A

oligodendrocytes - in CNS, wrap many axons

schwann cells - in PNS, wrap 1 axon

28
Q

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

A

ependymal cells - regulate blood-CSF barrier of choroid plexus

29
Q

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

A

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

30
Q

what makes the white matter in the CNS white ?

A

myelin sheath made form oligodendrocytes

31
Q

what makes the gray matter in the CNS actually gray

A

lack of myelin and numerous Nissl bodies

32
Q

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

A

nucleus

33
Q

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

A

ganglion

34
Q

what is a bundle of neuronal axons in the CNS called

A

tract

35
Q

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

A

nerve

36
Q

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

A

epineurium, perineurium, endoneurium

37
Q

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

A

12 pairs at the brain

38
Q

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

A

31 and originate at the spinal cord

39
Q

what is the function of a myelin sheath

A
protect and insulate axons from others
increase speed (more myelin=faster impulse conduction)
40
Q

what is the neurilemma in PNS

A

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

41
Q

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

A

axon diameter, presence of myelin

42
Q

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

A

continuous is for unmyelinated axons

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