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Histology > Nervous Tissue > Flashcards

Flashcards in Nervous Tissue Deck (81):
1

Describe the basics of the neural tissue (cells, ECM, & vascularization)

- abundance of cells
- scarcity of ECM
- Well-vascularized

2

Neurons are supported by a small amount of what CT?

mainly collagen

3

Neurons are also closely associated by what supporting cells?

Schwann cells, satellite cells, gila

4

Clusters of the cell bodies of neurons in the CNS

Nuclei

5

Clusters of the cell bodies of neurons in the PNS

Ganglia

6

Bundles of neuronal processes in the CNS

Tract

7

Bundles of neuronal processes in the PNS

Nerves

8

Areas of the CNS containing predominantly myelinated neuronal processes

Whit matter of the CNS

9

Areas of the CNS containing predominantly neuronal cell bodies (they may be aggregated to form nuclei; they may form layers; or, as in the spinal cord, a mass of tissue which shows a butterfly-shaped image in cross sections of the spinal cord.)

Gray matter of the CNS

10

the neuron is composed of a cell body, referred to as the ..., and one or more cell processes.

soma or perikaryon

11

Cell processes are classified on the basis of function, Those which function in the reception of stimuli are termed ...

dendrites

12

If the neuronal soma functions as a receptor site it is included in the ...

dendritic zone

13

The single process that conducts an impulse away from the dendritic zone is termed the ...

axon

14

What is the effector portion of the neuron?

Nerve terminals

15

Unipolar neurons have a single process. They are common in ...

sensory ganglia; sensory modality

16

Bipolar neurons have two processes. They are associated with ...

special senses of sight, and smell

17

Multipolar neurons have three or more processes. They are common in the CNS, ..., also in the PNS in the ...

CNS motorneurons
PNS in the sympathetic ganglion

18

The supportive cell of the CNS

Neurogila

19

The supportive cell of the PNS

Neurilemma (Schwann cells)

20

The supportive cell of the ganglia

Satellite cells

21

What is the most abundant type of gila cell?

Astrocytes

22

Neurogila cell that anchor neurons to their blood supply

Astrocytes

23

What 2 things do Astrocytes do to regulate the external chemical environment of neurons?

- remove excess ions, notably Potassium
- Recycle NTs released during synaptic transmission

24

What neurogila cell coats axons of the CNS with their cell membrane, called myelin, producing the myelin sheath?

oligodendrocytes

25

These neurogila cells line the cavities of the CNS and make up the walls of the ventricles

Ependymal cells

26

What are the 2 functions of the ependymal cells?

Secrete CSF & beat their cilia to help circulate that CSF

27

These supportive cells of the CNS are not technically neurogila, but they are specialized .... capable of ... that protect neurons of the CNS.

macrophages capable of phagocytosis

28

CT proper forms what three things?

- meninges of the CNS
- capsules of ganglia
- fibrous storm of the PNS

29

Where are neuronal cells bodies found?

- nuclei & gray matter of the CNS
- within the ganglia in the PNS

30

What is the euchromatin content of the nucleus of a neuron?

there is abundant euchromatin
- nucleoplasm is typically pale

31

What appears as basophilic granules or clumps of material in cells prepared for LM?

Nissl substance

32

Nissl substance represents concentrations of ..., which may extend into the ...

rER
- may extend into the dendrites but not the axon

33

Abundance of Nissl Substance suggests ...

active synthesis of proteins

34

Neurofibrils are made up of ..., like those seen in other cells

intermediate filaments and microtubules

35

Intermediate filaments and microtubules of neurofibrils may function in the transport of materials ...

out of the SOMAL region and distally in CELLULAR PROCESSES

36

What accumulates in the soma as a neuron ages?

lipofuscin pigment (yellow-brown)

37

Lipofuscin pigment can be seen confined within vesicles , which may have been lysosomes at an earlier time. The pigment represents an ...

indigestible end-product by lysosomal activity

38

What is the only organelle not present in dendrites?

Golgi

39

The site of axon origin from the cells body is made conspicuous by the abrupt disappearance of ...

Nissl substance

40

the origin of the axon, is called the ..., and is seen as an area of pale cytoplasm

axon hillock

41

The axon gives off occasional branches, along its course, called....

collaterals

42

The axoplasm has no ...

GA, rER, or ribosomes

43

The axoplasm has no mechanism for ...., therefore is is dependent on flow of materials from the cell body.

protein synthesis

44

Bidirectional transport of molecules and selected organelles along the axon.

axoplasmic transport

45

Moves materials from the soma to axon and dendrite terminals.

Anterograde transport

46

What er the microtubule associated proteins for anterograde transport?

Kinesin & ATP

47

Transport relies on the microtubule-associated protein ... to move materials from the periphery of axons and dendrites to the soma.

Dynein

48

Which axoplasmic transport system only employs the fast method of conveyance?

Retrograde

49

In both forms of axoplasmic transport, ... establish a system of "rails" extending the length of the axon or dendrite.

microtubules

50

what % of the myelin is represented by lipid?

80%

51

What % of the myelin is represented by protein?

20%

52

The amount of myelin surrounding an axon is directly proportional to the axon's ...

diameter

53

Myelination in the CNS is accomplished by ....

oligodendrocytes, a type of glial cell

54

During conduction of an excitatory impulse, generation of the AP occurs sequentially at each node (the impulse "skips" from node to node). This is called ...

Saltatory conduction

55

Encircling the myelin when it is present, is the Schwann cell. The embrace of the Schwann cell constitutes the ...

Neurilemma

56

The neurilemma can't be seen at the LM level but its presence may be indicated by a ...

nucleus

57

Synapse located between axon & dendrite

axodendritic

58

Synapse located between axon & cell body

axosomatic

59

Synapse where one axon contacts another axon near its beginning or end. (comparatively infrequent)

axoaxonic

60

Connections between the ANS and .... are unusual in that no special junctions (synaptic clefts) are formed. Instead bulbous enlargements of the axon, with aggregates of synaptic vesicles, are seen adjacent to the muscles cells

Heart muscle & Smooth muscle

61

The peripheral nerves are composed of ... & ...

nerve fibers (axons & their ensheathments) & CT

62

Nerve fibers (axons) occur in bundles, or ...

fascicles

63

Fascicles are gathered together by a surrounding layer of ... to form a nerve

dense CT

64

The sleeve of dense CT enclosing the entire nerve is termed the ..., and extensions of this may penetrate between the enclosed fascicles.

Epineurium

65

Immediately surrounding each fascicle is a thin layer of concentrically arranged dense CT, the ...

perineurium

66

Within the fascicle and around each nerve fiber is a meshwork of fine collagen fibers with occasional fibroblasts. The fibrous framework is called the ...

Endoneurium

67

Blood vessels and lymphatics course in the ... and supply capillaries within the ....

epineurium; endoneurial tissue

68

A collection of nerve cell bodies in the PNS

Ganglion

69

Each cell body is enclosed by a single layer of ...

flattened satellite cells

70

Satellite cells are homologous to and continuous with

Schwann cells which invest axons

71

Immediately superficial to the satellite cell layer are ...

fine collage fibers & fibroblasts

72

Fine collagen fibers & fibroblasts are continuous distally with ...

the endoneurium of associated nerve fibers

73

The ganglion is encapsulated by ..., which is continuous distally with the ... of the associated nerve

moderately dense CT; Epineurium

74

Where is the sensory or dorsal root ganglia found?

roots of spinal & cranial nerves

75

where are the nuclei of sensory ganglia located?

centrally

76

What type of neurons are sensory ganglia composed of?

unipolar

77

Sensory ganglia have abundant ... cells

satellite cells

78

Where are parasympathetic ganglia found?

in the walls of organs

79

Autonomic ganglia nuclei are ...

eccentric nuclei

80

What type of neurons are autonomic ganglia?

multipolar neurons

81

What is in the soma of autonomic ganglia?

Lipofuscin pigment