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Flashcards in Nervous Deck (67):
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Nervous tissue develops from?

Neural tube and neural crest cells

1

2 types of cells in neurons?

Neurons - excitable cells - transmit electrical signals

Neuroglia - nonexcitable cells - support, surround, wrap around neurons

2

Neuron stem cells located?

Lateral ventricles
Hippocampus
Olfactory region

3

Neuron theory and if die?

Independent chain - not influence by other chains

If die, not replaced - post mitotic - highly differentiated

4

Length of axon. Longest axon. Cell body size?

1mm-1m. 1m = sciatic nerve
Cell body - 4-135um

5

Peripheral nervous system (3)
Central nervous system (2)

Hollow organs, nerves, ganglia
Brain (grey matter), spinal chord(csf)

6

3 types of neurons?

Unipolar
Pseudounipolar
Bipolar

7

Neuron Axon length classification? (3)

Golgi 1 - long axon - being from grey matter
Golgi 2 (no or shorter axon) - not send out branches to grey matter

Developed animals - greater amount of golgi 1

8

Functional classification of neurons (3)

Sensory, motor, interneurons (99%)

9

Motor neurons can be ?

Inhibitory or stimulatory

10

Unipolar neuron?

One prolongement
less common in vertebrates

11

Bipolar neuron

1 dendrite
1 axon

12

Pseudounipolar

Sensory gangila, dorsal root gangila

13

Dendrites? Structural(4) detected by (2) max length(1)

Cytoplasmic prolongements.
Branched. Thinner away from body.
Dendritic spines - receive synapses -Detected by florescent staining.
- EM microscope.

Max length 700um

14

Specific stain for neurons? (2) cytoskeleton and nissl bodies?

Cytoskeleton - gold staining
Nissyl bodies - rer polyribosomes - basic staining eg - h and e.

15

Organelles in neurons

Mito, rer, ser, nissl bodies, golgi, nucleus, nucleolus, mt, int filaments (neurofilaments), actin filaments, lipofucins (increase with age)

16

Mito in neurons?
Neurons in terms of mitosis?
What increases with age because of this?

Longi cisternae.
Post mitotic.
Increase of Iipofucins with age

17

What lacks in dendrites and nissl body staining?

Ser

Basic staining - basophillic due to rer and polyribosomes

18

Axon. Function. Length. Diammeter. Sheath. Cytoplasm. Filaments. Organelles

Info to periphery.
Long 1mm to 1m
Uniform diameter, eventually collateral
Simple or complex sheath ( myelin sheath or neurilemma)
Cytoplasm (axoplasm,). Neurofilaments parallel to axis, mt, actin
No organelles involved in protein syn eg rer. Large no of mito

19

Dendrites and axon differences

Dendrites
Ribosomes, rer. Non uniform. No sheath, irregular. Shorter and branches.
Axon
No organelles in protein syn. Uniform diammeter. Long. Not branched. Sheath. Large no of mito

20

Neurofilaments, mt, actin filaments function in neurons?

Neuro Filaments - int filaments - support
Mt - axonal flux regulation
Microfilaments - actin - longi and circ arrangement - rel of net and axonal transport

21

Axonal transport. Motor proteins. And 2 types of transport in terms of speed

Kinesin +, dyenin - map
Fast 50-400mm/day- antero - away - protein, organelles, veesicles
- vesicles pm renewal, organelles to be destroyed
Slow - 1mm / day cytoskeleton, cytoplasmic subunits

22

What type of transport is herpes virus?

Reterograde

23

Glial cells in pns and cn - cell body

Glial cells - CNS
Satellite cells - PNS

24

Glial cells - neuron - axon

Axon - myelin sheath - neurolemma
Schwann cells - PNS
Oligodendrocytes - CNS - connect to multiple neurons

25

Nerve fibre pns

Unmylinated - pale staining - one Schwann cell interacting with more than one axon - actin fil, mt inside axon
Myelinated - Schwann cell wrapped around axon - schmitt-lantermann clefts

26

Layers surrounding axon
Em microscope see ->

Int ext mesaaxon
Em microscope - internodal segment (100-200um)

27

Fibres of cns?

Glial cells - oligodendrocytes - large no of prolongements - wrap around multiple axons

28

Major dense line

Adheion of inner pm
Represents adhesion of inner layer of schwnn cells

29

Intraperiod line

Represent adhesion of outer layer of pm

30

Myeline pathologies

Immune system - auto antibodies - destroyed plp (protolipid protein) mpb(myelin basic protein)
Responsible - myeline degeneration -> multiple sclerosis

31

Myeline sheath function (3)

Insulation, saltatory conduction, nerve regen

32

Schmitt-lanterman clefts

Irregularities in pm due to cytoplasm of schwann cell

33

Myelinated - pns and cns

Pns - white matter + initial tract of nerves
Cns - spinal and cranial nerves

34

Unmylinated areas

Nodes of ranvir
Tactile afferents

35

Presynaptic membrane - ser?

Reprocess endocytotic vesicles -> synaptic vesicles

36

1 neuron connected to max?

10000 synapses

37

Synapses are?

Chemical(diffusion) or electrical(gap junctions)
Unidirectional

38

Synaptic cleft approx size?

25um

39

Different types of synapses?

Axosomatic
Axoaxonic
Axodentritic
Dendrodentritic

40

Proteins in pre-synaptic membrane?

Synapsin 1(connector protein of synaptic vesicles to fodrin filaments)
Fodrin (filamentous protein)

41

Pre-synaptic grid?
Post-synaptic ?

Actin filaments

Electron dense layer

42

How calcium effects vesicle release in presynaptic membrane?

Depolarisation - ca channels open - ca bind to calmodulin - active protein kinase - phosphorylation of synapsin - lose affinity for vesicles and fodrin - vesicles released - v snare on vesicles bind to t snare on presynaptic membrane - endocytosis

43

2 types of synapse

type one - asymmetric - wide cleft - post syn thicker - excitatory

Type 2 - symmetric - equal thickness of post and pre - inhibitory

44

Example of NETs (9)

Ach, serotonin, gaba, dopamine, norepinephine, epinephine, endorphins, glycine, no

45

Ganglion

All body of neurone with satellite cells

46

Glia (5)

Non excitable
49% of cells in nervous
Proliferate - involved in tumours
Synapse stabilisation
Support neurons - mechanical, metabolic support. Delivery of nutrients

47

Pns and cells (2) in cross section and nucleus

Schwann and satellite cells
Nerves and ganglia
Cross section - rounded
Nucleus - nucleuolus

48

Central nervous system (4)

Ependymal cells - line cavities + spaces
Astrocytes - many prolongements - blood brain barrier - protect brain
Oligodendrocytes - myeline sheath -wrap around multiple neurons
Microglia - from monocytes - phagocytosis

49

Schwann cells and nerve regen
And when only possible

Damage to terminal axon
Macrophages/microglia - distal part of damaged nerve - remove cell debris
Schwann cells proliferate - proximal part
Only possible if no damage to cell body

50

Ependymal cells (5)

Apical - cilia
Produce csf
Line ventricles, cavities and spaces
Similar to epithelial cells
May function of stem cells

51

Astrocytes shape and where abudant?

Star shaped and thinly branched

CNS

52

Specific marker for astrocyte is?

GFAP - Int, filament.

Down Regulated during pathology

53

2 types of astrocytes and where found.

Fibrous - white matter - straight, fewer processes
Protoplasmic - grey matter - numerous short branching processes

54

Function of astrocytes (4)

Structural support, repair of scar tissue, phagocytosis, reg. of met blood brain barrier

55

Ananolog of oligodenrocytes in pns?

Schwann cells

56

Oligodendrocytes?

Found in cns. 70% of glial cells
Multiple axon form myeline sheath.
Rounded nucleus, abundant golgi

57

Microglia

Monocyte linage. Phagocytosis
Large no of lysoosmes, lipofucins, vesicles.
Little mt and rer

58

Microglia and pathologies

Involved in inflammatory pathology of brain - contribute to neural pathologies.
Microglia - flattened nuclei - difficult to distinguish.

59

Blood brain barrier? Ans other examples

Formed by astrocytes.
Protoplasmic - grey matter
Fibrous - white matter
Perivascular feet - separate blood vessels from neuron.
Thymus, testis, air.

60

Cross section of blood brain barrier (3)
How different to capp?

Thin endothelial cells - on basal lamina
Epithelial cells connected by - occluding junctions - zo1-2 proteins.
Req specific carrier/transporter - specific mat.
Capp contain pores - no gap junctions

61

Catecholamine net, amino acid net?

Synth from tyrosine - Dopamine, adrenaline, noradrenaline

Aa (mainly cns)- glycine, aspartate, gaba, glutamate

62

Post synaptic sympathetic nervous system net (ans)?

Adrenaline.
Synapse convert nor into adrenaline = adrenergic via enzymes

63

Shwann cell wrapping 4 areas of note?

Intra period line - extracellular space
Major dense line - cytoplasm of shwann cell
Inner and outer mesaxon

64

Thickness of myeline sheath determined by?

Diameter of axon and NOT schwann cell

65

Function of satellite cell and where found.

Form complete layer around cell bodies ganglia
Surrounded by small cuboidal cells - satellite cells.
Maintain microenvironment around cell body,
insulation,
pathway for met exchanges

66

Analog of schwann in pns?

Satellite cells