EXAM2_HE14_15_Nervous_Tissue

Question 1

4 stains used for Nervous tissue & ex

Answer 1

1. HE
2. NISSL (base-like-cell bodies)
3. Golgi (silver based- processes & bodies)
4. Myelin- lipid in myelin

Question 2

3 types of neurons and function of each

Answer 2

1. Multipolar (motor efferent)-interneurons
2. Pseudounipolar (Sensory afferent)- post root ganglia & CN sensory ganglia
3. Bipolar (most rare)- single dendrite- Retina, CNI,VIII

Question 3

3. Multipolar neuron features

Answer 3

1. Euchromatic prominent nucleolus
2. Basophilic
3. Nissl Bodies (toluidine blue nissl stain)

Question 4

Nissl bodies

Answer 4

collections of RER & FREE Ribosomes arranged as polyribosomes (polysomes)

Question 5

Cytoplasmic components & functions of neurons

Answer 5

Lots of Nissl bodies and polyribosomes- PROTEIN SECRETION of NTM- lots of intracellular proteins

Question 6

Dendrite structure

Answer 6

larger diameter than axon- not myelinated- Proximal parts have cytoplasmic organelles- Nissl bodies and golgi complexes

Question 7

Axon basic structure

Answer 7

originates from cell body at axon hillock
-no nissl bodies/golgi
-no protein production
-

Question 8

Initial segment

Answer 8

1st part of axon after axon hillock-
no nissl bodies or golgi
Site where AP is generated

Question 9

1. What does presence of mitochondria indicate in axon?
2. Where are protein components of microtubules and neurofilaments synthesized?
3. What is the function of the neurofilaments?

Answer 9

1. Transport
2. Polysomes in cell body
3. tensile strength

Question 10

AXONAL transport- 2 types and direction. What do viruses do?

Answer 10

-Req ATP
-MT’s & motor proteins (kinesin/dynein)
-transport organelles, synaptic vessels
1. Anterograde- away from cell body to MT/Kinesins
2. Retrograde- toward cell body MTs and Dyneins.
virus-use retrograde-toward cell body

Question 11

Collaterals & Terminals

Answer 11

neurons can branch to other axon terminals (boutons)

cardiac muscle doesn’t have boutons

Question 12

Internodal segments- nodes of Ranvier-
What stain used?
What appearance in HE stain?

Answer 12

Silver stain
segments of myelinated axon
gaps between internodal segments are nodes of ranvier
pale/white “moth eaten” w/ HE- high lipid content of myelin

Question 13

Myelin formation

Answer 13

Glial cell + its cytoplasm wrap around neuron pushing nucleus to outside.
-phospholipid structure

Question 14

Non-myelinated axons

Answer 14

Smaller diameter axons
slower conduction velocities (no myelin)
axon enveloped by glial cell+plasma membrane but NO wrapping

Question 15

3 types of synapses

Answer 15

1. axosomatic (axon to cell body)
2. Axodendritic (axon to dendrite or dendritic spine)
3. Axoaxonic (axon to axon)

Question 16

Where is CNS neurons and glia derived from?
PNS neurons and glia?
When do neuropores close?

Answer 16

CNS- Neuroectoderm- neurotube
PNS-Neuroectoderm-neurocrest
Week 4 neuropores close

Question 17

how do you classify neurons if they are CNS or PNS?

Answer 17

by developmental origin

and location of cell obdy

Question 18

CT of CNS- what called? what does it line? 3 types

Answer 18

MENINGES: lines cavities of CNS

1. Dura Mater- DIRCT (toughest)
2. Arachnoid mater- Subarachnoid space
3. Pia Mater- LCT (remains outer surface only- not in grey /white matter)

Question 19

Grey Mater-Structure-Location
White Mater
What’s Unique to both GM and WM?

Answer 19

GM- CNS nuronal cell bodies (Nuclei)
WM- myelinated axons (Tracts)
NO CT IN GM OR WM

Question 20

Nuclei

Tracts

Answer 20

N- collections of related neuronal cell bodies

T- collections of related nerve processes (axons)

Question 21

Neuropil- What is it? What 3 things does it contain? how do you identify it? What could you confuse it with at LM?

Answer 21

The “Feltwork” around nuclei in the grey matter:
1. unmyelinated neuronal cell processes
2. glial cell bodies & processes
3. small blood vessels
Looks like LCT but ther is NO CT in GM or WM

Question 22

Astrocytes- Origin, Locations, 4 functions

Answer 22

CNS Glial Cells- Neural Tube- in GM and WM
many cell processes radiate from cell body
1. guide migrating neurons during CNS development
2. Glia Limitans; Regulate ionic environment in ECM
3. Support blood/brain barrier
4. Proliferate at sites of injury (gliosis)

Question 23

Glia Limitans

Answer 23

Thin barrier of astrocyte FOOT PLATES associated with parenchyma basal lamina surrounding the brain and spinal chord.

SEPARATES PIA & CNS TISSUE

regulates movement of small molecules and cells into brain and supports blood-brain barrier.

Astrocytes can regulate endothelial cells to adjust the leaky ability of the blood vessels

Question 24

Layers of the head

Answer 24

Scalp>Cranium (skull)>Dura>Arachnoid>subarachnoid space> Pia>Glia limitans>cerebral cortex

Question 25

What is the Blood brain barrier formed by? What is the most common and most aggressive malignant primary brain tumor and where is it derived from?

Answer 25

tight junctions between capillary endothelial cells Glioblastoma multiforme- GBM Astrocytoma of glial cells - astrocytes

Question 26

Oligodendrocytes- Origin-location-function- | What is demyelinating disease of oligodendrocytes?

Answer 26

CNS glial cells- Neural tube- found In WM 1. myelination of CNS axons - can myelinate more than one axon - multiple internodal segments per axon - MS of CNS oligodentrocytes

Question 27

Microglia- Origin? Pathway? Location? Function?

Answer 27

CNS Glial cell- found in GM & WM Monocytes>BBB>CNS>divide into microglia Function as resident macrophage and Immune defense of CNS.

Question 28

Ependymal Cells- Origin? Location? Function? What is the main component of Ependymal cells?

Answer 28

CNS glial cell- originate from Neural Tube- Cuboidal- Makes CSF- - Line the central canal of spinal cord & ventricular system of brain 1. A component of choroid plexus- Produce & circulate CSF

Question 29

What are the 4 Glial cells of the CNS? Functions? All three are derived from which place? where is the 4th glial cell derived from?

Answer 29

1. Astrocytes (form glia limitans/support BBB) 2. Oligodendrocytes (myelinate axons) 3. Microglial (phagocytosis macrophages bone marrow) 4. Ependymal (make and circulate CSF)-Choroid plexus NEURAL TUBE DERIVED EXCEPT MICROGLIA (macrophages in bone marrow)

Question 30

Where is CT in the grey/white matter of CNS? Why only 3 places? Is there a external lamina?

Answer 30

``` CT COVERINGS (outer surfaces) 1. Dura 2. Arachnoid 3. Pia Glia limitans present so no CT or external lamina with grey or white matter. ```

Question 31

What are Tracts? where located?

Answer 31

Tracts are myelinated axons of glia in the White Matter

Question 32

What are Nuclei? where located?

Answer 32

Nuclei are neuron cell bodies in the Grey Matter

Question 33

Origin of brain/spinal cord/ neurons & glia ?

Answer 33

Neural tube

Question 34

Origin of Neurons & nerve processes & glia outside brain and spinal cord?

Answer 34

Neural Crest

Question 35

Collections of functionally-related neuronal cell bodies

Answer 35

Ganglion

Question 36

Collections of functionally-related nerve fibers

Answer 36

Peripheral nerves

Question 37

What does silver stain highlight? What about Myelin stain?

Answer 37

highlights the cell bodies and processes. the grey matter. | highlights the lipids of myelin shows reverse of silver stain. highlights the white matter

Question 38

What make up the Grey matter in the CNS? Functionally related nerve processes? what do they make up?

Answer 38

Nuclei (cell bodies of neurons) | Tracts (axons of the nuclei) - make up the white matter

Question 39

What is the dead give away that you are looking at a neuron in grey matter?

Answer 39

Nissl bodies (usually around a bullseye)- its the neuron cell bodies (nissl)

Question 40

What occurs in brain damage repair? What happens if repair goes too far? What repairs better CNS or PNS? Why?

Answer 40

Gliosis at brain injury - astrocytes proliferate creating a bridge and gap over that area - Too much astrocyte proliferation creates a GLIAL SCAR & prevents regeneration of axons - cns doesn't regenerate as well as pns

Question 41

GBM

Answer 41

neoplastic changes to astrocytes that create malignant tumors

Question 42

External lamina functions? needed in CNS?

Answer 42

adherence, filtration barrier; | not needed b/c we have astrocytes that do this

Question 43

Round cells with euchromatic nuclei, prominent nucleolous, Lots of cytoplasm with tiny cells forming complete ring around the cells. What does a LMN look like in conjunction?

Answer 43

chocolate Malt balls pseudounipolar neurons -satellite cells around cell body- glial- Neural Crest Lower Motor Neuron of CNS (has nissl bodies w/ bullseye in middle)

Question 44

Pseudounipolar cells what are the two parts?

Answer 44

- Central process (into cns) and | - Peripheral process (to muscles)

Question 45

Posterior Root Ganglion

Answer 45

No synapses. Has a pseudounipolar neuron for sensory and a Lower Motor Neuron for action

Question 46

Nerve fibers less bundled- Neuronal cell bodies less densely packed- more scattered. Tiny cells form incomplete ring around the cells . Euchromatic nuclei, nucleolus. Why cells so spread apart?

Answer 46

Motor ganglia- autonomic: sympathetic & parasympathetic | Synapses occur here!

Question 47

4 types of peripheral nerves

Answer 47

Axons- 1. Cranial nerves & branches 2. Spinal roots, nerves, rami & branches 3. Sympathetic & Parasympathetic nerves 4. Visceral sensory nerves

Question 48

Epineurium- Structure? What does it surround? Function?

Answer 48

DiRCT/TypeI collagen/ ELASTIC FIBERS - Surrounds entire peripheral nerve - interacts w/ adjacent neurovasuclar structures

Question 49

Perineurium- Structure? What does it surround? Function?

Answer 49

DiRCT but less dense/still Elastic | -Surrounds bundles of axons called Fascicle

Question 50

Endoneurium- Structure? what does it surround? | What makes ECM? Is CT found in CNS?

Answer 50

LCT & Reticular TypeIII collagen -surrounds individual myelinated & unmyelinated axons -ECM made by fibroblasts & schwann cells (glial cells) NO CT IN CNS!

Question 51

Thick black border around cells what is it? what surrounds these cells?

Answer 51

myelin around cells- endoneurium

Question 52

SCHWANN CELL- origin? Functions? disease? What advantage over oligodendrocyte in CNS?

Answer 52

SECRETORY! from Neural crest (PNS) 1. Reticular fibers (type III collagen into endoneurium) 2. External lamina (TypeIV, PGs')(separates schwann cell from endoneurium)-blood nerve barrier - external lamina guides repair - one schwann cell wraps only one internodal segment on one axon NO EXTERNAL LAMINA IN CNS-

Question 53

What did you forget about schwann cells?

Answer 53

They envelop unmyelinated axons- think about what this will look like at TEM

Question 54

Sensory Ganglia- What type of neurons? what part of functional nervous system?

Answer 54

Sensory ganglia- Posterior root ganglia- Pseudounipolar neurons- Somatic reflex NO SYNAPSES occur within the ganglia

Question 55

Motor ganglia- what type of neurons?

Answer 55

Autonomic- multipolar neurons- visceral reflex | Has synapses