Lecture 1 CNS Histology Flashcards Preview

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Flashcards in Lecture 1 CNS Histology Deck (38):
1

How long is the lucid interval for epidural hematoma?

How long is the lucid interval for epidural hematoma?

2

What compose the coverings of the CNS?

From exterior to interior
1. Skull
2. Dura mater
-two layers of dense collagenous connective tissue with large venous sinuses

SUBDURAL (POTENTIAL) SPACE

3. Arachnoid mater
-thin membrane containing a mixture of FIBROBLASTS and ARACHNOIDAL cells (meningothelial cells)
-adheres directly to dura

SUBARACHNOID (ACTUAL) SPACE
-CSF is found here

4. Pia mater
-layer of cells tightly affixed to brain
-anchors arachnoid trabeculae
5. Brain parenchyma

3

What does parenchyma mean?

The essential or functional elements of an organ

4

What are the Virchow-Robin spaces?

Essentially subarachnoid spaces (spaces in between the arachnoid and pia mater) that surround vessels within the brain
Pia mater adheres tightly to brain parenchyma
-brings arachnoid trabeculae, thus subarachnoid space, with it

5

What are arachnoid trabeculae?

Delicate strands of connective tissue that connect the arachnoid and pia mater

6

Where are sinuses located?

In the dura

7

What is the function arachnoid villi (aka arachnoid granulations)?

They allow CSF to diffuse into the sinuses for drainage

8

How do you identify arachnoid cells histologically?

Concentrated at tips of arachnoid villi
Oval nuclei
Can form prominent whorls or psammoma bodies

9

What is a psammoma body?

A round collection of calcium

10

What is the basis of meningioma?

Proliferation of arachnoid cells

11

What happens to the arachnoid as we age/are subjected to infection?

Clear arachnoid becomes OPACIFIED
-collagen deposition

12

What are the leptomeninges?

Means thin meninges
Refers to the pia and arachnoid mater

13

What are the main cellular elements of CNS histology?

1. neurons
2. glial cells
-astrocytes
-oligodendrocytes
-ependymal cells
3. Microglia
4. Choroid plexus cells
5. blood vessels/blood cells (RBC/WBC)
6. Meningothelial (arachnoid) cells
7. Bone/cartilage
8. Pituitary cells

14

What is a key histological feature of the cell body of neurons?

A prominent nucleolus
-surrounded by a large nucleus

15

What are Nissl bodies/Nissl substance?

-sites of protein synthesis, eg RER
Proteins can be visualized by cresyl violet aka Nissl stain

16

What is the delineating microscopic feature of the axon hillock?

The ABSENCE of Nissl substance

17

What are Neuropils?

Background of the CNS histology slide
Functional definition: pink shit that is in between the astrocytes, neurons and oligodendrocytes
“A feltwork of interwoven dendrites and axons and of neuroglial cells in gray matter of CNS”

18

What are delineating histologic features of astrocytes?

In cross section, small with a lot of nuclei
-in both white and grey matter
Are stained for GLIAL FIBRILLARY ACIDIC
PROTEIN (GFAP)

19

What is glial fibrillary acidic protein (GFAP)?

It is the intermediate filament in astrocytes that are stained
To ID astrocytes

20

What are delineating features of oligodendrocytes?

Egg shaped (nucleus with white shit surrounding it)
-in both white and grey matter
-one oligodendrocyte myelinates up to 50 axons (so a lot of Nissl substance

21

What are Ependymal Cells?

Lines the ventricles of the brain and the
central canal of spinal cord
Serve to absorb, secrete and propel CSF
-Links the ventricular, vascular and
The intraparenchymal compartments of CSF

22

What is the delineating histological feature
Of ependymal cells?

Cuboidal cells with microvilli ontop
-linked by tight junctions

23

What is the choroid plexus? Histological features?

Projectiosn of vascular stroma derived from meninges
Secretes CSF in ventricles
Cuboidal epithelium

24

How are neurons organized in the CNS

1. Cortex
-neocortex
-Archicortex or Palleocortex (any cortical structure that has LESS than 6 layers)
2. basal ganglia (deep gray nuclei)
3. cerebellar cortex/nuclei
4. brainstem nuclei
5. spinal cord

25

What are the six layers of the neocortex?

1. Molecular
2. External Granular
3. External Pyramidal
-axons point toward the pia
4. Internal Granular
5. Internal Pyramidal
6. Plexiform

26

What are the areas of the cortex that have large pyramidal layers? Large granular layers?

M1 has large pyramidal layers
V1 has large granular layers

27

What are the cell layers of the cerebellar cortex?

1. Molecular layer
2. Purkinje cell layer
3. Granular Cell layer

28

What does CA stand for in terms of hippocampus?

Cornu Ammonis (or Ammonis horn)

29

What region of hippocampus is most sensitive to Injury?

CA1 (aka Sommer sector
-sensitive to ischemia, seizure, Alzheimers

30

What are the characteristics of damage to neurons?

1. acute ischemic injury (RED NEURONS)
2. chronic injury (cell loss)
3. neuronal inclusions like LIPOFUSCHIN
4. Reactive gliosis
5. Microglia and inflammatory infiltrates

31

What is the delineating feature of CNS that has gone acute ischemic injury?

Red Neurons
-intense cytoplasmic eosinophilia
-loss of Nissl substance
-nucleus is darkly stained w/o nucleolus
-shrunken cell body

32

What is the delineating factor of neuron aging?

Lipofuschin
Brown shit
-comes from oxidized fatty acids

33

What are the three pigmented nuclei of the brain?

1. Substantia nigra
2. DMX
3. locus ceruleus
(catecholaminergic…dopamine for instance…neurons)
Pigmented = neuromelanin
Not to be confused with lipofuschin

34

What does a Lewy body look like?

A CYTOPLASMIC round INCLUSION

35

What is Glial Fibrillary Acidic Protein and what is its significance?

GFAP acts as a diagnostic marker for disease
-increased GFAP is indicator of hypertrophy and hyperplasia of astrocytes
-analagous to fibroblasts in injury

36

What is gliosis?

The inflammation of glial cells
More specifically, the hypertrophy/hyperplasia of astrocytes

37

What is the main effector of reaction to injury in the CNS?

Astrocytes
Via hypertrophy and hyperplasia cause gliosis

38

What happens to microglia in the event of injury?

Hyperplasia
Elongated nuclei
Increased elongated cytoplasmic processes