Histo-Cns

Front 1

cells of the cns (2)

Back 1

neurons
neuroglia

Front 2

Neurons - specialized for:

Back 2

a. excitation (or inhibition)
b. impulse conduction

Front 3

2. Neuroglia (Glia) - interstitial cells

Back 3

a. Astrocytes
b. Oligodendrocytes
c. Microglia (mesoglia)
d. Ependymal cells

Front 4

grey matter

Back 4

unmyelenated cell processes plus glial cells

Front 5

IN CNS a cluster of nn cell bodies w/ similar fx

Back 5

nucleus

Front 6

OUTSIDE CNS a cluster of nn cell bodies w/ similar fx

Back 6

ganglia

Front 7

location of grey matter

Back 7

a. central part of spinal cord
b. brain stem (portions)
c. cortical tissue (of brain)

Front 8

White Matter

Back 8

Long processes of neurons (predominantly myelinated) plus glial cells.

Front 9

Functionally related processes are grouped in ______

Back 9

tracts

Front 10

Mixed Areas

Back 10

Neuron cell bodies plus myelinated cell processes plus glial cells. Includes
portions of brain stem (medulla, pons, midbrain.)

Front 11

what is the connective tissue in CNS?

Back 11

** No C.T. fibers except some associated with capillaries.

Front 12

T/F there is abundant capilaries in CNS

Back 12

T

Front 13

size of neuronal cell body (perikaryon)

Back 13

4µm to 135 µm

Front 14

describe nucleus of neuronal cell body (perikaryon)

Back 14

- usually central except for the neurons of the autonomic nervous system (have eccentrically placed nuclei).
- lots of euchromatin.
- single, large nucleolus near the center of the nucleus.

Front 15

What does the following describe:

-identified at the light microscopic level as blue patches (With H &
E stain).
- stacks of flattened cisternae of rough E.R. mixed with lots of free
ribosomes.
- chromatolysis: following nerve injury, there is a dissolution of Nissl
substance.
- located in the perikaryon and dendrites (NOT in axons).

Back 15

Nissl substance

Front 16

Cell body (Perikaryon) contains

Back 16

Golgi, mitochondria, microfilaments, microtubules.

Front 17

pigments of Cell body (Perikaryon)

Back 17

- lipofuscin (increases with age of cell).
- melanin: abundant in the substantia nigra of the midbrain.

Front 18

axon hillock

Back 18

proximal part of axon; a little thicker in diameter.

Front 19

axolemma

Back 19

plasmamembrane of axon

Front 20

axoplasm

Back 20

cytoplasm of axon. Lacks Golgi and rER. Free ribosomes
are rare.

Front 21

Axon. Describe size & branches

Back 21

size varies from a fraction of a mm to several feet.

many have collateral branches which leave at right angles
- some have recurrent collaterals that curve back along originating
axon

Front 22

describe dendrites

Back 22

a. much shorter than axons
b. branch dichotomously at right angles
c. contain ribosomes, Nissl, filaments, mitochondria, etc.
d. dendritic transport occurs but little is known of details

Front 23

Multipolar neurons

Back 23

i. many dendritic processes + 1 axon
ii. includes most neurons

Front 24

Bipolar neurons

Back 24

i. two processes: 1 dendrite + 1 axon
ii. location: inner ear, retina of eye

Front 25

Unipolar neuron

Back 25

i. 1 axon only
ii. location: retina of eye

Front 26

Pseudounipolar neuron

Back 26

i. modified unipolar: axonal process + dendritic process
ii. somatic sensory fibers

Front 27

LARGE Neuron is also called?
How large?

Back 27

Golgi Type I

perikaryon to 135µm diameter
axons to several feet

Front 28

examples of Golgi type I

Back 28

Pyramidal cells (cerebral cortex)
Purkinje cells (cerebellar cortex)
lower motor neurons

Front 29

SMALL Neurons also called?
How small?
More prevelent than Golgi type I?
Includes?

Back 29

Golgi type II
1) perikaryon as small as 5µm
2) axons - a fraction of a mm. (usually unmyelinated)
3) vastly outnumber the Golgi type I cells
4) includes interneurons (internuncials)

Front 30

Examples of Golgi type II

Back 30

i. Stellate cell (cerebral cortex)
ii. Cell of Martinotti
iii. Granule cell
iv. Horizontal cell

Front 31

Neuroglia includes:

Back 31

A. Oligodendrocytes
B. Astrocytes
C. Ependymal Cells
D. Microglia

Front 32

What is this describing:

1. Nucleus is spherical with medium to dense chromatin.
2. Numerous cytoplasmic processes project from the cells to wrap around
axons.
* The continued wrapping of the cytoplasmic processes forms a myelin sheath in much the same manner as Schwann cells myelinate peripheral nerves.
* Each process projects to a different axon.
* Thus a single cell wraps portions of several axons and
a single axon is wrapped by several cells.
3. In white matter, these cells are disposed in rows between the
axons while in gray matter they appear to be randomly located.

Back 32

Oligodendrocytes

Front 33

What is this describing:

1. nuclei are larger than other glial cells. Also, somewhat irregular in
shape.
2. contain many processes that project in several directions.
Page 5
3. the ends of the processes widen and spread over the surfaces of
neurons and capillaries

Back 33

Astrocytes

Front 34

Astrocyte Feet

Back 34

-widen and spread over the surfaces of
neurons and capillaries
-Most capillaries are
completely ensheathed by the astrocytic feet.

Front 35

Function of Astrocytes

Back 35

a. support
b. chemical transport (between capillaries and neurons).

Front 36

Types of Astrocytes

Back 36

a. fibrous - present in white matter
b. protoplasmic - present in gray matter

Front 37

What is this describing:

Location: Line the ventricles of the brain and the central canal of the
spinal cord.

2. Structure:
a. cuboidal to columnar in shape
b. ciliated in the ventricles and non-ciliated elsewhere

Back 37

Ependymal Cells

Front 38

What is this describing:

1. small cells with dark, flattened nuclei.
2. origin & function are controversial

Back 38

Microglia

Front 39

One School of thought believes there are two types of Microglia. Most microglia in CNS are neuroectodermal in origin, have no
known function, are called __________.

Back 39

resting microglia.

Front 40

One School of thought believes there are two types of Microglia. In damaged or
infected areas of the brain, a population of microglia known as __________
are identified that are derived from blood
monocytes and are therefore mesodermal in origin and
phagocytic in function.

Back 40

reactive microglia

Front 41

Other school of thought believes all microglia have _______ function

Back 41

phagocytic

Front 42

Neuropil at light microscopic level -

Back 42

neuropil appears as a fine mottled area between
cell bodies of neurons.

Front 43

Neuropil at electron microscopic level

Back 43

1. conglomerate of cell bodies & cell processes of astrocytes along
w/processes of neurons (mostly unmyelinated).
2. fine intercellular spaces between cells and their processes.
3. glycosaminoglycans (hyaluronic acid, chondroitin and heparin sulfates)
present in spaces. Similar to ground substance of C.T.