Nervous Tissue Flashcards
what is nervous tissue
-relays signals
-formed by neurons
-divided into CNS and PNS
what is the CNS made up of
-brain and spinal cord (neurons)
what is the PNS made up of
-nerves and ganglia
-outside of the brain - nerves
what are neurons
-functional unit of the nervous system
-receive, process , store, transmit info to and from other neurons, muscle cells or glands in the body
-dendrites receive the signal
-axon sends signal
neuroglia
support cells
-do not conduct impluses
-support myelin sheath
like astro,oligeio
they are self generating and susceptible to mutation
astrocyte
-largest
-in CNS
connect neuron and capillaries
-feeds the brain - transfers nutrients from blood to the brain
-form blood brain barrier
-keep brain healthy
microglia
-CNS
-phagocytic function
-
ependymal cells
cns
-line fluid filled cavities of the brain and spinal cord
-resemble epithelial cells
-they have cilia to move the CSF
oligodendrocytes
-CNS
-membrane tipped arms
-hold axons together
-produce myelin sheath
-move info faster
look like criss crosses
Schwann cells
-pns
satellite cells - schwann cells that surround the cell body of the neuron
-form SPIRALS (not arms like oligo) around the axons
-myelin sheath around axon
-like oligio but in PNS
-look like straight line
what is the myelin sheath
- lipid rich layer around the axon fibers
-insulation and increases speed of conduction
–not continuous like the nodes of Ranvier
what are non myelinated axons
-small diametric axons in the cytoplasm of the neuroglial cells
-not wrapped around axons
-slow conductions
white matter and gray matter in brain vs the spinal cord
-it is reversed
in the brain the grey matter is on the outside and white inside
-in the spinal cord white on the outside and grey on the inside
GM - Cortex of the brain – controlled by neurons
WM Tract – allows communication to and from grey matter
what is the cerebrum
-largest part of the brain
- sensory motor
-grey outer STAINS LIGHTER
-the outer layer has:
neurons - large cells dendrites and axons (on the slide itll look like a little tail is coming from it -dendrites)
-neuroglial cells All 4 types – no Schwann cells
-unmyelinated axons ONLY
white matter STAINS DARKER
-inner layer
- all neuroglial cells and non and myelinated cells
All 4 types of neuroglial cells are present in both WM and GM – no Schwann cells
what is the cerebellum
2nds largest
under the lobe
movement and coordination
outer- grey - neurons, glial cells non mye ONLY, (looks more dense)
3 components in the grey matter :
1Granular layer - neuroglial cells.
2. Molecular layer – neuroglial cells.
3. Purkinje cells - specialized neurons. in-between granular and molecular layer
inner white STAINS DARKER- contains NO NEURONS does contain neuroglial, mye and non mye
looks like a cauliflower
All 4 types of neuroglial cells are present in both WM and GM – no Schwann cells
the spinal cord has
is in the spinal cavity
-carries signals from brain to spinal cord
-white matter -outer
-grey matter - inner (dorsal/post horn and ventral/ante horn)
central canal -the middle of the cord in H shape is lined by ependymal cells
Dorsal and ventral fissures are the indentations (divided into halves)
All 4 types of neuroglial cells are present in both WM and GM – no Schwann cells
sPINAL CORD – GREY MATTER
Inner layer; H-shaped.
* Composed of:
* Anterior horn cells (AHC).
* Large neurons.
* Motor neurons - voluntary skeletal muscle control.
* Located in anterior horn.
* Neuroglial cells.
* Non-myelinated axons
white matter in spinal cord
- surround the H shape
-contains NO NEURONS neuroglial cells, mye and non mye
-large bundles of axons are called tracts
Special stain – Luxol fast blue.
* Stains myelin sheaths dark blue
what does the PNS consists of
-nervous tissue outside the brain
-have relay nerve stations called ganglia
-12 pairs of carnial nerves
made of bundles of axons, mixed, sensory + motor cranial nerves , comes from the brain
-31 pairs of spinal cord nerves all mixed
DORSAL ROOT GANGLION - IS THE SWELLING IN THE DORSAL ROOT
What are ganglia
relay stations of the bodies nervous system - have afferent (sensory) and efferent (motor) fibers
cell body neurons - larger in the PNS
Nervous tissue outside of the CNS is what
Peripheral nerves (HAVE A WAVY CUT)
-afferent and efferent nerve fibers
-composed of fascicles with each fiber having Schwann cell
-somatic or autonomic
types of connective tissue support
endo NEURIUM - CT fibers around EACH individual axon
peri - Connective tissue fibers surrounding a nerve fascicle.
epi -Outermost layer of dense connective tissue fibers surrounding the ENTIRE nervous tissue.
* In the brain, this layer is also known as the meninges
(DENSE IRREGULAR CONNECTIVE TISSUE)
SKELETAL FIBRES LOOK LONG
GLANDULAR EPI
LOOK LIKE CLOUDS OR BUBBLES ALL TOGETHER
