Exam1Lec4NerveTissue Flashcards
What does the CNS include?
include brain, spinal cord and neural portions of the eye
What does the PNS consists
Peripheral nerves, nerve endings and peripheral nerve ganglia
everything else
The CNS and PNS have what two basic cell types?
Neurons and glia/supporting cells
What are the neuroglia in PNS
Schwann
Satellite
What is the neuroglia in CNS
- astrocytes
- Oligodentrocytes
- Microglia
- Ependymal cells
What neuroglia is used for nourish and protect neurons?
Astrocytes
What cell is used for myelination?
oligodenrocytes-CNS
schwann-PNS
What cell is used for myelination?
oligodenrocytes-CNS
schwann-PNS
What cell is used for myelination?
oligodenrocytes-CNS
schwann-PNS
What cell is immune cells (macrophages)
mircoglia
What cell is epithelial-like cell?
ependymal cells
Where are nissel bodies?
part of soma
order of signaling
dendrite->soma-> axon
What are nissel bodies look like and what are they stained with?
- Ribosomes, rough ER
- They stain blue with hematoxylin (basophilic)
What is lipofuscin pigment?
age pigment: lysosomes with degradation products (residual body)
label
1: Nucleolus
2. Nucleus
3. Nissel bodies
Explain what the differenet types of neurons look like and where they are found
how are neurons classified?
shape (# of things coming off soma)
For multipolar neurons, what are they called in cerebral cortex and cerebellar cortex?
Cerebral cortex: pyramidal cells
Cerebellar cortex: purkinje cells
What type of cells do we find in the spinal cord?
pseudo unipolar neuron
label
1: granule cells
2: pyramidal cells
Where are pyramidal cell located in matter?
gray matter
What is located in white matter?
axons
Where are purkinje cells located in matter?
gray matter
What are the layers of the cerbellar cortex ?
- molecular cell layer
- purkinje cell layer
- granule cell layer
label the layer of cerebellar cortex
- molecular
- purkinje
- granular
point out the layers of the cerebellar cortex
What is in dorsal horn
interneurons
What is in ventral horn
motor neurons
In alzheimer disease what is disregulated
Tau protein- stablize microtubles
* In AD, they bind and tangle with themselves so the microtubule breaks down
What are the different types of Astrocytes and where are they located
- Protoplasmic: gray matter
- Fibrous: white matter
Where are oligodenrocytes located
white matter
What are the functions of astrocytes?
- nourishment, maintenance and protection
- contribution to barrier that protect neurons: BBB
- neurotransmitters
- reservior of glycogen
- serve as index of CNS toxicity
What is a marker of astrocyte activation
GFAP
Clial fibrillary acid protein (GFAP) what type of intermediate filament
type 3
What happens when we have an issue with GFAP
Tumors of some glial cells but since GFAB is only for astrocytes we can assume
What are microglia
- phagocytic cells, the resident macrophages of the CNS.
- Part of the mononuclear phagocytic system
Where is microglia originated from
Originated from bone marrow monocyte precursor cells.
What is the fxn of microglia
The primary responders to injury of the brain, e.g., multiple sclerosis and trauma.
What is the markers of microglia?
Their markers include complement receptor 3 and major histocompatibility class II (MHC-II)
What does microglial cells interact with?
astrocytes
Oligodendrocytes or schwann cells wrap around one or more axons
Oligo: around several axons of CNA neurons
Schwann cells: one axon
What is the imp of myelin sheath
insulate the axon and enhance the speed of conduction of electrochemical impulses
- Oligodendrocytes in culture develop from an oligodendrocyte progenitor cell by extending processes and forming sheet-like myelin protein-containing protrusions.
- In the presence of neurites, oligodendrocyte progenitor cells extend their processes, and upon contact with a neurite, initiate a wrapping process, subsequently form the compact myelin sheath.
What is the difference in schwann cell and oligodenrocytes
- PNS has overlapping schwann cells
- CNS has astrocyte end foot conacting axon
Where are unmylinated axons located and how does this play with schwann cells
PNS
one schwann cell can enclose many ummyelinated axons but one schwann cell can only enclose one myslinated axon
During development, embryonic axons are surrounded by what?
schwann cells
What is happening in multiple scelerosis?
Macrophages and microglia directly attack myelin (contains myelin basic protein –MBP) stripping fragments of myelin from the sheath encasing nerve axons leaving “naked” demyelinated axons
What is MS
MS is a autoimmune inflammatory disorder associated with localized areas of demyelination in white matter (where axons are in the brain and spinal cord) of the CNS
What is the most common form of gullain-barre syndrome
Acute inflammatory demyelinating polyneuropathy (AIDP) of PNS
What is the cause of gullain-barre syndrome
It is caused by an autoimmune response (bacterial infxn causes molecular mimicry) directed against Schwann cell membranes.
GBS=
MS=
GBS= PNS (swhann cells)
MS= CNS (microglia)
What is the type of epithelium that lines the vasculature
endothelial cells (brain capillary
What is the BBB formed by
BBB is formed by endothelial cells
with tight junctions and glial feet processes of astrocytes
Astrocytes induce capillaries to form what?
zonula occludens (tight junctions)
What does the tight junction from astrocytes do?
limiting diffusion of small molecules
What is the BBB responsible for?
seprarting circulating blood from gluid in the brain where neurons are
Where are Epithelial-like cells of ependyma located
lining of the cerebrospinal fluid (CSF) filled ventricles.
Ependymal does not have what compared to epithelium
No external lamina
What is on ependymal cells?
Cilia and microvilli on the apical surface of the cell.
What are ependymal cells involved in?
Involved in absorbing CSF.
Ependymal cells may be modified within the ventricles to produced CSF. What would they be part of?
Choroid plexus
What are the PNS nerve components
cranial, spinal, peripheral
what is ganglia
collextion of nerve cell bodes
What are specialized nerve endings
motor and sensory
What are examples of sensory receptrors in the skin
- Pacinian corpuscle
- Meissner’s corpuscle
What do merkel cells are what
Merkel’s cells are epidermal cells that function in cutaneous sensation
Where are the locations of pacinian corpuscle and missner’s corpuscle
meissner-> closer to epidermis
PAcinian-> deep in the dermis
what is this
pacinian corpuscles
Where a pacinian corpuscle present and what are they sensitive to
present in the skin and in the connective tissue (CT) of organs deep in the body sensitive to movements (pressure and vibration).
what is this
meissner’s corpuscles
What is the fxn of meissner’s corpuscles
edge detection because closer to surface
In peripheral nerves have connective tissue around what?
- Nerve (N.): epineurium (CT)
- N. Fasicle: perineurium (specialized CT),
- N. fiber: endoneurium (loose CT).
- N. Fasicle contains myelinated and unmyelinated N. fibers.
- Blood–nerve barrier (metabolically active diffusion barrier) is formed by Perineurium, a specialized CT with tight junctions. Endoneurium: endothelium of blood capillaries have tight junctions
*
N.fasicle contains what
myelinated and unmyelinated N.fibers
What is the the Blood-nerve barrier formed by?
PERINEURIUM, a specialized CT with tight junctions
What is endoneurium
endothelium of blood capillaries have tight junctions
Label the PNS cross section
- axon
- myelin
- schwann cell nucelus
point out the layers of peripheral nerve
Each axon surrounded by myelin represents what? and what is that surrounded by?
a single nerve fiber and is surrounded by endoneurium
label
- Schwann cells
- nerve fiber
- and 4. node of ranvier
The lines are axons
The cell bodies (soma) of neurons in PNS are arranded in structures called what?
Ganglia
like how CNS is putjkin and pyrmidal cells
The cell bodies (PNS) have specialized glial cells called what? Where are they located
Satellite cells and surround the outer neuron soma surface
What type of neurons is indorsal root ganglion
sensory pseydo-unipolar neurons
what are the litte dots
satellite cells
Satelliate cells serve as what?
- supportive cells establishing a controlled microenvironment around the neuronal body in the ganglion
- Provide electrical insulation and pathway for metabolic exchanges.
- Their role is analogous to Schwann cells except NO Myelin production
*
How does peripheral nerve injury work (overview)
more specific ???
- After break in neuron which end degenerates? (name what direction)
- What cell is used to fix the broken nerve? What happens if you do not have this cell?
- What happens when the nerve is not successfully regenerated?
- Distal end and in an anterograde fashion
- Schwann cells and if there is no Sch cells then there will be no regeneration
- The axon did not penetrate the cord because there might be too many schwann cells so no regeneration
Can PNS and CNS regenerate nerves
NOOOO, only PNS can
CNS cannot regenerate nerves. Why?
because of nogo proteins since they are negative regulator of neuronal growth in CNA
What does PNS lack to have nerve regeneration
does not have Nogo protein
What can enhance elongation after spinal cord crush injuries?
Nogo antibodies, gene knockouts or decoys
