Nerve Tissue Flashcards
(66 cards)
1
Q
Another name for neuron cell body? (2)
A
- Soma
2. Perikaryon
2
Q
Classifications of neurons (4)
A
- Multipolar (1 axon and 2 or more dendrites)
- Bipolar (1 dendrite, 1 axon)
- Unipolar/Pseudounipolar (1 process that bifurcates near perikaryon)
- Anaxonic (many dendrites, no true axon, no AP, just regulate neighbors)
3
Q
Where are bipolar neurons found? (3)
A
- retina
- olfactory epithelium
- inner ear
4
Q
What matter do perikarya and axons occur in?
A
- perikarya = gray matter
- axons = white matter
5
Q
Cause and tx for Parkinson’s?
A
- cause = gradual loss via apoptosis of dopamine-producing neurons w/ cell bodies in nuclei of CNS substantia nigra
- tx = L-dopa (dopamine precursor)
6
Q
Histo appearance of soma?
A
- basophilic regions w/ conc RER and polyribosomes
- chromatophilic substances (Nissl bodies)
7
Q
Composition and staining of IM filaments in soma?
A
- Neurofilaments (neurofibrils)
- stained silver
8
Q
Where do most synapses on dendrites occur?
A
Dendritic spines
9
Q
Parts of axon? (3)
A
- PM = axolemma
- contents - axoplasm
- originate from axon hillock in perikaryon
10
Q
Major categories of NTs? (4)
A
- ACh
- AAs like Glu and GABA
- Monoamines (eg seratonin/5-HT and catecholamines/dopamine)
- small polypep’s (eg endorphins and substance P)
11
Q
Network of fine cellular processes emerging from neurons and glial cells?
A
Neuropil
12
Q
Describe features and histo og oligodendrocytes (5)
A
- extend many processes
- produce myelin sheaths
- found only in CNS
- predominant glial cells in white matter (from lipids)
- appear in LM as small cells w/ rounded, condensed nuclei and unstained cytoplasm
13
Q
Describe features and histo of astrocytes (2)
A
- proximal regions reinforced w/ IM filament bundles (glial fibrillary acid protein – GFAP)
- most numerous glial cells in brain
14
Q
Features and location of fibrous astrocytes? (2)
A
- long delicate processes
- abundant in white matter
15
Q
Features and location of protoplasmic astrocytes?
A
- shorter processes
- predominate in gray matter
16
Q
What are astrocytomas?
A
- brain tumors derived from fibrous astrocytes
- express high amt’s of GFAP
17
Q
Is Gly stimulatory or inhibitory?
A
- inhibitory
- inhibits activity b/w neurons in CNS (eg retina)
- opens Cl- channels
18
Q
Function of enkephalin?
A
- neuropeptide
- regulates response to noxious/hamrful stimuli
19
Q
Function of neuropeptide Y?
A
- neuropeptide
- regulates memory
- energy balance
20
Q
Function of somatostatin?
A
- neuropeptide
- inhibits neuron activities in certain parts of brain
21
Q
Function of substance P?
A
- assists w/ pain info transmission
- neuropeptide
22
Q
Function of cholecystokinin (CCK)?
A
- neuropeptide
- mediates satiation
- represses hunger
23
Q
Function of beta-endorphin?
A
- neuropeptide
- fosters feeling of well-being
- prevents pain signal release
24
Q
Function of neurotensin?
A
- neuropeptide
- controls and moderates fx of dopamine
25
How can neuropil be stained?
- gold staining
26
Name some functions of astrocytes (6)
- BBB
- regulate extracell ionic conc's, esp K+ lvl's
- extend fibrous processes w/ perivasc feet that cover capillary endothelial cells and modulate blood flow
- glial limiting membrane
- proliferate to form astrocytic scar and fill tissue defects
- comm w/ each other via gap junctions
27
Tissue components of Alzheimer's?
- neurofibrillary tangles from tau proteins
| - neuritic plaques from beta-amyloid protein
28
Features and histo of ependymal cells? (5)
- columnar/cuboidal cells that line ventricles of brain and central canal of SC
- cilia on apical ends to facilitate CSF movement
- microvilli for absorption
- joined by apical junctional complexes
- no basal lamina
29
Features and histo of microglial cells? (3)
- immune defense in CNS
- originate from bone marrow
- small, dense, elongated structure
30
Features of Schwann cells? (3)
- aka neurolemmocytes
- counterparts to oligodendrocytes in PNS
- form myelin sheaths
31
Features of satellite cells? (2)
- form thin glial layer around each neuronal cell body in PNS ganglia
- regulate microenvironments
32
Where are pyramidal neurons found? Afferent or efferent?
- cerebral cortex
| - efferent
33
3 layers of cerebellar cortex?
1. thick outer molecular layer w/ neuropril
2. thin middle layer w/ large Purkinje neurons
3. thick inner granular layer w/ small, dense neurons
34
Features of dura mater? (2)
- dense irregular connective tissue
| - outer periosteal and inner meningeal layers
35
Features of arachnoid mater? (5)
- sheet of connective tissue contacting dura mater
- sys of loosely arranged trabeculae (collagen and fibroblasts) cont w/ pia mater
- subarachnoid space w/ CSF surr trabeculae
- avasc connective tissue
- hold arachnoid villi, where CSF absorbed into venous sinuses
36
Features of pia mater?
- sep'd from neurons by thin layer of astrocytic processes (GLM)
- covers perivasc spaces that penetrate CNS w/ blood vessels
37
Where is BBB not present? (3)
- hypothalamus
- posterior pituitary
- choroid plexus (CSF production)
38
Histo of choroid plexus? (3)
- highly vasc tissue
- cuboidal ependymal cells
- holds ions and lymphocytes but little protein
39
Where are Schmidt-Lanterman (myelin) clefts found?
- b/w major dense lines of membranes
40
Nerve org of PNS?
- thin layer of endoneurium surr external lamina of Schwann cells w/ reticular fibers, fibroblasts, and capillaries
- Schwann cells/endoneurium bundled together as fascicles by perineurium sleeve, maintain blood-nerve barrier
- epineurium is deep, irregular fibrous coat externally
41
What proteins control neural plasticity?
Neurotrophins
42
What is chromatolysis?
- nerve regeneration
| - axonal outgrowth
43
What is a neuroma? (3)
- extensive gap b/w proximal and distal segments of cut peripheral nerves
- newly growing axons may form swelling (neuroma)
- source of spont pain
44
Where are pseudounipolar neurons found?
Dorsal root ganglion
45
What organelles are Nissl bodies?
RER
46
What organelles will not be found in axons? (2)
- Golgi complex
| - Nissl bodies
47
What particles undergo fast axonal transport? (2)
- vesicles
| - mitochondria
48
What particles undergo slow axonal transport? (2)
- cytoplasmic proteins
- cytoskeletal proteins
- for assembly of MTs and neurofilaments
49
What matter are fibrous and protoplasmic astrocytes each found in?
- fibrous = white matter
| - protoplasmic = gray matter
50
What cells are primary site of HIV-1 infection in CNS?
Microglia
51
Key diff's b/w oligodendrocytes and Schwann cells? (2)
- oligo's = CNS while Schwann = PNS
| - 1 oligo can myelinate several neurons but each Schwann can only myelinate one axon
52
What type of nerves are found in lateral horn of spinal cord?
Pre-ganglionic sympathetic neurons
53
Where is choroid plexus located?
- in roof of 3rd/4th ventricles
| - walls of lateral ventricles
54
Where are astrocytes (GFAP-pos cells) found in neural tissue?
Gray matter
55
In the choroid plexus H2O from capillaries is transported dir into CSF by what structure?
Ependyma
56
What is a characteristic of connective tissue layer surr ind fascicles in large peripheral nn?
Important as part of blood-nerve barrier in nerve
57
Key component of regeneration of peripheral axons after nerve injury?
Schwann cell proliferation
58
What are the principal NTs in PNS?
ACh and noradrenaline
59
T/F: Axons can branch and form synapses both along their course and at their ends
True
60
What cell layers surr fascicles of nerve fibers w/i a nerve?
Perineurium
61
Beginning at the axon membrane, name the layers of connective tissue that build up to make a peripheral nerve.
Myelin sheath --> Endoneurium --> Perineurium --> Epineurium
62
Specific function of ependymal cells in CNS
Produce CSF
63
What does central canal of spinal cord contain?
CSF
64
What class of neurons exist in dorsal root ganglion?
Pseudounipolar
65
When can Schwann cells assoc w/ more than 1 axon?
For unmyelinated axons in PNS
66
Type of collagen that comprises endoneurium?
Type 3 collagen
