Unit1Lec1-Introduction to Biology and Histology of Neurons and Gila Flashcards
1
Q
What are the Anatomical components of the Nervous System?
A
- Central Nervous Systen (CNS)
- Peripheral Nervous System (PNS)
2
Q
What is included in the CNS?
A
- Brain
- Spinal Cord
- Neuronal portions of the eye
3
Q
What is included in the PNS?
A
- Peripheral nerves
- Nerve ending
- Peripheral nerve ganglia
4
Q
What two cells are included in the CNS and PNS?
A
- Neurons
- Glia/Supporting cells
5
Q
List the cells in the brain (CNS)
A
- Neurons
- Glia=Neuroglia (Astrocytes, Oligodendrites, Microglia)
- Endothelial cells (brain capillary)
- Ependymal (Epithelial-like cells)
6
Q
Structure of neuron
A
(Several) dendrites, soma (cell body), axon, synapses
7
Q
What is the function of neurons?
A
Conduct electrochemical signals after impulses are recieved on the dendrites or the cell body.
8
Q
Describe the path of signals in a neuron
A
- Signal is recieved by the dendrites to the cell body
- Continues down the axon (myelinated or unmyelinated)
- Signal then travels to the synapse that makes the connection to other nerves or muscle cells
9
Q
How many types of neurons are there? List them
A
3 types of neurons
1. Bipolar
2. Pseudo-unipolar
3. Multipoplar
10
Q
Describe bipolar neurons and where are they found?
A
- A Single axon emerges from either side of the cell body
- Found in sensory structures (retina, olfactory, epithelium, vestibular & auditory systems)
11
Q
Describe the pseudo-unipolar neurons and where are they found?
A
- A single axon divides a short distance from the cell body
- Two branches: peripheral branch and central branch
- Found in sensory ganglia of cranial and spinal nerves
12
Q
Describe multipolar neurons and what are some examples?
A
- Many dendrites and a single long axon emerge from the cell body
- e.g. Pyramidal neuron of the cerebral cortex
- e.g Purkinje cell of the cerebeller cortex
13
Q
What are the components (5) of the soma (cell body)?
A
- Nucleus
- Nucleous
- Nissl bodies
- Lipofuscin pigment-“age pigment”
- Intermediate filament
14
Q
Describe Nissl bodies
A
Structures that hold ribosomes and rough endoplasmic reticulum (rER)
15
Q
Describe Lipofuscin pigment (“age pigment”)
A
- Staining that shows lysosomes with degradation products (residual bodies)
16
Q
List the characteristics (4) of dendrites
A
- Ramified, spiny, branches extending off the soma
- Increase surface area of neuron for reception
- Contain all proteins/organelles
- NOT myelinated
17
Q
True or False: Dendrites are mylienated
A
False
18
Q
List the characteristics of axons
A
- Singular, straight segment, with no spines
- Responsible for conducting action potential
- No Nissl bodies (e.g axon hillock)
- CAN be myelinated
19
Q
True of False: Axons can be either myelinated or unmyelinated
A
True
20
Q
List the filaments that the neuronal cytoskeleton is made up of
A
- Microtubles
- Intermediate Filaments
- Microfilaments (actin)
21
Q
True or false: the neuronal cytoskeleton are non-membranous organelles
A
True
22
Q
What are microtubules composed of and the relative size?
A
- Tubulin
- 25 nm in diameter
23
Q
What are Intermediate Filaments composed of and their relative size?
A
- Composed of neurofilaments (light, medium, and heavy)
- 10 nm in diameter
24
Q
What are Microfilaments composed of and their relative size?
A
- Actin
- 3-5 nm in diameter
25
Microtubules play a part with which types of proteins in the cytoskeleton?
Motor proteins
26
What is the function of motor neurons
Bidirectional transport of molecules along the axon
27
List the 2 motor proteins
* Kinesin (dimer w/ 2 identical motor heads)
* Dyenin
28
What type of transport does kinesin mediate?
Anterograde
29
Describe Anterograde transport
## Footnote
Done by Kinesin
* Movement of organelles, vesicles and neurotransmitters from soma (- end) to synapase (+ end)
* Fast, Intermediate and Slow
* "away from cell body"
30
What type of transport does Dynein mediate?
Retrograde transport
31
Describe Retrograde transport
## Footnote
Done by Dynein
* Movement of organelles, vesicles and neurotransmitters from synapse (+ end) to soma (- end)
* 1/2 rate of anterograde
* "toward the cell body and termina end of axon"
32
Where else does Dynein play a role?
In cillary and flagellar movement
33
What causes potential entry for harmful substances (e.g. virus)?
Retrograde transport (Dynein)
34
What is need for kinesin and dynein to work?
ATP
35
What cytoskeleton are intermediate filaments a part of and their composition?
* Are a part of Neuronal and Glial cytoskeleton
* Heterogenous group composed of 6 main classes
36
What type of proteins are neurofilaments and where are they found?
* Triple proteins (Light ,Middle, Heavy proteins)
* Found in axon & dendrites of nerve cells
37
List and describe the 3 types of neurofilaments
1. Nestin: neuronal stem cells (nerve cells)- Type VI IF
2. Glial Acidic Fibrillary Protein (GFAP): astrocytes- Type III IF
3. Peripherin: peripherial nerve cells-Type III IF
38
Why do pathologist primarily look at Intermediate filaments?
To determine what cell/type tissue they're working
39
Changes in neurofilaments within the brain are characteristics of what disease?
Alzheimer's disease, which produces neurofibrillary tangles
40
What are microfilaments composed of and list the two types?
* Composed of the protein actin
* G-actin (Globular)- free floating actin in cytoplasm
* F-actin (Filamentous)-polymerized actin
41
Describe the structure of F-actin
* Plus-barbed end=fast growing
* Minus-pointed end=slow growing
42
Describe the mechanism occuring at the synapse
Action potential causes membrane depolarization--->leads to an Influx of Ca+ ions-->causes release of a neurotransmitter
43
List and describe the 4 types of synapses
## Footnote
LOW yield
1. **Axosomatic**- An axon terminal ending on the soma of a neuron
2. **Axoaxonic**- Axon terminal contacting another axon terminal
3. **Axodendritic**- An exon ending on a dendrite
4. **Axospinous**-An axon terminal facing a dendritic spine
44
What are neuroglia
Supporting cells of the nervous system. They are nonconductive but rather offer physical and metabolic support for neurons
45
List the Peripheral (PNS) Neuroglia
1. Schwann cells
2. Satellite cells
46
List the Central (CNS) Neuroglia
1. Astrocytes
2. Microglia
3. Oligodendrocytes
47
Only half the volume of the brain is occupied by neurons. The other half of the brain volume are............
Neuroglia/glia
48
What glia are present during development and what are their function?
* Radial Glia (Bergman glia)
* Serve as "scaffolding" for neurons migrating to their final location in the brain
49
What are radial glia an example of?
The functional interdependence of neuroglial cells and neurons during development
50
What are the two types of astrocytes and where are they found
1. Protoplasmic (gray mattter)
2. Fibrous (white matter)
51
List the functions of Astrocytes
## Footnote
HIGH yield
1. Nourishment, maintenance & protection of neurons
2. Contribute to blood-brain barrier
3. Glycogen stores
4. Index of CNS toxicity
52
Astrocytes interconnect and outline the CNS at the (4):
1. Brain surface (glia limitans)
2. Ependymal lining of the ventricles
3. Synapses
4. Blood vessels
53
Astrocytes form and permit what?
* Desmosomal (tight) junctions & Gap junctions
* Permitting cell to cell transfer of small molecules/ions
54
Astrocyte ________ to injury
React
55
How do astrocytes react to injury?
Increases concentrations of GFAP fibrils at the site of injury forming a **glial scar**
56
How do scientist detect CNS toxicity injuries?
Formation of glial scars by astrocytes
57
What are Microglia?
* Phagocytic cells of the CNS
* The **primary responders** to injury of the brain
## Footnote
e.g. multiple sclerosis and trauma
58
Mircoglia initiate the immune response by....
* Releasing chemoattractants which recruit leukocytes across the BBB
* Contains complement receptor 3 and MHC-II
59
Why do microglial cells and astrocytes interact with each other?
To modulate immune responses
60
Describe the stages of microglia showed in the photo
A. Quiescent (resting) microglia monitor CNS for injury
B. After damage, microglia progressively activate and thicken
C. Severe activation leads to rounding of cells to form macrophages
61
Where are Oligodendrocytes found in the CNS?
White matter (fascicular)
62
List the functions of oligodendrocytes
1. Synthesize myelin sheath
2. Insulates the axons and enhances speed of conduction of electrochemical impulses
3. Wrap around axons of several CNS axons
63
Where are Schwann Cells found?
PNS
64
List the functions of Schwann cells
1. Synthesize myelin sheaths
2. Insulate the axons and enhances speed of conduction of electrochemical impulses
3. Wrap around a single axon in the PNS
65
What do Endothelial cells cover?
Blood vessels
66
What are Non-Brain Fenestrated endothelial cells?
Non-brain fenestrated capillaries have small gaps in plasma membrane
67
What are Brain Non-Fenestrated endothelial cells?
Brain Non-fenestrated capillaries have tight juntions between endothelial cells
68
What forms the Blood Brain barrier
Formed by Endothelial cells with tight junctions+ glial foot processed of astrocytes
69
What do astrocytes induce capillaries to form?
Zonula Occludens (tight junction) limiting diffusion of small molecules
70
What do epithelial cells cover?
Outer surface of the internal organs and the body
71
Functions of epithelial cells of the ependyma
* Movement and absorption of CSF (via cilia and microvilli)
* Bidirectional transport of materials between CSF and neuropil
72
What do ependymal cells line?
The inner surface of the brain ventricles
73
How can ependymal cells be modified? and are a part of?
* Modified within the ventricles to produce CSF
* Part of choroid plexus (CP)
74
1. All of the following are true regarding neuronal dendrites EXCEPT:
A. Ramified, spiny branches
B. Increase surface area of neuron
C. Lack nissl bodies
D. Not myelinated
c. lacks nissl bodies
75
The movement of organelles, vesicles, and neurotransmitters from the synapse of a neuron to the soma (is referred to as ______ transport and is mediated by ______.)
A. retrograde; dynein
B. retrograde; kinesin
C. anterograde; dynein
D. anterograde; kinesin
a. retrograde; dynein
76
3. What is the primary function of epithelial cells in the ependyma?
A. Form the blood brain barrier via tight junctions
B. Synthesize myelin sheath surrounding axons
C. Nourishment and protection of neurons
D. Movement/absorption of CSF
d. movement/absorption of CSF
77
4. An MSP3 student is studying a newfound carcinogen which affects glial cells of the peripheral nervous system. Which of the following glial cells is most likely to be affected by this carcinogen?
A. Astrocytes
B. Schwann cells
C. Microglia
D. Oligodendrocytes
b. Schwann cells
78
5. Which of the following glial cells is the primary responder to injury of the brain?
A. Astrocytes
B. Schwann cells
C. Microglia
D. Oligodendrocytes
c. Microglia
