Cells types and nuerotransmitters

Question 1

Neurons ___.

Injury to axon = ___.

Answer 1

Signal-relaying cells with dendrites (receive input), cell bodies, and axons (send output). Cell bodies and endrites can be seen on Nissl staining (stains the RER, axons don’t have RER).

Injury to axon = Wallarian degeneration. Degeneration distal to injury and axonal retraction proximally. Potential regeneration if in PNS.

Question 2

Astrocytes ___.
If injured ___.
Marker ___.
Derived from ___.

Answer 2

Physical support, repair, K+ metabolism, removal of excess neurotransmitter, component of BBB.

Reactive gliosis in response to injury.
Marker: GFAP.
Derived from neuroectoderm.

Question 3

Microglia ___.
Derived from __.
If HIV infection ___.

Answer 3

Phagocyte/marcophage of CNS. Activated when tissue damage. Not readily discernible by Nissl stain.

Derived from mesoderm (mononuclear origin).
HIV infected microglia fuse to form mutinucleated giant cells in CNS.

Question 4

Myelin __.
Made by ___ in CNS.
Made by ___ in PNS.

Answer 4

Increase conduction velocity (and increase space constant) via saltatory conduction of AP at nodes of Ranvier where there’s high concentration of Na + channels.
CNS - oligodendrocytes.
PNS - Schwann cells.

Question 5

Schwann cells ___.
Derived from ___.
Can be injured in ___ and ___.

Answer 5

Each Schwann cell myelinates only 1 PNS axon.
Derived from neural crest.
Promote axonal regeneration.
Injured in GBS and Vestibular schwannoma (on CN VIII).

Question 6

Oligodendroglia ___.
Derived from ___.
Injured in ___ and __ and ___.

Answer 6

Myelinates axons of CNS, each oligodendrocyte can myelinate many axons. Predominant glial cell type in white matter.
Derived from neuroectoderm.
Injured in MS, multifocal leukoencephalophathy (PML), leukodystrophies.

Question 7

Free nerve endings sense ___ via ___ fiber type(s).

Answer 7

Sense: Pain and temperature
Via:
1. C fibers - slow, unmyelinated
2. A-delta fibers - fast, myelinated

Question 8

Light touch and position are sensed by ___ receptors via ____ fibers and are located ___.

Answer 8

Meissner corpuscles.
Via: Large, myelinated fibers that adapt quickly.
On hairless skin (glabrous)

Question 9

Vibration and pressure are sensed by ___via ___ fibers and are located ___.

Answer 9

Pacinian corpuscles.
Via: Large, myelinated fibers that adapt quickly.
In deep skin layers, ligaments, joints.

Question 10

Pressure, deep touch, and position sense, are sensed by ___via ___ fibers and are located ___.

Answer 10

Merkel discs.
Via: Large, myelinated fibers, adapt slowly.
In finger tips, superficial skin.

Question 11

Pressure, slippage of objects along surface of skin, and joint angle changes are sensed by ___via ___ and are located ___.

Answer 11

Ruffini corpuscles.
Via dendritic endings with capsule, adapt slowly.
In finger tips, joints.

Question 12

Endonuerium ___.

Answer 12

Surrounds single nerve fibers. Inflamed in GBS.

Question 13

Perinuerium ___.

Answer 13

Surrounds fascicle of nerve fibers. Permeability barrier. Must be rejoined for limb reattachment.

Question 14

Epineurium __.

Answer 14

Dense connective tissue that surrounds the entire nerve (fascicles and blood vessels).

Question 15

Acetylcholine synthesized in ___.

Changes in these diseases ___.

Answer 15

Basal nucleus of Meynart. 
Decreases in: 
1. Alzheimer
2. Huntington
3. Parkinson

Question 16

Dopamine synthesized in ___.

Changes in these diseases ___.

Answer 16

Ventral tegmentum, Substantia nigra pars compacta (SNpc).
Decreases in: 
1. Depression
2. Parkinson
Increases in: 
1. Schizophrenia 
2. Huntington

Question 17

GABA synthesized in ___.

Changes in these diseases ___.

Answer 17

Nucleus accumbens.
Decreases in:
1. Anxiety
2. Huntington

Question 18

Norepinephrine synthesized in ___.

Changes in these diseases ___.

Answer 18

Locus ceruleus.
Decreases in: Depression
Increases in: Anxiety.

Question 19

Serotonin synthesized in ___.

Changes in these diseases ___.

Answer 19

Raphe nucleus. 
Decreases in:
1. Anxiety
2. Depression
Inreases in: Parkinson

Question 20

BBB is formed by __.
___ cross slowly by carrier transport.
___ cross rapidly by diffusion.

Answer 20

Formed by:

1. Astrocyte foot processes
2. Basement membrane
3. Tight junctions between nonfenestrated capillary endothelial cells. Destroyed by infarction/neoplasm!

Glucose and amino acids cross slowly by carrier transport.
Nonpolar/lipid-soluble cross rapidly by diffusion.

Question 21

Areas of brain without BBB and with fenestrated capillaries: ___

Answer 21

1. Area postrema - vomitting after chemo
2. OVLT (organum vasculosum of the lamina terminalis ) - osmotic sensing.
3. Neurohypophysis - ADH release.