Microanatomy 2-1 Nervous Tissue

Front 1

CNS compnents:

Back 1

brain, spinal cord

Front 2

PNS components:

Back 2

cranial, spinal, and peripheral nerves

Front 3

Somatic nervous system:

Back 3

Innervation to effector cells/muscles under voluntary control

Front 4

Autonomic nervous system:

Back 4

Provides involuntarily innervation to smooth muscle, heart, & glands
Subdivided into Sympathetic, Parasympathetic, & Enteric

Front 5

CNS supporting cells (4):

Back 5

Microglia, Astrocytes, Epyndemal, Oligodendroglial "MAE-O"

Front 6

PNS supporting cells (2):

Back 6

Schwann, Satellite

Front 7

Multipolar neuron:

Back 7

"classic neuron"; multiple dendrites, 1 axon. motor and interneurons

Front 8

Bipolar neuron:

Back 8

"rare"; 1 axon, 1 dendrite. special sense

Front 9

Pseudounipolar neuron:

Back 9

1 axon divides to 2 as it leaves cell body; 1 division to sensory receptors, other to CNS

Front 10

neuron resting membrane potential:

Back 10

-70 mV

Front 11

what happens to membrane potential when a neuron receives an excitatory stimulus?

Back 11

membrane potential becomes less negative as Na+ flows inside

Front 12

What allows the AP to travel along the axon?

Back 12

Na+ and K+ channels opening

Front 13

What opens when the AP arrives at the end of he axon?

Back 13

Ca2+ channel opens, allowing vesicles with NT to migrate and fuse to the presynaptic membrane. Vesicles then dump contents into the synaptic cleft

Front 14

2 types of synapses:

Back 14

Electrical- primarily found in invertebrates
Chemical- conduction is achieved via neurotransmitters (ACh, 5-HT, GABA etc.)

Front 15

What happens to NTs in the synaptic cleft?

Back 15

bind post-synaptic membrane and either stimulate or inhibit further transmission

Front 16

Excitatory NTs:

Back 16

Acetylcholine, Glutamine & Serotonin

Front 17

Inhibitory NTs:

Back 17

Gamma Aminobutyric Acid (GABA) & Glycine

Front 18

What percentage of NTs is recaptured in a series of uptake pores?

Back 18

80%

Front 19

Paralytics (3):

Back 19

RoCURonium, PanCURonium, VecCURonium; mechanism is to block ACh receptors at neromuscular jnx, preventing muscle contratcion

Front 20

Anterograde axonal transport:

Back 20

Kinesin protein carries molecules from cell body to axons/dendrites in the periphery

Front 21

Retrograde axonal transport:

Back 21

Dynein proein carries molecules from periphery back to cell body

Front 22

Approximatley how fast is anterograde transport of structural elemnts w/ nerve damage?

Back 22

0.2-4mm per day

Front 23

HSV virus high-jacks the _____ transport system, traveling from the skin to the_____ ganglia in oral herpes and the _____ ganglia in genital herpes.

Back 23

retrograde, trigemninal, sacral.

Front 24

Schwann cell:

Back 24

PNS; produce the MYELIN SHEATH around an axon through a process called myelination; cytoplasm of the Schwann cell wraps around the axon,insulating it and allowing for an increase in conduction speed

Front 25

T/F: Each Schwann cell myelinates 1 axon.

Back 25

True; however, it takes many Schwann cells to myelinate an axon.

Front 26

how does myelin assist in AP propogation?

Back 26

It prevents “leakage” of ions from the axon; myelin does not conduct the action potential

Front 27

Node of Ranvier:

Back 27

Point along the axon where Schwann cells meet one another; at this junction the axon is void of myelin but has an increased concentration of Na/K channels thus allowing the AP to continue down the axon

Front 28

Saltatory Conduction:

Back 28

AP 'jumping' from one node of ranvier to the next

Front 29

Satelite cells:

Back 29

PNS; Similar to Schwann cells but found specifically around cell body

Front 30

Oligodendocytes:

Back 30

CNS; Myelin producing cells of the CNS; functionally analogous to Schwann cells, however, Oligodendrocytes myelinate MULTIPLE Axons.

Front 31

Multiple Schlerosis:

Back 31

autoimmune disease targeting Myelin and Oligodendrocytes; Changes in lipid and protein components of myelin resulting in multiple “plaques” found throughout the CNS

Front 32

What is a treatment for MS?

Back 32

immunotherapy

Front 33

Astrocytes:

Back 33

CNS; Provide physical/metabolic support for CNS neurons; The processes of the Astrocyte form tight junctions on nearby capillaries = Blood-Brain Barrier

Front 34

_____ astrocytes are found in the outer gray matter of brain where as ______ astrocytes are found in the inner white matter.

Back 34

protoplasmic, fibrous

Front 35

What do astrocytes allow to cross the blood-brain barrier?

Back 35

Only extremely small, lipid
soluble molecules can cross…
O2/CO2 and of course, alcohol

Front 36

Glioblastoma Multiforme:

Back 36

advanced astrocytoma; most common and aggressive brain tumor in aduls w/ life expectancy <1 year

Front 37

Microglial cells:

Back 37

CNS, Phagocytic; only neuroglial cell that is NOT from the neural tube (embryo);
Monocyte lineage=specialized macrophage-like cell

Front 38

Ependymal cells:

Back 38

Form an epithelium-like lining of fluid filled cavities of the brain and spinal cord

Front 39

Choroid Plexus:

Back 39

Collection of cuboidal/columnar Ependymal cells along with adjacent capillaries that produce Cerebrospinal Fluid (CSF)

Front 40

Endoneurium:

Back 40

Surrounds individual nerve fiber

Front 41

Perineurium:

Back 41

Surrounds nerve fasicle (multiple nerve fibers)

Front 42

Epineurium:

Back 42

Surrounds entire peripheral nerve

Front 43

Peripheral nerve:

Back 43

Consists of a bundle of nerve fibers held together by layers of CT

Front 44

Enteric NS:

Back 44

Controls motility, secretions, and blood flow and can fnx independently of CNS however, effective digestion requires communication with CNS

Front 45

Myenteric (Auerbach's) neurons:

Back 45

The neurons associated with the MYENTERIC plexus are located in between the layers of the Muscularis Externa

Front 46

Submucosal (Meissner's) neurons:

Back 46

The neurons associated with the Submucosal Plexus are located, conveniently, in the Submucosa of the GI wall

Front 47

Hirschsprung's is a ______ disease in which there is a lack of enteric nerves in a segment of colon.

Back 47

congenital; means acquired during development in the uterus, not heriditary. most common cause of intestinal obstruction in neonates

Front 48

What causes Hirschsprung's?

Back 48

Failure of neural crest cells to migrate down into colon; symptoms include constipation, vomitting, abdominal distension

Front 49

Wallerian Degeneration:

Back 49

neuron is damaged/cut/injured-
nucleus moves to the periphery, axon swells and begins disintegrating distal to site of injury. macrophages clear myelin debris.

Front 50

Describe PNS nerve response to injury:

Back 50

Schwann cells line up forming a hollow tube while releasing growth factors to “attract” growing axon which will ultimately penetrate the hollow tube

Front 51

Describe CNS nerve response to injury:

Back 51

-Oligodendrocytes depend on contact with their axons; when contact is lost, they undergo apoptosis.
-Blood-Brain-Barrier also limits macrophage entry, limiting myelin debris removal.
-Astrocytes respond to injury by forming a scar= Reactive Gliosis

Front 52

Will CNS nerves regenerate?

Back 52

not likely.