96 terms

USCSOM Microanatomy Exam 1

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Niemann-Pick
Lysosomal storage disease effecting Sphingomyelinase; spleen and CNS
Tay-Sachs
Hexosaminidase, recessive disorder; progressive degeneration of nervous system
Gaucher
lysosomal storage disease effecting Beta-glucocerebrosidase.
Spleen and CNS
Glucocerebrosidase accumulates, infiltration of crumpled-paper macrophages. No progressive neurodegeration.
Pompe
Lysosomal storage disease, alpha-1,4 glucosidase, Cardiac & skeletal muscles
Hurler Syndrome
Lysosomal storage disease
alpha-L-iduronidase
skeleton and nervous system
Basophilic
staining readily with basic dyes
stains negatively charged molecules
toluidine blue, methylene blue, alcian blue, hematoxylin
Acidophilic
-Stain w/ an acid dye (Eosin), pink-orange in color
-includes cytoplasm, mitochondria, and some secretory and lysosomal granules, and RBC
-orange G, acid fuschin
metachromasia
The situation where a stain when applied to cells or tissues gives a color different from that of the stain solution; i.e., toluidine blue staining mast cell granules reddish purple.
Orcein
stains elastin
Azan
stains collagen (blue) and basement membrane
Picrosirius Red
collagen specific stain that is observed under polarized light
Nissl
stains rER in neurons
cardiolipin
a special phospholipid found in the inner mitochondrial membrane that contain; blocks ion permeability
cytochrome c
The major cell death event (Bax intracellular pathway) generated by the mitochondria is the release of cytochrome c from the mitochondrial intermembranous space into the cell cytoplasm
Microtubules
dimers of a/b tubulin; polymerization requires GTP and Mg; dynamic instability; movement of organelles and cilia
Actin Filaments
G-actin monomers; polymerization requires ATP and various ions; microvilli, muscles and contractile ring in cell division
Intermediate Filaments
made from a variety of proteins; nonpolar ends; staggered tetramer; involved in desmosomes and hemidesmosomes
Zonula occludens
Occludin and claudin extracellular proteins; ZO intracellular proteins associate with actin filaments; Seals adjacent cells together, controls passage of molecules between them
Zonula Adherens
Cell-Cell interactions with actin filaments; E-cadherin; reinforce zonula occludens; Ca dependent
mesothelium
simple squamous found in serous membranes; pleural, pericardial and peritoneal cavity, covers the visceral organs of those cavities
Simple Cuboidal Location
kidney, small ducts, surface of ovary
Simple Columnar Location
gall bladder, intestine, stomach
Simple Ciliated Columnar Location
trachea
Stratified Cuboidal Location
salivary gland, large ducts; usually only 2-3 layers
Stratified Columnar Location
salivary glands; very rare; basal layer looks cuboidal, but apical layer is columnar
Transitional Epithelium Location
urinary tract; look "ballooned" on the apical surface
Stereocilia
really long microvilli; actin core, ezrin attaches to membrane, no villin in the tips (found in microvilli); found in epididymus, ductus deferens and ear
Motile Cilia
9+2 arrangement; have dynein protein to provide movement
Primary Cilia
immotile, 9+0
Nodal Cilia
motile found in embryo, 9+0 but active rotational movement
Desmosomes (macula adherens)
Cell-Cell interactions involving intermediate filaments; attachment plaque (ID on practical); Desmoplakins, plakoglobins
Hemidesmosomes
Cell-ECM; intermediate filaments to basement membrane; also has attachment plaque;
Connexons
proteins that form gap junctions (6 on each side of the junction)
Plicae
Interdigitating folds in plasma membrane
Increase cell surface area
Fluid and electrolyte transport
Pemphigus
disease where the person develops antibodies against desmosomal proteins
Basal Lamina Components
collagen (IV), laminin, fibronectin, protoglycans
Focal Adhesions
actin cytoskeleton anchorage to basement membrane via integrins
Kartagener's Syndrome
cilia disorder: absence of dynein
Young's Syndrome
cilia disorder: malformed radial spikes and dynein arms
spectrin
cross-links actin filaments
Tropomodulin
capping protein regulating filament length
Taxol
is used in chemotherapy for breast cancer. It stabilizes microtubules, preventing them from depolymerizing
cytochalasins
bind +end, capping actin filament (fungi)
Phalloidin
bind F-actin preventing depolymerization (mushrooms)
Latrunculin
bind G-actin, inducing F-actin depolymerization (sea sponge)
Titin
anchors thick filaments to z-line;
Dystrophin
link laminin to actin filaments
fascia adherens
major part of transverse component of intercalated discs; similar to zonula adherens; end to end adherence of cardiac myocytes
caldesmon
Ca-Calmodulin binding to this protein moves tropomyosin to expose the active sites on SMC actin
Caveolae
pouch-like infoldings that sequester bits of extracellular fluid containing a high concentration of Ca2+ close to the membrane; when calcium channels open here Ca2+ influx occurs rapidly
Duchenne's muscular dystrophy
X-linked frame-shift mutation --< deletion of dystrophin gene --< accelerated muscle breakdown. only effects males
Becker-type muscular dystrophy
defect in dystrophin expression
Myasthenia gravis
individual makes antibodies block AChR
decreased muscle response to nerve stimulation
treat with Ach esterase inhibitors
Excitatory Neurotransmitters
acetylcholine, glutamine, serotonin; open Na channels; initiation of action potential
Inhibitory Neurotransmitters
gamma-aminobutyric acid (GABA), glycine; open anion channels
Schmidt-Lanterman Clefts
areas of retained cytoplasminner collar of Schwann cell cytoplasm between the axon and the myelin
EM Synapse
Non-Myelinated Axon
Glial fibrillary acidic protein
GFAP - unique marker for astrocytes; 80% of adult brain tumors arise from astrocytes
Myelin - CNS vs. PNS
CNS has fewer Schmidt-Lanterman clefts
Little or no cytoplasm present in outer most layer of myelin sheath
No basal lamina in CNS - Myelin of adjacent axons may touch
CNS Nodes of Ranvier larger
Non-myelinated neurons of CNS can be bare (no glial cell)
lipofucsin granules
brown-ish or dark pink (depending on stain) large granules in autonomic ganglia; can be used to distinguish from dorsal root ganglia
Eosinophils
Bi-lobed blood cells; granules (red) are ovoid in EM (crystalline inclusions from major basic protein); reside in tissue of the GI tract
Monocytes
phagocytic WBCs; "horseshoe" shaped nucleus; granules visibile on EM (lysosomal or secretory)
Neutrophils
phagocytic WBCs; multi-lobular nucleus; primary granules (myeloperoxidase and neutrophil defensins); secondary granules (enzymes that degrade antimicrobials); "pus cells"
Mast Cells
basophilic; heparin and histamine containing cells; may have microvilli; Can be ID'd in Loose CT; NOT found in CNS; can be classified by enzyme production (chymase and tryptase in skin; just tryptase in lungs)
Plasma Cells
eccentric nucleus; found in loose CT of GI and respiratory tracts; derived from B lymphocytes; make antibodies; "cart wheel" nucleus visible in EM; can be ID'd in CT; Golgi visible next to nucleus
lymphocytes
smallest WBCs, not much bigger than RBCs; T, B or NK varieties; little cytoplasm visible
Type I Collagen
collagen type found in bones, tendons, ligaments; heterotrimeric (different alpha chains)
Type II Collagen
collagen type found in cartilage; homotrimeric
Type III Collagen
collagen type found in loose CT; homotrimeric
Type IV Collagen
collagen type found in basal laminae; heterotrimeric
Osteogenesis imperfecta
autosomal dominant disorder of connective tissue characterized by brittle bones that fracture easily; effects collagen I
Kniest Dysplasia
Type II Collagen defect:
Short stature, restricted joint mobility,ocular changes leading to blindness, wide metaphyses and joint abnormality seen in radiographs
Ehlers-Danlos
Faulty type III collagen synthesis causing 1) hyperextensible skin 2) tendency to bleed 3) hypermobile joints; blue sclera; can lead to fatal rupture of vessels
Alport's Syndrome
Due to a variety of gene defects resulting in abnormal TYPE IV collagen (basement membrane). Most common form is X-linked. Characterized by hematuria, deafness, and ocular disturbances. CANT PEE, CANT SEE, CANT HEAR.
MMPs
degrade collagen extracellularly; regulated by post-translation and TIMPs
elastic fibers
in loose CT; highly hydrophobic; rich in proline, glycine and alanine; non-glycosylated; involved in intermolecular cross-linking; fibrillin-1
reticular fibers
made of type III collagen; high carb content makes them PAS sensitive; found at the borders of loose CT and epithelium, adipose, glands, lymph nodes
Extracellular Matrix
composed of collagen, elastic fibers, proteoglycans, glycoproteins (laminin and fibronectin), GAGs; none fiber portion known as "ground substance"
Proteoglycan Functions
Functions:
- Structural support, migration, differentiation
- Associate with other ECM components (collagen, laminin, fibronectin)
- Highly hydrated - diffusion of molecules into/out of matrix
- Docking site for growth factors, cytokines, and latent proteases
GAGs
long, unbranched sugar chains (one is either N-acetylglucosamine or N-acetylgalactoseamine); highly negative and hydrophilic
Hyaluronic Acid
GAG found in synovial fluid, vitreous humor and ECM; excellent lubricant
chondroitin sulfate
GAG found in cartilage, bone and heart valves; shock absorbing properties
dermatan sulfate
GAG found in skin, blood vessels, and heart valves; implicated in heart disease
heparin
GAGs in basal lamina, mast cells, basophils; anticoagulant
keratan sulfate
GAG in bone, cartilage and cornea; functions in axonal guidance, cell motility, and cell recognition of ligands
Marfan's Syndrome
Aut-dom, Fibrillin defect (scaffolding for elastin formation)
Connective tissue disorder: skeleton, heart, eyes affected. Tall, long extremities, pectus excavatum, hyperextensive joints
Zellweger syndrome
long fatty acids accumulate due to fatal defect in the biogenesis of peroxisomes in all tissues - affects the liver and brain
Lipid storage diseases
Fabry and Faber's Disease
Mitochondrial Disorders
- Leber's hereditary optic neuropathy - sudden loss of vision in 20-30's
- Pearson marrow-pancreas syndrome - anemia and mitochondrial myopathy in childhood
- Male infertility-flagella movement is impaired
G Protein Coupled Receptors (cAMP)
1) ligand binds to receptor triggering conformational change in G protein
2) GTP replaces GDP in the alpha subunit, leading to activation and dissociation of alpha
3) alpha/GTP complex activates adenyl cyclase leading to cAMP production
4) cAMP is a secondary messenger that can lead to further cascades: PKA (a Ser-Thr protein kinase that phosphorylates a host of enzymes; MAP kinase pathways
G Protein Coupled Receptors (PLC)
1) alphaQ/GTP complex activates phopholipase C enzyme
2) This enzyme hydrolyzes PIP2 splitting it into two secondary messengers: DAG and IP3

IP3 can bind to sER triggering Ca release. DAG stays in membrane, but with Ca can activate protein kinase C, leading to a phosphorylation cascade.
Insulin Receptor
Example of Receptor Tyrosine Kinases

- subunits: two alpha (bind ligand) and two beta (intracellular kinase activity)
- betas autophosphorylate each other (ATP) when ligand binds, and once activated can bind IRS
- PI3K binds to IRS
- PIP2 converted to PIP3
JAK-STAT receptors
associated with tyrosine kinase receptors; kinases bind to receptors after ligand; eventually leads to gene expression; EPO is an example
MAP kinase pathway
involves a series of reactions with Grb2 and Raf leading to activation of nuclear transcription factors
Inhibitors of tubulin polymerization
colchicine, vinblastine, vincristine, nocodazole