Intro and Epithelium/integ Flashcards
Cytoplasm contains
Organelles and inclusions
Lipid rafts
Higher levels of cholesterol, saturated FA, glycosphinolipids, and restrict protein movement within the membrane
- Contain various integral and peripheral proteins
- Restrict protein movement
Integrins
Link the cytoskeleton to ECM
-Specifically actin to fibronectin
Glycocalyx
- Glycoproteins and glycolipids
- Fxn in metabolism, cell recognition, cell association, and as hormone receptors
- Glycoproteins project from the micro villi of cells in intestine, include dipeptidases and disaccharidases
Cellular inclusions
-Structures that are not surrounded by a plasma membrane, and they can consist of various materials depending upon cell function and pathophysiology
Types of cellular inclusions
- Crystals
- Pigment Granules (melanin)
- Rosettes (glycogen)
- Lipofuscin (waste)
Mitochondrial matrix
- Enzymes for B-Oxi
- Krebs cycle
Mitochondria of stressed cells release
-Cytochrome C, triggering apoptosis
Peroxisomes
- Usually bud from sER
- Notable for oxidation and detox
- Rich in oxidase and catalase that break down the H2O2-> produce water and oxygen
Free polyribosomes
-Synthesize proteins that localize to the cytosol, cytoskeleton, or become translocated to the nucleus, mitochondria, or peroxisomes
Polysomes on rER
-make proteins that will be secreted or incorporated into membranes or lysosomes
Lysosomes are synthesized in
The Rough ER, enzymes are packaged within the Golgi
Lysosomal contents can be
-excreted or remain in the cell as residual bodies
Lysosomal storage diseases
- Rare congenital disorders caused by mutations in the gene encoding lysosomal enzymes, resulting in substrate accumulation in cells
- Tay-Sachs, Gaucher disease, and Hurler syndrome
Microtubules
- Originate from centriole, the specialized microtubule organizing center found in the centrosome
- Polymers of tubulin
- Movement is accomplished by adding or subtracting tubulin subunits from microtubules
Microfilaments
- Cellular structure and fxn
- Made of actin
- Make up cellular cortex
Intermediate filaments
-Cell structure and fxn
Cytokeratin
- Intermediate fil
- In epithelial cells
Vimentin
- IF
- Mesodermal origin cells
Desmin
- IF
- Muscle cells
-Lamin
- IF
- inside nucleus
Glial fibrillary acidic protein
- glial cells
- IF
Cytoskeleton abnormalities
- Resposible for some blistering diseases of skin
- Epidermolysis bullosa simplex
Epidermolysis bullosa simplex
- Rare congenital disorder caused by mutations in the genes encoding cytokeratins 5 and 15
- Caused by mutation in the plectin gene, an IF cross-linking protein
Adherent cultures
-Anchorage dependent (fibroblast cells)
Contact inhibition
- Monolayer sheets of cells have this
- Grow until they contact neighboring cells then enter G0 (stop growing)
Transformed cells
- Loose contact inhibition
- Re-enter cell proliferation
- Cytopathology strongly correlates to changes in the normal cell cycle
Hallmark of HSV
Marginated chromatin
Three principal characteristics of epithelial tissue
- ) adhere with specialized junctions
- ) exhibits both structural and functional polarity, basal surface attached to basement membrane
- ) creates selective barrier between the external environment and underlying CT
Specific details of simple cuboidal
-Cilia, villi, keratin layer
Stratified cuboidal locations
-Sweat, salivary and mammary glands
Simple columnar locations
- Bronchi
- Uterine tubes
- Uterus
- Smooth forms in GI tract
- Surface of Ovary
- Thyroid follicles
Stratified Columnar Locations
Male urethra
-Ducts of some glands
Pseudostratified columnar special features and locations
- Ciliated tissues lines upper respiratory tract, mucous secretion and ciliary motion
- All the cells are in contact w basement membrane
Umbrella cells in transitional epithelium
-Used to withstand toxic urine
Types of simple squamous
- Endothelium
- Endocardium
- Mesothelium (covers body Cavity)
Simple columnar key features
- Epithelium rests on lamina propria, not basement membrane like pseudostratified
- Basal lamina interposed between cells and CT layer
Stratified cuboidal locations
Sweat glands
- Large exocrine
- Anorectal
Stratified columnar
- Rarest
- Largest ducts of exocrine glands
- Anorectal junction
Microvilli
- Contain actin filaments that are anchored to villin
- Binds myosin I
- Glycocalyx is bound to plasma membrane, visible on LM
Terminal web
Network that contains mainly actin that constitutes the core of microvilli
Stereocilia
- Long microvilli
- In epididymus, proximal ductus deferens, and hair cells of inner ear
- Supported internally by actin which is cross linked by fimbrin
Cilia
Composed of a core of microtubules in 9+2
-Arms contain dyenin
Cell Adhesion molecules
- CAMs
- Lateral domain
Zona occludens
- AKA tight junctions
- Most apical
- Completely encircle cell
- Forms apical compartment
Zonula adherens
- Completely encircle cell
- Allows adherence to next cell
- Actin are found at surface
- Actin, IF, and SPECTRIN
Desmosomes
- Disk shaped
- Cytokeratins are inserted here
Gap Junctions
- Permit direct passage of signaling molecules/electrolytes from one cell to the other
- Vascular and intestinal smooth m, heart muscle
- Connexins
- Calcium ions can trigger gap junction closure at the extracellular surface
- Ca independent gating mech close and open the cytoplasmic domain
Connexin 26 mutation
- Causes congenital deafness
- Inner ear
- Responsible for recirculating K+ in inner ear
Hemidesmosomes
- Cell to ECM junctions found at basal lamina
- composed of integrins
Bullous pemphigoid
- Autoimmune disease where antibodies attack particular pro in hemidesmosomes
- Tiggers mast cells to release eosinophil chemotactic factor
- ECF attract eosinophils which release proteases that break down anchoring filaments
- Large blisters develop
Basal lamina vs External Lamina
- Basal: between epithelium and CT
- External Lamina: term for basal lamina when it forms covering, as for muscle cells or peripheral nerve supporting cells
Lamina propria def
-CT that supports, binds epithelium to nearby structures and provides nourishment
