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57 Cards in this Set
- Front
- Back
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Name the 2 (there are three) predominant types of epithelium.
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Continuous lining of body surfaces: Epithelial Membrane. Invaginated, disconnected cells: Glands. It is not important to know sensory reception now.
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List the embryonic germ layers that give rise to epithelia, with examples.
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1. Ectoderm: skin, mammary glands.
2. Endoderm: gut lining, respiratory lining 3. Mesoderm: serous covering, cardiovascular covering. |
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What is the relationship between epithelia and cancer? Rationalize why.
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90% of cancers are epithelial in origin with >45 years. Most malignancies are epithelial. As the sole barrier cell layer, everything bad hits epi first.
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What are the domains of epithelium? Name some common specializations.
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Apical and basolateral. Apical: microvilli/cilia. Basal: hemidesmosomes/infoldings. Lateral: interdigitations/junctions.
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Characterize the primary difference between the apical and basal domains.
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The apical domain is against a "free" surface, like a lumen. The basal domain adjuts a basement membrane: non-cellular, glycoprotein rich place.
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Define supra- and infra- nuclear. Who doesn't care about those distinctions?
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Supranuclear: between the nucleus and the apical membrane. Infranuclear: between nucleus and basal. Smooth ER doesn't give a flying.
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Define para- and trans- cellular movement.
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Paracellular transport occurs through occluding jxns, while transcellular literally goes through the cell.
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Epithelia covers everybody except what?
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Articular cartilage.
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Epithelium: vascular or avascular? What supply does it possess? How does exchange across the membrane occur?
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Avascular and nonlymphatic, under nonpathological circumstances. It is innervated. Exchange must occur by diffusion.
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Name the intermediate filament found in almost all epithelia. Name the one exception and its location.
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Keratin. Vimentin is found in the lining of blood vessels and the serous cavities. If this is curious, review the chart of intermediate filaments from exam 1.
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Characterize dry and wet epithelium.
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Dry is external. Wet is everywhere else, and must be kept wet or it will die.
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Name the three epithelial membrane types.
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1. Cutaneous: external (to air). Typically keritinized cells.
2. Mucosa: Open to exterior from within. 3. (Serous): Not open to exterior. |
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Characterize the two predominant types of "closed-cavity" epithelial tissue and their locations.
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"Closed-cavity" means serous.
1. Mesothelium of serosa are the 3Ps. Pericardium, pleura, peritoneum. 2. Endothelium line blood and lymph vessels. THEY ARE BOTH MESODERMAL. |
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Do serous epithelial membranes enclose organs?
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No. The organs sit within the membranes akin to the balloon metaphor introduced in Human Structure.
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These prefixes endo and meso are everywhere, how do I avoid getting confused?
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The naming of mature epithelial tissue using endo and meso refers to its MATURE location, while the embryonic naming using endo and meso refers to the germ layer it was born from.
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What do you find in the basement membrane of epithelia?
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Laminin, Type IV Collagen, and a bunch of proteoglycans.
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Where can I find the hormone and neurotransmitter receptors? Why?
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Basolateral membrane. The vasculature of epithelia transmits stuff THROUGH the basement membrane, because, hey, epithelia has NO VASCULATURE of its own.
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Where can I find the Na,K,ATP-ase enzyme? What is it?
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Basolateral membrane.
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Where are those Na and Cl channels Dr. Halm kept talking about?
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Apical membrane. There is a Cl channel in the basolateral membrane too.
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Name the two classification criteria for epithelia?
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The number of layers and the cell shapes.
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What are the layer names, characteristics, and purposes?
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Simple: one sheet of cells, transporters.
Stratified: multiple sheets, protective. |
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If epithelial membranes have multiple layers, how do I know what to classify a membrane as?
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The surface layer cell type defines the membrane type. Nobody below matters.
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What are the cell shape names and characteristics?
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Squamous: flat with a flat nucleus.
Cuboidal: Like a cube, round nucleus. Columnar: Height greater than width. Ovalish nucleus with more supranuclear cytoplasm. |
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2 cell layers times 3 cell shapes = 6 classifications. What are the other two?
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Pseudostratified and transitional. They are SIMPLE.
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Where are simple squamous? What are they called there? What is special about them?
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Simple squamous are in alveoli, blood vessels, P cavities, etc. Remember, blood vessel simple squamous are endothelium. Serous simple squamous are mesothelium. THEY ARE MESODERMAL AND CONTAIN VIMENTIN.
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Simple cuboidal are where and do what?
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In kidneys and secretory ducts. They secrete and absorb.
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Simple columnar are where? Name the two kinds and their characteristics.
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All over the gastrointestine. Height indicates activity.
1. Ciliated: at the apical membrane. In bronchi and oviduct. 2. Nonciliated: HAVE MICROVILLI, in intestine. Contain goblet cells. |
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Name two type of stratified squamous and their locations. What's so special about stratified squamous?
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1. Keritinized: skin. No nuclei in dead layers.
2. Non-keritinized: esophagus and vagina. THE BASAL CELLS OF STRAT SQUAMOUS UNDERGO MITOSIS AND MATURE TO FORM LAYERS. |
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What is unique to stratified cuboidal and stratified columnar?
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They are rare and almost always only two layered.
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What does Dr. Ream want you to remember about stratified epi and why is it helpful?
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STRAT EPI DOES NOT HAVE CILIA OR STEREOCILIA. So you know if you see either of those, it's not stratified and probably pseudostratified.
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What is the most common cell jxn in stratified epi?
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Desmosomes. You can see them as little pink threads under LM.
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Name two types of pseudostratified epi.
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1. Ciliated: in trachea and bronchi. The goblet cells secret mucus.
2. Nonciliated: epidydimis. They will have stereocilia. |
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Where is transitional epithelium located? How can you tell you're looking at it?
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In the urinary bladder and ureters, ONLY. The apical surface is "domed" or rounded.
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How are the two cell layer types renewed?
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1. Simple will undergo mitosis.
2. Stratified have a stem cell population somewhere within that divides in a highly variable manner. |
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What are the stages of common epithelial cancer progression?
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1. Metaplasia: One normal epi type changes into another normal epi type.
2. Dysplasia: The epi membrane begins to break down and mutate. 3. Anaplasia: Mutated epi begins to push through basement membrane. |
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What's a gland? What are the two types?
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A cell or group that secrete substances. Exocrine and Endocrine.
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Define cytokine.
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A cell-to-cell signaling molecule.
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What are the three targets of cytokines?
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Autocrine: Self-signaling.
Paracrine: Nearby cells, no travel. Endocrine: Faraway cells, travel via blood or lymph. |
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What characterizes the parenchyma and stroma of a gland?
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Parenchyma: secretory units and ducts.
Stroma: CT |
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Describe the two types of glands.
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1. Exocrine secrete into ducts through the epithelium into a lumen or air. Think sweat.
2. Endocrine: ductless. Their products diffuse into blood and lymph. Consider adrenal/pituitary/thyroid. |
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Categorize and subcategorize the structural classifications of exocrine glands.
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1. Cell Number: UNI OR MULTICELLULAR.
2. Duct System: SIMPLE OR COMPOUND. 3. Shape of Secreting Unit: TUBULAR, ALVEOLAR, ACINAR, TUBULOACINAR, TUBULOALVEOLAR |
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Acinar and Alveolar both look like little flasks. How can you tell the difference?
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Acinar have narrow lumina, Alveolar have wide lumina.
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What's the naming convention for glands?
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The first word refers to the duct characteristic, all subsequent words refer to the secretory unit alone.
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Categorize and subcategorize the functional classifications of glands.
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1. Cell Involvement: MEROCRINE, APOCRINE, HOLOCRINE.
2. Gland Product: SEROUS, MUCUS, SEBUM, SWEAT, MILK |
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What's an apocrine gland and what's the only one we care about?
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Apocrine secretions take a little cell membrane with them. Mammary glands.
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What's a holocrine gland and what's the only one we care about?
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The cell itself is the secretory product after rupturing. Sebaceous glands.
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Serous vs. mucus
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Watery protein dark-staining granular cells vs. viscous glycoprotein clear-staining cells.
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Mixed seromucous?
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Glands that release both serous and mucus, where serous demilunes appear in LM. Submandibular, sublingual.
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Define sebum.
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Oils. Product of sebaceous glands.
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Define milk.
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Product of mammary glands. IgA, protein, lipids, lactose.
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Define sweat.
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A hypotonic ion-rich secretion. If it has proteins, it's apocrine sweat. If it doesn't, it's eccrine.
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What's the capsule of a multicellar gland?
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Type I collagen in dense, irregular, connective tissue.
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Flow chart of inter and intra
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1. INTERLOBAR ducts through INTERLOBAL septa.
2. INTERLOBULAR ducts through INTERLOBULAR septa. 3. INTRALOBULAR ducts WITHIN the lobules. |
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What do myoepthelial cells look like and how can you remember?
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MYO = muscle. They appear similar to smooth muscle cells.
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What's the embryological origin of myoepithelium?
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Ectoderm.
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Where is myoepithelium?
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Surrounding secretory cells in salivary, sweat, lacrimae, etc.
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What is the purpose of myoepithelium?
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Squeezing, via myosin and intermediate filaments, the secretory products out of their respective glands.
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