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58 Cards in this Set
- Front
- Back
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epithelium arrises from what 3 basic tissue layers
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endoderm, mesoderm, ectoderm
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General characteristics of epithelium
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has a basement membrane, epithelial cells are tightly joined, many modifications to cell surface, form the fx part of certain glandular organs
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Be able to describe difference b/w polarized and nonpolarized epithelial cells and give examples
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polarized: intestinal cells, clear direction and distinction b/w lumen and basement membrane
Non-polarized: endocrine cells, less organized |
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Properties of a basement membrane
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Sheet-like structure , permeable- associated with reticular fibers (net-like)
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Types of epithelium
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simple columnar (SIntes)
Simple Columnar Ciliated (oviduct) Pseudostratified columnar ciliated (respiratory) Stratified epithelium (squamous cells) Transitional epithelium (mesh-like-urinary tract-needs to be flexible) |
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Wedge shaped cells indicate what type of epithelium
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transitional epithelium (mesh-like stretchability)
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Multilayered cells that change from columnar cubical to flat indicate
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stratified epithelium
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What type of cells will you see al the cells attached to the basement membrane and ciliated (think breathing)
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Pseudostratified columnar ciliated epithelium
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cell attachments
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junctional complexs(terminal bars in LM) gap junctions, hemidesmosomes, tightt jnxt, adhesion belts, desmosomes
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Tight junctions other name and functions
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Zonula occludens - constant feature of jnxtional complexes
forms a zone or collar-like junction around cell prevents diffusion of molecules and ions b/w cells |
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adhesion belts other name and function
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zonula adherens
also forms a band around the cell cytoplasmic plaques of actin-binding proteins under the plasmalemma Actin microfilaments (anchored to the dense plaque) Transmembrane glycoprotein (E-cadherin) |
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desmosomes
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macula adherens or focal adhesions between cells
scattered along cel margins has cytoskeletal intermediate filaments anchored to plaques instead of actin |
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gap junctions
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macula communicans- gap jnxs can occur in cells other than epithelia to do cell-cell communication like in the cardiac cell
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hemidesmosomes
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attach cell to basement membrane
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Gap junctions and how they communicate (aka nexus communicans)
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Selective diffusion of some molecules- with membranes that are closesly applied to each other (almost fused) and where the channels and pores span both adjacent membranes - no specific direction depends on concentration gradient to move either direction- important to smooth and cardiac muscle
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What is the major role of a tight junction and if it becomes loose what will happen- what kind of physiological conditions would have loose jnxs
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role- keep material sealed in
loose-material can move more freely and diffuse easier physio conditions- stem cells in brain and new borns |
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Two types of basal surface specializations
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caveolae and pinocytotic vesicles ( types of infoldings and invaginations)
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Apical surface specializations can be differentiated by their
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motility and length
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Microvilli definition and detection
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a non-motile apical surface specialization
many finger like projections from cell surface can only detect individual microvillus with TEM |
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Microvilli structure
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contain actin microfilaments-which anchor at the tip of the microvillus and extend down the terminal web
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Stereocilia
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a type of microvilli (also non-motile) long modified microvili which contain actin microfilaments
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Cilia definition and detection
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a motile apical surface specialization
Resolvable by light microscopy |
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Cilia structure
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contain microtubules anchored to a basal body
9+2 arrangement of doublet microtubles in cilia 9 sets of triplet microtubles in the basal body (similar to centriole) |
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Name an organ you'd be likely to encounter ciliated cells
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GI tract
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Ways to classify epithelial cells
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number of layers (simple vs stratified)
Shape (squamous, cuboidal, columnar, pyramidal) Presence of surface specializations (cilia, microvilli, stereocilia, keratinization) |
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Location/ Structure in the body where stereocilia cells could be found
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male reproductive tract
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How to differentiate simple cells
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squamous- flattened cells with bulging nucleus, cytoplasm hard to distinguish
Cuboidal- cells appear square w/ central nucleus Columnar (columnar with basally placed and elongated nucleus) |
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Where can simple squamous cells be found
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lining lungs body cavities and blood vessels (as mesothelium and endothelium)
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Pseudostratified columnar epithelia
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cells actually contact the basement membrane (top layer of cells usually columnar and ciliated
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Where is transitional epithelium found
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only in teh urinary tract (urothelium)
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Stratified squamous epithelia
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many layers, the outermost of which is squamous in shape, can see cell division occuring
KERATINIZED (cornified) or non keratinized found |
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Keratinized
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lost nucelus where cells change from cuboidal to squamous and may be keratinized
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Layers in the keratinized stratified squamous
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stratum corneum
stratum lucidum stratum granulosum stratum spinosum stratum basale |
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stratum corneum
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soft keratin (tip of cell-near apical surface)
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stratum spinosum
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attached by desmosomes
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stratum basale
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next to basement membrane stem cells located in this layer and where cell division occurs
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In a slide displaying an arteriole could you classify the epithelium on teh slide
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vasco-epithelium and simple squamous (RBC has no nucleus and surrouned by WBC in the arteriole
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Glandular epithelium and functional portion of a gland
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develop from epithelial cells
usually simple cubodial columnar or pyramidal |
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And glandular epithelium that retains connection to the surface is considered
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exocrine (duct)
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And glandular epithelium that is not connected to the surface is considered
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endocrine
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The secretory end piece of the glandular epithelial cell is called
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adenomere
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Types of glands
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unicellular, simple, compound
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unicellular glands
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single secretory cells in teh epitheilial layer GOBLET cell
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Simple gland (duct system in unbranched) would be found
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usually in small glands which is another part of an organ like large intestine
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compound gland
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when the duct system branches (usually in the glands that are organs---pancreas, Brunner's gland in teh duodenum
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Duct status in the endocrine
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Not present -secretion into circulation
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Duct status in the exocrine
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duct is present to the surface of epithelum
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Classification of glands (exocrine types)
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merocrine (exocytosis secretion)
apocrine (pinches off apical part- mammary galnd some sweat) holocrine (entire cell is sloughed as secretory) |
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Ways to classify glands besides endocrine vs exocrine
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Shape (tubular or alveolar)
Type of secretion- serous (protien rich) or mucous (more viscous and glycoprotein rich) |
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The more protein rich a cell or secretion the less or more intense the staining will be
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more intense (dark) so a serous acini stains darker than a mucous acini
more protien-more ribosomes-darker stain |
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Follicular endocrine gland
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Found in thyroid and is poalrized where cells line up nicely
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endocrine glands that are nonpolarized
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pituitary, adrenal, pancreatic endocrine cells
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caveolae
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caveolae
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