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67 Cards in this Set
- Front
- Back
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Basic functions of epithelia
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Protection (stratified), absorption (simple), secretion, sensation, contraction.
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What junctions make up terminal bar?
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Zonula occludens (tight junction), zonula adherens, macula adherens (desmosomes)
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What is the function of cilia?
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movement
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Duodenal epithelium are what kind of epithelium?
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Simple columnar
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What is metaplasia?
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a change from one cell type or tissue type to another as a result of physical or chemical stress to a tissue
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What kind of gland is a sweat gland?
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simple coiled tubular
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What are 2 types of neoplasms?
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(abnormal mass of tissue) Benign, Malignant
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What is anaplasia?
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a dedifferentiation of a cell type; in the case of malignancies, more anaplasia = more malignant
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What do the basal lamina separate?
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epithelium and connective tissue
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Where do the intermediate filaments attach to?
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Plaque, plaque to desmosome ?
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What type of gland is the colon?
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simple tubular/goblet cells aka:crypt of lieberkuhn
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Another name for tight junctions?
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Zonula occludents
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Another name for desmosomes?
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Macula adherens
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Are epithelial cells vascular or avascular?
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Avascular. They receive their blood from connective tissue.
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What separates the basal epithelial cells from the adjacent connective tissue?
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Basal lamina *can only be seen on an electron micrograph
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What are the major components of the basal lamina?
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1. type IV collagen 2. laminin- a large glycoproein 3. proteoglycan- heparan sulfate
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Importance of basal lamina?
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-helps determine polarity of cells that rest on it, acts as a boundary between tissue (to the CT)
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What enzyme can digest/break through the basal lamina and what is its clinical relevance?
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type IV collagenase and urokinase-type plasminogen activator, in malignant tumors the cells produce these;can digest through the basal lamina
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What is the basement membrane?
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A combination of the basal lamina (supplied by the epithelium) and an underlying reticular lamina (supplied by the connective tissue)
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What is a desmosome and what is its purpose?
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Patch-like connections between adjacent epithelial cells which serve to hold the cells tightly together. Desmosomes have intermediate filaments associated with them - in the case of epithelium the intermediate filaments are made of cytokeratin and are called tonofilaments
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What is another name for a gap junction?
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Nexus Junction
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What is a gap junction? (nexus junction)
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Open channels (connexons) between adjacent cells. Shown to allow cell-to-cell communication.
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What is the terminal bar?
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In some tissue (ex:intestinal) a complex connecting two apical sides of a cell.
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Zonula occludans- what is it another name for it and what is it?
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Tight junction. It is a tight fusion of the adjacent membranes that serves to prevent luminal materials from diffusing into the intercellular space between adjacent epithelial cells membranes (paracellular route). Completely surrounds cell, like a belt.
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What is the function of Zonula Adherens?
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It functions to hold neighboring cells together. Surrounds entire cell and has actin filaments associated with it.
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What is the function of microvilli?
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Specialized for absorption. Contain a core of microfilaments (actin) which attach to apical side of cell.
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What is the cilia and its functions?
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Longer than microvilli, have cytoskeleton made of microtubules, help with movement.
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What are the microtubules of cilia anchored to?
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to the basal bodies in the apical cytoplasm
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What are stereocilia & where are they found?
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Very long cellular processes, core of microfilaments, no movement function. found in epididymis and inner ear.
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What is transitional epithelium? Give an example.
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Characterized by dome-shaped cells in top layer (undistended) with specialized, thickened apical membranes. Has an ability to adapt to conditions ex: a full bladder
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How would the epidermis of the skin be classified?
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stratified squamous keratinized
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How would the epithelium of the esophagus be classified?
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stratified squamous nonkeratinized
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Epithelium of intesines classification?
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Simple columnar (with brush/microvilli border)
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How would the epithelium of the terminal bronchioles in lungs be classified?
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simple columnar, ciliated
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How would the epithelium of the epididymis be classified?
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Pseudostratified columnar with stereocilia
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What is a gland and what are the two major types?
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A ingrowth of epethilial cells into the underlying connective tissue. There are exocrine glands and endocrine glands (both have many subdivisions)
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What is an exocrine gland?
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Secretes. Two types:
1. SIMPLE - one unbranched duct a. tubular b. coiled tubular c. branched tubular d. acinar 2. COMPOUND - ducts branch repeatedly a. tubular b. branched tubular c. acinar |
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What are the three modes of secretion for exocrine glands?
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Holocrine, Apocrine, Merocrine
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Holocrine Secretion method?
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the entire cell fills with secretory product and then the cell is shed -ex: sebaceous and tarsal glands
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Apocrine secretion method?
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- the apical end of the cell is filled with secretory product and that part of the cell is released -ex: mammary glands
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Merocrine secretion method?
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secretory cells are formed, accumulate near the apical end of the cell and are released by exocytosis -ex: pancreatic acinar cells
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What is dysplasia?
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Changes of size, shape or orientation of cells. Can be precancerous condition.
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Hyperplasia?
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Increased # of cells.
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Hypertrophy?
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Increased cell size. Can be due to puberty (homonal/physiological need) or physical demand ex:exercise increases muscle fiber size in heart
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Hypoplasia?
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Decreased # of cells.
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What is hypotrophy? Another word for it?
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Decreased cell size. Another word=atrophy. Could occur if nerve to mm. is severed, the mm. will atrophy. Also so will the nerve because it has requirments from the mm. as well.
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What does pleomorphism mean?
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Many different sizes and shapes of cells. Can have pleomorphic nuclei as well.
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What is an example of metaplasia?
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In smokers, tissue that was simple oral mucosa, which is normally stratified squamous, nonkeratinized can become keratinized in persons who smoke or chew tobacco. Similarly, simple epithelia can become stratified in response to physical stress. Chronic gastric reflux into lower esophagus causes the stratified squamous epithelium to become a gastric-like epithelium that secretes mucus (Barrett's epithelium)
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What are the two types of epethelial tumors?
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Benign and Malignant.
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Endothelial cells are what type of epithelium?
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Simple squamous
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What is a benign papilloma?
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Tumor that arises from a surface epithelium
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What is a benign adenoma/
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Tumor that arises from a glandular epithelium
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What is a carcinoma?
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an epithelial malignant cancer; many factors affect degree of malignancy; see anaplasia above
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What is adenocarcinoma?
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Malignant cancer arising from glandular tissue.
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What is the normal epithelium of the esophagus?
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Stratified squamous, non-keratinized
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What syndrome results from an absense of dyenin?
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Kartegeners syndrome. People will suffer from frequent respiratory infections. Men become infertile due to immobile sperm.
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What is the important function of dyenin?
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Dyenin arms hold together the doubles of microtubules essential to cilia structure. Without these the cilia cannot function properly
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What is the shape of squamous?
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Flat (width > height)
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What is the shape of columnar?
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Height > width
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What is the shape of cuboidal?
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Height = width
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What does simple mean?
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One layer
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What does stratified mean?
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More than one layer
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What is a transitional cell type?
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A special cell type found in urinary tract.
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What is pseudostratified?
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Looks like more than one layer, but is truely only one layer.
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What cell type is typical of vagina?
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Stratified squamous non-keratinized . Upmost cells are flattened and have nuclei.
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What cell type is typical of epidermis of skin?
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Stratified squamous keritanized. Specific to prevent water loss, upmost cells are dead and contain no nuclei. Are filled with cytokeratin.
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Is metaplasia permanent?
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No. Is usually reversible, and if the stimulus that caused metaplasia is removed, tissues return to their normal pattern of differentiation.
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