Flashcards
L1. Epithelium
Cards in this deck (28)
- 1In what 2 forms do epithelial tissues have? Provide brief description of each.1. Sheets of cells covering external surfaces, lining lumen of various systems (blood vessels, urogenital tracts etc.) and membranes (e.g. pleura, peritoneal, pericardium)
2. Glands - exocrine and endocrine. Originate from epithelial cells - 2Give 4 general characteristics of epithelial cells.1. Close together, with small amounts of intercellular material (i.e. glycosaminoglycan/GAG)
2. Junctional complexes (attachment points) between adjacent epithelial cells hold them together
3. Sits on a basement membrane, separates from underlying CT
4. Avascular, relies on diffusion of substances across BM - 3List all the types of simple epithelia1. Simple squamous
2. Simple cuboidal
3. Simple columnar
4. Pseudostratified columnar - 4Describe simple squamous epithelium including locations and functions- Single layer of flattened cells
- Locations: lining blood and lymph vessels ('endothelium'), lining pleural, peritoneal and pericardial cavities ('mesothelium'), alveoli, loop of Henle
- Function: exchange of gases (alveoli)/fluids (loop of Henle)/nutrients/metabolites - 5Describe simple cuboidal epithelium including locations and functionsSingle layer cuboidal, central nucleus
- Locations: lines tubules/ducts (e.g. pancreas - enzyme production, thyroid follicles - hormone production, etc.)
- Function: Secretory, absorptive, protection - 6Describe simple columnar epithelium including locations and functionsCells are tall, nuclei basal in a single row. On apical surface, may have microvilli (SI) or cilia (oviducts/efferent ductules, small bronchi)
- Locations: SI, stomach lining, uterus and oviducts, inner lining of gall bladder
- Functions: Reabsorption of water from bile, secretion of enzymes and mucus, absorption of nutrients and fluids - 7Describe pseudostratified columnar epithelium including locations and functionsAppears stratified, nuclei at different levels
- Locations: urethra, epididymis, (ciliated) trachea, primary bronchi, auditory tube
- Functions: Secretion and transportation of mucus, lubrication, protection - 8Name the different types of stratified epithelium1. Stratified squamous, nonkeratinised
2. Stratified squamous, keratinised
3. Stratified cuboidal
4. Stratified columnar
5. Transitional - 9Describe stratified squamous (nonkeratinised) epithelium including locations and functionsDeepest cells are cuboidal, superficial cells are squamous and nucleated (hence nonkeratinised)
- Locations: lining mouth, oral pharynx, esophagus, true vocal cords and vagina
- Functions: Protection and secretion of mucus - 10Describe stratified squamous (keratinised) epithelium including locations and functionsSame as nonkeratinised, except surface cells are dead, unnucleated and cytoplasm has been keratinised
- Locations: skin epidermis
- Functions: Protection - 11Describe stratified cuboidal epithelium including locations and functionsSeveral layers of cuboidal cells
- Locations: Lining ducts of sweat glands
- Functions: Absorption, secretion - 12Describe stratified columnar epithelium including locations and functionsDeeper layer is more cuboidal, superficial layers are more columnar
- Locations: Conjunctiva of eye, large excretory ducts of glands, cavernous urethra
- Function: Secretion, absorption, protection - 13Describe transitional epithelium including locations and functionsUrinary system ONLY. Basally is more cuboidal, superficial cells are large and binucleated. Scalloping in empty urinary bladder. Become squamous when bladder is stretched out.
- Function: Protection, distensibility - 14What types of epithelium apical surface modifications are there? List them.1. Microvilli
2. Stereocilia
3. Cilia
4. Flagella - 15Give a brief description of microvilli, including location and functionProjections of cytoplasma
- Location: Striated border of intestinal absorptive cells, brush border of kidney proximal tubules
- Function: (Intestinal epithelia) increase surface area for absorption - 16Give a brief description of stereocilia, including location and functionLong microvilli. Non-motile.
- Location: epididymis, vans deferens, sensory hair of cochlea
- Functions: (epididymis) increases SA for absorption of fluid surrounding sperm, (ear hair cells) signal generation - 17Give a brief description of cilia, including location and functionMotile
- Location: Trachea, bronchi, oviduct
- Function: (trachea) propels mucus, or other structures (ovum by oviduct) using wave-like oscillations - 18Give a brief description of flagella, including location and functionResemble cilia, but are longer, wider and occur as free cells
- Location: spermatozoa
- Function: movement via whip-like action - 19What are the two regions of the basolateral area?1. Lateral plasma membrane
2. Basal plasma membrane
(each has junctional specialisations and receptors for hormones and neurotransmitters) - 20List the types of specialisations on the lateral plasma membraneTerminal bars:
1. Zona occludens
2. Zona adherens
3. Desmosomes/macula adherens - 21Describe the zona occludensAKA Tight junctions
- Prevents movement of membrane proteins from apical domain into basolateral domain
- Fuse plasma membranes of adjacent cells to prevent water-soluble molucles from passing between cells - 22Describe the zonula adherens- Below zona occludens
- Join cell membranes, maintain cell-cell adherence - 23Describe the macula adherensAKA Desmosomes
Spot weld-like junctions:
- Along lateral cell membranes of simple epithelia
- Throughout cell membranes of stratified squamous epithelia (esp. epidermis) - 24Describe the basal laminaBasal surface specialisation
Acellular supportive structure
Mainly Type IV collagen, laminin and proteoglycans
- Location: between epithelium and underlying CT
- Function: supports all epithelium - 25What are the functions of the basement membrane?1. Diffusion barrier: protects against movement of harmful substances into the blood
2. Elastic support for protection against trauma from rough, hard materials - 26What is a gap junction?Spaces between epithelial cells
Allow intercellular communication via ions and small molecules - 27What are some main functions of epithelium?1. Protection of underlying tissues (abrasion, injury, dehydration, invasion)
2. Regeneration (skin wound healing, renewing linings of uterus and GI)
3. Secretion by glandular epithelial cells (hormones direct into blood, acids and enzymes into ducts and hollow organs, sweat onto skin)
4. Detection sensations (taste buds, retina of eye, specialised hair cells in ear) - 28What is a clinical consideration of epithelium?Metaplasia: transformation of epithelium into another form/type
E.g. pseudostratified ciliated columnar (bronchi) undergoing squamous metaplasia (stratified squamous) after heavy smoking - to resist continuous abrasion
Information
- Description
- 2 Year Histology Flashcards on L1. Epithelium, created by B M on 18/06/2017.
- Created by
- B M
- Views
- 1
- Rating