Epithelia (struc.) Flashcards
- Definitions
* Cells > Tissues > Organs > Systems (CTOS)
- Tissues = an aggregation of ? and ? substances with a ? purpose
- The organs of the body are made up of only four basic types of tissue:
o ? tissue o ? tissue o ? tissue o ? tissue
- Definitions
* Cells > Tissues > Organs > Systems (CTOS)
- Tissues = an aggregation of cells and extracellular substances with a common purpose
- The organs of the body are made up of only four basic types of tissue:
o epithelial tissue o connective tissue o muscle tissue o nervous tissue
Three Types of Epithelium
- ? (surface) epithelia form sheets that cover body surfaces or line luminal organs, tubular structures, and body cavities.
- ? epithelia have specialized cells that synthesize, store and ? various products.
- Special epithelia contain ?; found in the skin, ?, and on the tongue; (in nose and eyes there are ?).
Three Types of Epithelium
- lining (surface) epithelia form sheets that cover body surfaces or line luminal organs, tubular structures, and body cavities.
- glandular epithelia have specialized cells that synthesize, store and release various products.
- Special epithelia contain sensory nerve endings; found in the skin, ears, and on the tongue; (in nose and eyes there are modified NEURONS).
Functions of Epithelial Tissues (PFCDASS)
- Protection (the epidermis protects from mechanical ?/injury, harmful chemicals, invading microbes, and excessive loss of ?.)
- ? reduction (smooth endothelial cells line the entire circulatory system to reduce friction between blood and walls of the blood vessels and of heart chambers)
- ? (ciliated respiratory epithelium assists in removing dust particles/foreign bodies from air passages)
- Diffusion (? of capillaries promotes the diffusion of gases, liquids and nutrients)
- Absorption (certain epithelial cells lining the small intestine absorb ? from digested food)
- Secretion (specialized epithelial tissue secretes chemical substances such as ?, hormones and ? fluids)
- Sensation: specialized epithelial tissue containing sensory nerve endings convey sensations from the skin, ears, and the tongue
Functions of Epithelial Tissues
- Protection (the epidermis protects from mechanical abrasion/injury, harmful chemicals, invading microbes, and from excessive loss of water.)
- Friction reduction (smooth endothelial cells line the entire circulatory system to reduce friction between blood and walls of the blood vessels and of heart chambers)
- Cleaning (ciliated respiratory epithelium assists in removing dust particles/foreign bodies from air passages)
- Diffusion (endothelium of capillaries promotes the diffusion of gases, liquids and nutrients)
- Absorption (certain epithelial cells lining the small intestine absorb nutrients from digested food)
- Secretion (specialized epithelial tissue secretes chemical substances such as enzymes, hormones and lubricating fluids)
- Sensation: specialized epithelial tissue containing sensory nerve endings convey sensations from the skin, ears, and the tongue
Relevance
- Basic understanding of tissue organization, development and functioning.
- Essential to understand as:
– ? histology: many ? and all ?
have an ? component.
– ? / neoplasia : ?.
** Relevance
- Basic understanding of tissue organization, development and functioning.
- Essential to understand as:
– systemic histology: many organs and all glands have an EPITHELIAL COMPONENT.
– tumors / neoplasia : terminoogy
Characteristics of Epithelium
- Supported by ? tissue
- Avascular or vascular?
- ? membrane present
- Epithelial cells are ?
- Epithelial cells are ?
Characteristics of Epithelium
- Supported by connective tissue
- Avascular
- basement membrane present
- Epithelial cells are cohesive
- Epithelial cells are polarised
epithelial cells have:
list 3 surfaces
Lining Epithelia
SIMPLE SQUAMOUS Epithelium:
- Composed of ?, ? cells, with a “** V IMP!!! ? to ? (shape) nucleus , often? located.”
- Common locations:
– lining of ?, generally called ? (pleural, pericardial and peritoneal);
– ** ? walls in lungs; **
– Inner lining of blood vessels and lymphatic vessels; called ** ? **.
NOTE: H&E = ? & ? stain – the most common type of histological staining
apical surface
lateral surface
basal surface
Lining Epithelia
SIMPLE SQUAMOUS Epithelium:
Composed of flat, elongated cells, with a “** V IMP!!! round to oval (shape) nucleus , often CENTRALLY located.”
Common locations:
– lining of body cavities, generally called MESOTHELIUM (pleural, pericardial and peritoneal);
– ** alveolar walls in lungs; **
– Inner lining of blood vessels and lymphatic vessels; called ** endothelium **
sidenote: simple squamous mostly just lines the lining and alveolar wall IN LUNGS
Lining epithelia
SIMPLE COLUMNAR Epithelium
- ?, narrow cells with ? nuclei located near the ? of the cell.
- Example of simple columnar epithelium:
– Lining the luminal surface of ?, small and large ?, ?
Lining epithelia
SIMPLE COLUMNAR Epithelium
- tall, narrow cells with ovoid nuclei located near the base of the cell.
- Example of simple columnar epithelium:
– Lining the luminal surface of stomach, small and large intestine, endothelium
H&E = hematoxylin and eosin stain - most common type of histological staining
SIMPLE COLUMNAR CILIATED (C) Epithelium:
(a) diagram and (b) lining of oviduct stained with Azan stain
pic: BM cilia G goblet cell
PSEODOSTRATIFIED EPITHELIUM
- Composed of a single layer of ? shaped and ? cells.
- *** All cells touch the ? membrane, but not all of them reach the ? surface.
- Can be ? (?) ***
- Examples of pseudostratified
epithelium include:
– ? cavity, ? tract
PSEUDOSTRATIFIED EPITHELIUM
- Composed of a single layer of irregularly shaped and sized cells.
- *** All cells touch the basement membrane, but not all of them reach the apical surface.
- Can be ciliated (?) ***
- Examples of pseudostratified
epithelium include: (NUrt)
– nasal cavity, upper respiratory tract
NUrt
Example: Pseudostratified Ciliated Columnar Epithelium lining the Trachea
When things go wrong with cilia:
* ? due to the absence of cleansing activity of cilia in upper air ways
Example: Pseudostratified Ciliated Columnar Epithelium lining the Trachea
When things go wrong with cilia:
* chronic respiratory infection due to the absence of cleansing activity of cilia in upper air ways
STRATIFIED SQUAMOUS EPITHELIUM
- Epithelium composed of one or several? layers of cells
- ? cells determine the name thus, the superficial cells have a ? shape
- There are 2 types of squamous epithelium:
– ? (cornified)
– ?
STRATIFIED SQUAMOUS EPITHELIUM
- Epithelium composed of several layers of cells
- superficial cells determine the name thus, the superficial cells have a squamous shape
- There are 2 types of squamous epithelium:
– keratinized (cornified)
– non-keratinized
(note: in above pic, many layers and not just one like the previous ones)
TRANSITIONAL Epithelium (UROthelium)
- Lines ? passages.
Example: ?
*The superficial cells have a specialized PM providing an ? barrier between ? and ? fluids.
When bladder is relaxed then does it appear cuboidal or flattened (statified squamous epithelium)?
ans in pic
Epithelial Repair
- Epithelial cells are ? lost and replaced
- ? cells are present which have high ? potential
- Location of stem cell varies depending on epithelial ? and ?
Cells are pushed by the new layers away from the BM and are shed off
Stem cells are located in a “ *** ? “ cell layer (stratum ?)
Epithelial Repair
- Epithelial cells are constantly lost and replaced
- stem cells are present which have high mitotic potential
- Location of stem cell varies depending on epithelial type and function
Cells are pushed by the new layers away from the BM and are shed off
Stem cells are located in a “ *** BASAL “ cell layer (stratum basale)
Exfoliative cytology
- harvesting cells shed from ? tissues, from ? membranes or found in body ? and examining them under a ?
examples:
- skin surface cytology (differential diagnosis of dermatitis)
- urine sediment analysis
- vaginal smear analysis (bitches): type of epithelial cells observed indicates phase of estrus cycle
- fine needle biopsy of masses
(pic: look at words in brakcets)
Exfoliative cytology
- harvesting cells shed from surface tissues, from mucous membranes or found in body liquids and examining them under a microscope
B. Glandular Epithelia
Criteria of classifications:
- ? of cells in the gland (unicellular or multicellular)
- Shape of ? and shape of ? units (adenomeres)
- Type of ?
- ? of secretion
B. Glandular Epithelia
Criteria of classifications:
- number of cells in the gland (unicellular or multicellular)
- Shape of duct and shape of secretory units (adenomeres)
- Type of product
- mode of secretion
Unicellular Glands
- Found in epithelial ? (similar to squamous) and ? of intestine and in the epithelial lining of the ? tract.
- Example:Goblet cells have a “?” – goblet shape due to the presence of abundant ? in the apical part of the cell
Unicellular Glands
- Found in the epithelial lining (similar to squamous) and glands of the intestine and in the epithelial lining of the respiratory tract.
- Example: Goblet cells have a “CUP” – goblet shape due to the presence of abundant mucinogen granules in the apical part of the cell
refer to pic: Mucinogen granules stain ? (color?) with Alcian blue.
Simple columnar epithelium (found in luminal surface of stomach, small and large intestine, gall bladder) of the colon with goblet cells
Multicellular glands are modified epithelia
- ? : straight or coiled (sweat gland, stomach glands, intestinal glands)
- ?: pie‐shaped, small lumen (pancreas, salivary glands)
- ?: larger luminal space (mammary gland, prostate, sebaceous glands)
Multicellular glands are modified epithelia
- tubular : straight or coiled (sweat gland, stomach glands, intestinal glands)
- acinar: pie‐shaped, small lumen (pancreas, salivary glands)
- alveo”lar”: “lar”ger luminal space (mammary gland, prostate, sebaceous glands)
SIMPLE TUBULAR GLAND (refer to pic)
Acinar shape
Acinar shape corresponds to a ? (shape) secretory unit
Alveolar shape
Alveolar shape corresponds to a bigger ? space
Acinar shape
Acinar shape corresponds to a rounded (shape) secretory unit
Alveolar shape
Alveolar shape corresponds to a bigger luminal space
Compound glands & Parenchyma
The collective of ? units and ? of a ? gland is termed PARENCHYMA;
the connective tissue elements comprise the ?.
Large glands are divided into ?.
These are further subdivided by connective tissue into ?.
Compound glands & Parenchyma
The collective of secretory units and ducts of a compound gland is termed PARENCHYMA;
the connective tissue elements comprise the stroma.
Large glands are divided into lobes
These are further subdivided by connective tissue into lobules
