Sept 18 Lecture: Epithilial Tissue Flashcards
What are the four types of tissue in the body
Epithelial, connective, muscle, and nervous.
In general what are tissues made of
They have cells that are related in structure and function, and an extra cellular matrix.
What are the functions of the ECM
They provide the tissue with strength against tensile and compressive forces, they hold the cells in place, and support the function and survival of cells
What are the two main components of the ECM
Ground substance and protein fibers
What is ground substance
Extra cellular fluid made of water, ions, and macromolecules
What are the protein fibers in the ECM
Large polypeptides that are embedded within the ground substance. They have a rope like structure and provide tensile strength
What are the three types of protein fibers
Collagen fibers that resist tension and pressure, elastin fibers that allow stretch and recoil, and reticular fibers which are small collagen fibers that form a scaffold like structure to support the cells and ground substance
What are the three types of junctions in cells
Tight junctions, desmosomes, and GAP junctions
What are tight junctions
Junctions that leave no space in between cells
What are desmosomes
Junctions that increase resistance of the tissue to mechanical stress. In other words they create strong connections
What are Gap junctions
Junctions that allow small substances to move from one cell to another
Where is the ECM found in epithelial tissues
The ECM is the thin layer beneath the cells called the basement membrane.
What type of junction connects epithelial tissues
Desmosomes and tight junctions
What other roles of epithelial tissue around the body
Protection, immune defense, secret, transportation, and sensation
What are the two different layers of the basement membrane
The basil lamina- has collagen fibers and ground substance, and the reticular lamina has reticular fibers and ground substance
How are epithelial tissues classified and name all the classifications
Classifications by cell layers are simple and stratified, in classifications based on the shape of the cell are squamous cuboidal and columnar
What are the two main classifications of epithelial tissue
There’s covering and lining epithelia which covers every internal and external body surface, lines organs in fluid-filled cavities. Next is glandular epithelia which is a tissue that produces and secretes a product with two different types of gland
What are the two main types of gland
Exocrine glands secrete substances into a duct that is lined with epithelial cells, and endocrine glands are made up of specialized epithelial cells that secrete hormones directly into the bloodstream
What is simple squamous epithelium
A single layer of flat cells that allows rapid diffusion of substances like oxygen, carbon dioxide, fluids and ions
What is simple cuboidal epithelium
A single layer of cube shape cells with a large Central nucleus. this is thin enough for rapid substance diffusion
What is simple columnar epithelium
A single layer of rectangular shaped cells with nuclei in basal portion of cell. These cells often have microvilli (small intestine) or cilia (segments of respiratory tract) on apical plasma membrane
What is pseudostratified columnar epithelium
It appears layered because nuclei are at various Heights but it is only one cell layer thick with basal plasma membranes firmly in contact with basement membrane.
How can substances travel across simple epithelia
In parasellular transport substance pass between the cells and intranscellular transport substances enter the cell by active or passive means
What is stratified squamous epithelium
There are two types: keratinized stratified squamous epithelium is found in the skin. The outer layers are dead and lack nuclei and it’s filled with the protein keratin which is tough and resistant to friction. The non keratinized stratified squamous epithelium has outer layers that are alive and retain their nuclei. They protect from mechanical stresses and microorganisms, and are found in the throat mouth esophagus anus and vagina.
What is stratified cuboidal epithe
It lines the ducts of sweatlands
What is stratified columnar epithelium
Layered epithelium where the apical layer is more columnar and the basal layer is more cuboidal. The function is protection some absorption and secretion. It’s found in the mail urethra, the cornea of the eye, and ducks of certain glands like salivary glands
What is transitional epithelium
Epithelium that can expand or shrink to meet the function. There is a cuboidal basal cell layers and dome shaped applications when the tissue is relaxed and cells on the Abaco layer can flatten to allow the tissue to stretch. Found in the urinary system that lines the inside of the kidneys ureters bladder and urethra
What type of epithelia is goblet cells
Glandular epithelia
What are goblet cells
A single cell exocrine gland found in the epithelial layer of the digestive and respiratory tracts that secretes mucus to protect the underlying epithelium
What are merocrine glands
A gland that secretes products packaged into secretory vesicles and releases them by exocytosis into ducts. Some examples are sweat glands salivary glands and exocrine pancreas
What type of gland are most exocrine glands glands
Merocrine glands
What are holocrine glands
They’re a type of exocrine gland that’s used by sebaceous glands in the skin and secretary cells build up products and release when the cell ruptures and dies
What do the exocrine glands in the pancreas do
The secret digestive enzymes into ducts that drain into the small intestine
What are endocrine glands in the panc
Endocrine gland that secrets insulin into the bloodstream
