Lab Exam 1 - Histology and Integumentary system Flashcards
Epithelial tissue
Lines and covers organs, creates boundaries between different environments, and forms glands
Epithelia functions
Filtration, absorption, protection, secretion, excretion, and sensory reception
Apical or free surface
Surface where cells are exposed to either external environment or to an internal passageway or cavity
These cells obtain nutrients by diffusion of substances from connective tissue underlying the epithelia
Basal lamina
Epithelium is attached to body via a basal lamina
Located between epithelium and its connective tissue layer
Functions as filter at base of epithelium
Simple epithelium
One layer
Main functions: Diffusion, absorption, filtration, and secretion
Microvilli or cilia on apical/free surface for increased surface area
Stratified epithelia
Composed of more than one layer
Found in areas exposed to abrasion and friction
Main function is protection
Stratified epithelia regenerate from basal cells and move out to replace older cells near apical border
Apical cells
Epithelial cells closest to external environment
Farthest from blood supply and thus atrophy and flatten (in stratified squamous)
Epithelial tissue characteristics
Regeneration: Easily regenerate; Good because many epithelia are exposed to friction or hostile substances
Polarity: Membranes always have one free surface (apical) and its significantly different from the basal surface; Apical surfaces commonly have microvilli and cilia
Cellularity and specialized contacts: Cells fit together to form membranes and are bound together
Supported by connective tissue: Cells are attached to and supported by a basement membrane
Avascularity: Lining epithelial tissues have no blood supply of their own, but instead depend on diffusion of nutrients from underlying connective tissue
Innervated: Supplied by nerve fibers
Basement membrane
An amorphous material secreted partly by epithelial cells and connective tissue cells that lie adjacent to each other with the reticular lamina deeper than the basal lamina
Helps epithelia resist tearing and stretching, reinforces structural integrity, and creates a boundary
Glandular epithelia
Very vascular
Makes up any gland in body
Function is directly related to its location
Simple squamous epithelium
Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm
Allows passage of materials by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae
Located in kidney glomeruli, air sacs of lungs, lining of heart, blood vessels and lymphatic vessels, lining of ventral body cavity, ALVELOI
Unlabelled: https://kitng.me/wp-content/uploads/2016/08/untitled-shoot-2959.jpg?w=1600&h=768&crop=1
Labelled: https://minnstate.pressbooks.pub/app/uploads/sites/39/h5p/content/59/images/image-6375048bd735d.jpg
Simple cuboidal epithelium
Single layer of cube-like cells with large, spherical central nuclei
Secretion and absorption
Located in the walls of ducts and secretory portions of small glands, KIDNEY TUBULES, ovary surface
Unlabelled: https://o.quizlet.com/EXaK0p3iCA5CVEp4-dX3Hw_b.png
Labelled: https://o.quizlet.com/zhdDI8Nr-WGzPKjuuKB6vQ_b.jpg
Simple columnar epithelium
Single layer of tall cells with round to oval nuclei; some cells bear cilia; layers may contain goblet cells (mucus-secreting unicellular glands)
Absorption; secretion of mucus, enzymes and other substances; ciliated type propels mucus by ciliary action
Nonciliated type lines most of DIGESTIVE TRACT, gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, UTERINE TUBES, and some regions of UTERUS
Unlabelled: https://www.flinnsci.ca/globalassets/flinn-scientific/all-product-images-rgb-jpegs/ml1285.jpg
Labelled: https://minnstate.pressbooks.pub/app/uploads/sites/39/h5p/content/39/images/file-63626c3c60cf0.jpg
Stratified squamous epithelium
Thick membrane composed of several layers; basal cells are cuboidal or columnar and metabolically active; surface are squamous; in keratinized type, surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers
Protects underlying tissues in areas subjected to abrasion
Nonkeratinized type forms the moist linings of esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin
Labelled: https://i.ytimg.com/vi/Yy2x3dWN7J4/maxresdefault.jpg
Keratinized: https://vmicro.iusm.iu.edu/hs_vm/images/epi9_kerat.jpg
Non-keratinized: https://study.com/cimages/videopreview/what-is-stratified-squamous-epithelium_01040301_139938.jpg
Pseudostratified ciliated columnar epithelium
Single layer of cells of differing heights; some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting cells and bear cilia
Secretion, particularly of mucus; propulsion of mucus by ciliary action
Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the TRACHEA, most of the upper respiratory tract
Unlabelled: https://microanatomy.net/_Media/application-7_med.png
Labelled: https://anatomytool.org/sites/default/files/16795-384.jpg
Transitional epithelium
Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamous-like, depending on degree of organ stretch
Stretches readily and permits distension of certain hollow organs
Lines the URETERS, URINARY BLADDER, and part of the urethra
Unlabelled: https://images.fineartamerica.com/images/artworkimages/mediumlarge/2/3-urinary-bladder-transitional-epithelium-jose-calvo–science-photo-library.jpg
Labelled: https://ibiologia.com/wp-content/uploads/2019/11/slide_25.jpg
Labelled: https://s3.us-east-2.amazonaws.com/yalehistology/epithelia/transitional_epithelia.jpg
Connective tissues
Provides body with structural support and a means of joining structural components to one another
Functions of connective tissue
Connects, protects, stores reserve energy, insulates body, and transports substances throughout the body
Cells within connective tissue
Cells in connective tissue are widely scattered throughout the tissue
These cells produce and secret protein fibers and a ground substance, that together form the extracellular matrix
Suspended in the ground substance are collagen fibers, elastic fibers, and reticular fibers
Collagen fibers
The strongest fiber
Made up of the protein collagen
Made up of many cross-linked collagen fibrils which is what gives the fibers their strength
Elastic fibers
Largely made of elastin, a protein which forms a branching network in the extracellular matrix to provide stretch and recoil
Connective tissue will stretch to the limits of collagen fibers and then recoil back due to elastic fibers
Reticular fibers
Short, fine fibers made also of collagen but with a different chemistry and form than that of the collagen fibers
Reticular fibers form fuzzy nets that have more give or play
Connective tissue proper
Loose and dense connective tissue
A thick liquid matrix and a variety of cell types
Fibroblasts
Stationary cells that secrete proteins that join other molecules in the matrix to form fibers