Histology - These are definitions for the basic terminology in biology. PDF

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These are definitions for the basic terminology in biology....

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3 types of protein fibers (in matrix): collagen, elastic, reticular adipose tissue (fat tissue): Tissue that stores fat; responsible for insulation, warmth, shock absorption, protection, and major energy reserve apical surface: "free edge"; upper free surface exposed to the body exterior or the cavity of an internal organ avascular: Epithelial tissues is avascular (lacks blood vessels) and so relies on diffusion from blood supply in dermis basal surface: The bottom layer of epithelial tissue that attaches to the basal lamina of the basement membrane Blood is a specialized connective tissue with a unique extracellular matrix: ECM= plasma bone tissue remodels using...: osteoblasts and osteoclasts bone tissue: Most rigid connective tissue, Internally supports body structures, very active tissue, provides place of attachment for muscles of voluntary movement; stores calcium salts; houses bone marrow (which produces red blood cells and stores fat brown adipose tissue: small percentage of adipose tissue; masses of specialized fat cells packed with pigmented mitochondria that produce heat instead of ATP; used for fuel and insulation; can oxidize fatty acid 20X faster than white cartilage contains two major cell types: chondroblasts and chondrocytes cartilage tissue: tough but flexible tissue that absorbs shock and is resistant to tension, compression, and shearing forces; avascular- blood supply comes from perichondrium cell junctions: structures formed by integral proteins in neighboring cells to link cells in a tissue Chondroblasts: immature; actively divide and makes most of the ECM; when surrounded by their own ECM, they mature into inactive chondrocytes; chondrocytes then inhibit small cavities

in ECM (lacunae) cilia: The hairlike projections on the outside of cells that move in a wavelike manner to propel something through a hollow organ; found in the uterine tube and certain respiratory passages Classification according to duct structure: simple glands (not branched), compound glands (branched) Classification by cell layer: Simple epithelia (one layer of cells), Stratified epithelia (two or more layers of cells) Classification by cell shape: Squamous cells, Cuboidal cells, Columnar cells Classification of epithelium according to cell type and tissue layer: Simple squamous epithelium, Simple cuboidal, Simple columnar epithelium, Pseudostratified [falsely layered] columnar epithelium,----- Two types of stratified squamous epithelium: Keratinized, nonkeratinized, Stratified cuboidal, Stratified columnar, Transitional epithelium Collagen: A glycoprotein in the extracellular matrix of animal cells that forms strong fibers (very resistant to tension), found extensively in connective tissue and bone; the most abundant protein (20-25% of all proteins in body) Components of epithelium: apical surface, epithelial cells, basal surface, basement membrane: basal lamina (collagen fibers) components of underlying connective tissue: basement membrane: reticular lamina (reticular fibers) blood vessels compound glands: have a branched duct Connecting and binding: they bind other tissue layers together; found between organs where they anchor them in place connective tissue functions: connecting and binding, support, protection, transportation

connective tissue: A body tissue that provides support for the body and connects all of its parts; ECM is the most prominent feature; binds, supports, protects, and transports substances dense connective tissue: dense regular, dense irregular, elastic Dense Irregular connective tissue: Function: arranged haphazardly able to withstand tension exerted in all 3 directions; provides structural strength

Location: dermis of the skin, fibrous capsules of organs and joints; submucosa of digestive tract dense regular collagenous tissue (parallel collagen fibers): fibers within are very strong because they are oriented in one direction, but they resist tension in only one plane. Found in tendons and ligaments dense regular elastic connective tissue: Mostly parallel-oriented elastic fibers with randomly oriented collagen fibers; allows certain organs to stretch

Found in walls of organs that must stretch to perform their function, such as large blood vessels (aorta) and certain ligaments (ex: spine ligaments) Desmosomes: Composed of integral proteins; Anchoring junctions that prevents cells subjected to mechanical stress from being pulled apart; button like thickenings of adjacent plasma membranes connected by fine protein filaments (epithelia has large# of des.) elastic cartilage: cartilage with abundant elastic fibers; more flexible than hyaline cartilage; found in larynx elastic fibers: stretch and snap back to their original length; can be stretched 1.5X their resting length without breaking endocrine glands: Ductless glands that empty their hormonal products directly into the blood

Epithelial tissue classified based on two criteria: cell shape and number of cell layers epithelial tissue: Sheets of tightly packed cells that line organs and body cavities with little visible ECM epithelial tissue: Tissue that covers outside of the body and lines organs and cavities; act as barriers between body and external environment, and between our organs and fluid filled cavities exocrine glands: secrete chemical substances through ducts lined with epithelial cells that lead either to other hollow organs or out of the body; only local actions extensibility and elasticity: Ability to extend or stretch to return to resting length Extracellular matrix (ECM): composed of substances surrounding the cell in the tissue; 2 main components- ground substance and protein fibers Fibrocartilage: cartilage that contains fibrous bundles of collagen (fibroblasts), such as that of the intervertebral disks in the spinal cord. Functions of ECM: Provides tissue with strength to resist tensile (stretching) and compressive forces

Directs cells to their proper positions within a tissue and holds those cells in place

Regulates development, mitotic activity, and survival of cells in a tissue

Holds cells in proper positions functions of epithelial tissue: protection, immune defenses, secretion, transport into other tissues, sensation gap junctions: small pores in adjacent plasma membranes formed by protein channels; allow

small substances to pass freely between cytosol of the 2 cells; communicate with electrical signals (cardiac muscle) gland: An organ that produces and releases chemicals either through ducts or into the bloodstream. Glands, such as the thyroid, that secrete their products directly into the blood rather than through ducts are classified as __________.: endocrine glandular epithelium: Composed of cells specialized to produce and secrete substances into ducts or into body fluids goblet cells: most common unicellular gland; a column-shaped cell found in the respiratory and intestinal tracts, which secretes mucus. ground substance (majority): shapeless, gel-like; makes up most of the ECM; contains the interstitial or extracellular fluid with water, ions, nutrients, and other solutes (3 macromolecules) Histology is the study of __________.: tissues hyaline cartilage: Packed with Collagen Fibers, Tough but somewhat flexible; Found in: connecting ribs to sternum, respiratory passageways, covering ends of bones at joints. immune defenses: epithelial tissues provide a barrier against invading microorganisms immune defenses: epithelial tissues provide a barrier against invading microorganisms keratinized stratified squamous epithelium: epidermis; apical layers lack nuclei and are dead Keratinized, dead cells are associated with __________.: stratified squamous epithelium loose connective tissue: (AKA: areolar connective tissue) Tissue that binds epithelia to underlying tissues and holds organs in place. Contains collagenous, elastic, and reticular fiber; composed of primarily of ground substance (contains fibers, fibroblasts, and adipocytes); found deep in the epithelium

Membrane Functions: anchors organs in place membranes: Membranes are thin sheets of one or more tissues that line a body surface or cavity Most exocrine glands are multicellular: clusters of secretory cells arranged in different ways muscle tissue: cells that can contract and generate force with little ECM Muscle tissues: Specialized for contraction; Converts chemical energy of ATP into mechanical energy of movement; Primary cell is muscle cell or myocyte; Excitable (ability to respond to electrical or chemical stimulation); Three types: Skeletal, Cardiac, Smooth nervous tissue has two main cell types: neurons and neuroglial cells Nervous tissue: Brain, spinal cord, and nerves; nervous tissue: cells that can generate, send, and receive messages; unique ECM neuroglial cells: Perform various functions that support neuron activities neurons: Capable of sending and receiving messages nonkeratinized stratified squamous epithelium: apical cellular layers retain nuclei; still alive; found in regions subjected to mechanical stress where surface must remain moist; mouth, throat, esophagus, anus, and vagina Osteoblasts: bone building cells; found on outer surface of bone near periosteum Osteoclasts: Bone-destroying/resorbing cells; multinucleated; secrete hydrogen ions and enzymes that catalyze the reaction Osteocytes: mature bone cells protection: bone tissue protects certain internal organs, cartilage and fat tissue provide shock absorption protection: continuous surface that shields the underlying tissues from mechanical stresses and thermal injury

pseudostratified columnar epithelium: simple epithelium that falsely appears as multiple cell layers or stratified; found in the larger respiratory passages in the nasal cavity, where it is ciliated; too thick for efficient diffusion; used for protection reticular fibers: Fibers made of collagen fibers that are very thin and short. Form a tightly woven net (reticul= "net-like") that joins connective tissue to adjacent tissues. reticular tissue: type of loose connective tissue that provides a supportive framework to soft organs, such as lymphatic tissue, spleen, and the liver; populated by reticular fibers produced by surrounding fibroblasts; interweave to form networks that support small structures (ex: blood vessels and lymphatic vessels) secretion: epithelial cells form glands that produce substances such as oil and hormones; these substances are secreted through a duct or into the bloodstream sensation: most epithelia are richly supplied with nerves that detect changes in the internal and external environments simple columnar epithelium: Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliated action. Contain microvilli which increases surface area for absorption Location: nonciliated type lines most of the digestive tract (stomach to anal canal, samll intestine), gallbladder and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus. simple cuboidal epithelium: Relatively thin so substances can diffuse across it rapidly Function: secretion and absorption Location: Kidney tubules; ducts and secretory portions of small glands, ovary surface.

simple glands: single unbranched duct simple squamous epithelium: Single layer of flattened cells; Forms walls of capillaries & air sacs of lungs; specialized connective tissue: cartilage, bone, blood stratified columnar epithelium: Function: protection and secretion

Location: rare in the body; small amounts in male urethra and in large ducts of some glands stratified cuboidal epithelium: (rare in human body) Function: protection lines the ducts of sweat glands, Location: Largest ducts of sweat glands, mammary glands, and salivary glands. Striations are a structural feature associated with some __________.: muscle cells support: bone and cartilage support the weight of the body Synovial membranes line cavities surrounding freely moveable joints: EX: knees, hips, shoulder, and elbows The ECM of blood is known as __________.: plasma The free surface of an epithelial tissue is the __________.: apical surface The major energy reserve in the body is found stored as fat in __________.: adipose tissue tight junctions: Membranes of neighboring cells are held "tightly" together, preventing leakage of extracellular fluid; spaces between are impermeable; prevents macromolecules from passing between the cells (found between the cells of blood vessels) Tissues are structurally more complex than __________.: cells transitional epithelium: function: stretches readily and permits distension of urinary organ by

contained urine

Location: lines the ureters, urinary bladder, and part of the urethra transport into other tissues: because epithelia are selectively permeable barriers, they allow critical nutrients to pass the epithelium and into the blood (ex: small intestine) transport: blood is a fluid connective tissue that is the main medium for transport in the body True membranes...: do not open to the outside of body; EX: Serous membranes (serosae) two types of stratified squamous epithelium: keratinized and nonkeratinized types of cartilage: hyaline, fibrocartilage, elastic types of connective tissue proper: loose, dense, reticular, adipose unicellular exocrine glands: simplest exocrine gland; composed of singular cell EX: goblet cell What do skeletal and cardiac muscle cells share in common?: striations What lubricates movable joints such as the hip, knee, and elbow?: synovial fluid Where is cardiac muscle tissue located?: heart Where is simple columnar epithelium located?: lining of the small intestine Which of the following is constructed of elastic cartilage?: external ear Which of the following is NOT a location of reticular tissue?: tendons white adipose tissue: majority of adipose tissue; White fat, in which excess calories are stored in the body for energy; found deep to the skin (subcutaneous fat) You examine a tissue slide through the microscope and recognize one layer of cells that are mostly tall and elongated. You determine this tissue to be __________.: simple columnar epithelium...