Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
41 Cards in this Set
- Front
- Back
|
List the steps involved in preparing animal tissue for microscopic viewing |
-specimen must be fixed (preserved) -and then cut into sections (slices) thin enough to transmit light or electrons -finally, the specimen must be stained to enhance contrast
**many dyes consist of negatively or positively charged molecules (acidic and basic stains respectively) that bind within the tissue to macromolecules of the opposite charge |
|
|
Epithelial tissue: 2 forms, roles |
-a sheet of cells that covers a body surface or lines a body cavity -occurs in the body as 1) covering and lining epithelium and 2) glandular epithelium -roles: protection, absorption, filtration, excretion, secretion, sensory reception |
|
|
Special functional and structural characteristics of epithelium |
-polarity: apical surface (upper free surface exposed to the body exterior or the cavity of an internal organ) and a lower attached basal surface; all epithelia exhibit apical-basal polarity, meaning that cell regions near the apical surface differ from those near the basal surface in both structure and function -presence of microvilli (finger like extensions), "brush border," motile cilia -presence of basal lamina which acts as a selective filter that determines which molecules diffusing from the underlying connective tissue are allowed to enter the epithelium, also acts as scaffolding along which cells can migrate -specialized contacts: epithelial cells fit close together to form continuous sheets. Adjacent cells are bound together at many points by lateral contacts, including tight junctions and desmosomes -supported by connective tissue: just deep to the basal lamina is the reticular lamina, a layer of extracellular material containing a fine network of collagen protein fibers. Together the basal and reticular lamina form the basement membrane (which reinforces the epithelial sheet, helping it to resist stretching and tearing forces) -avascular but not innervated: although epithelium is innervated (supplied by nerve fibers), it is avascular (contains no blood vessels) -regeneration: epithelium has high regenerative capacity |
|
|
Simple squamous epithelium |
-single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia -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 (serosae) |
|
|
Simple cuboidal epithelium |
-single layer of cubelike cells with large, spherical central nuclei -secretion and absorption -located in kidney tubules; ducts and secretory portions of small glands; ovary surface |
|
|
Simple columnar epithelium |
-single layer of tall cells with round to oval nuclei some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells) -absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action -nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus |
|
|
Pseudostratified columnar epithelium |
-single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain goblet 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 |
|
|
Stratified squamous epithelium |
-thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the 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 the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane |
|
|
Stratified cuboidal epithelium |
-quite rare in the body, most found in the ducts of some of the larger glands (sweat glands, mammary glands) -typically has 2 layers of cuboidal cells
|
|
|
Stratified columnar epithelium |
-limited distributions in the body -small amounts are found in the pharynx, the male urethra, and lining some glandular ducts -this epithelium occurs only at transition areas or junctions between two other types of epithelia -only apical layer of cells is columnar |
|
|
Transitional epithelium |
-resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch -stretches readily and permits distension of urinary organ by containing urine -lines the uterus, bladder, and part of the urethra
|
|
|
Define gland |
A gland consists of one or more cells that make a secrete (export) a particular product. This product, called a secretion, is an aqueous (water-based) fluid that usually contains proteins
|
|
|
Exocrine vs. Endocrine |
-Glands are classified as endocrine ("internally secreting") or exocrine ("externally secreting") depending on where they release their product -Endocrine: because endocrine glands eventually lose their ducts, they are often called ductless glands. They produce hormones, regulatory chemicals that they secrete by exocytosis directly into the extracellular space. Endocrine glands are structurally diverse, most endocrine glands are compact multicellular organs, but some individual hormone-producing cells are scattered in the digestive tract mucosa and int he brain, giving rise to their collective description as the diffuse endocrine system; their secretions are also varied, ranging from modified amino acids, to peptides, glycoproteins, and steroids -Exocrine: all exocrine glands secrete their products onto body surfaces- the unicellular glands directly (by exocytosis) and the multicellular glands via an epithelium-walled duct that transports the secretion to the epithelial surface |
|
|
Multicellular vs. Unicellular glands |
-glands are classified as unicellular ("one celled") or multicellular ("many celled") based on the relative cell number making up the gland -only important example of unicellular gland if the goblet cell, which is sprinkled in epithelial linings of intestinal and respiratory tracts, produces mucin (dissolves in water to form mucus)
|
|
|
Describe how multicellular exocrine glands are classified structurally and functionally |
-Two basic parts, an epithelium-derived duct and a secretory unit (acinus) consisting of secretory cells. -Multicellular exocrine glands are either simple with an unbranched duct, or compound with a branched duct. -Glands are further categorized by their secretory units as tubular, alveolar, or tubuloalveolar -Mode of secretion: merocrine glands secrete their products by exocytosis as they are produced; holocrine glands accumulate their products within them until they rupture |
|
|
2 main classes of connective tissue; major functions |
-1) connective tissue proper, which includes fat and the fibrous tissue of ligaments, 2) cartilage, 3) bone tissue, and 4) blood -major functions: binding and support, protection, insulation, transportation of substances within the body (blood) |
|
|
Common characteristics of connective tissue |
-Common origin: all connective tissue arise from mesenchyme (an embryonic tissue) -Degrees of vascularity: connective tissues run the entire gamut of vascularity -Extracellular matrix: whereas all other primary tissues are composed mainly of cells, connective tissues are largely nonliving extracellular matrix. Because of its matrix, connective tissue is able to bear weight, withstand great tension, and endure physical trauma and abrasion |
|
|
Structural elements of connective tissue |
-ground substance: the unstructured material that fills the space between cells and contains fibers. It is composed of interstitial (tissue) fluid, cell adhesion proteins, and proteoglycans -fibers: fibers of connective tissue provide support. 3 types of fibers are found in connective tissue matrix, collagen fibers are strongest and most abundant, elastic fibers are long, thin fibers that stretch and recoil easily, and reticular fibers are short, fine, collagenous fibers that branch extensively and form delicate networks that surround small body vessels and support the soft tissue of organs -cells: immature cells are indicated by the suffix "blast," and include- 1) connective tissue proper: fibroblast; 2) cartilage: chondroblast; 3) bone: osteoblast; and 4) blood: hematopoietic stem cell. Mature cells are indicated by the suffix "cyte." Connective tissue is home to an assortment of cells: fat cells, white blood cells, mast cells (detect foreign substances and initiate local inflammatory response), antibody-producing plasma cells, and macrophages (phagocytize foreign materials, dispose of dead tissue cells, central actors in immune system) |
|
|
Classification of connective tissue |
Mesenchyme --> Fibroblast --> Fibrocyte --> Connective tissue proper... 1) loose connective tissue (types: areolar, adipose, reticular) 2) dense connective tissue (types: regular, irregular, elastic)
|
|
|
Areolar (connective tissue proper, loose connective tissue) |
-gel like matrix with all three fiber types; cells: fibroblasts, microphages, mast cells, and some white blood cells -wraps and cushions organs; its microphages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid -widely distributed under epithelia of body, e.g., forms lamina propria of mucous membranes; packages organs; surrounds capillaries |
|
|
Adipose (connective tissue proper, loose connective tissue) |
-matrix as in areolar, but very sparse; closely packed adipocytes (fat cells) which have nuclei pushed to the side by large fat droplet -provides reserve food fuel; insulates against heat loss; supports and protects organs -located under skin; around kidneys and eyeballs; within abdomen; in breasts |
|
|
Reticular (connective tissue proper, loose connective tissue) |
-network of reticular fibers in a typical loose ground substance; reticular cells lie on the network -fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and microphages -located lymphoid organs (lymph nodes, bone marrow, and spleen) |
|
|
Dense Regular (connective tissue proper, dense connective tissue) |
-primarily parallel collagen fibers; a few elastin fibers; major cell type is the fibroblast -attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling for is applied in one direction -location: tendons, most ligaments, aponeuroses (flat, sheet-like tendons which attach muscles to other muscles or to bones) |
|
|
Dense Irregular (connective tissue proper, dense connective tissue) |
-primarily irregularly arranged collagen fibers (on different planes); some elastic fibers; major cell type is the fibroblast -able to withstand tension exerted in many directions; provides structural strength -location: dermis of the skin; submucosa of digestive tract; fibrous capsules of organs and joints |
|
|
Classification of cartilage |
Mesenchyme --> Chondroblast --> Chondrocyte --> Cartilage Types of cartilage: hyaline cartilage, fibrocartilage, elastic cartilage |
|
|
Hyaline Cartilage |
-amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts produce the matrix and when mature (chondrocytes), lie in lacunae -supports and reinforces; has resilient cushioning properties; resists compressive stress -location: forms most of the embryonic skeleton; covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larnx |
|
|
Elastic Cartilage |
-similar to hyaline cartilage in structure, nut more elastic fibers in matrix -maintains the shape of a structure while allowing great flexibility -location: supports the external ear (pinna); epiglottis |
|
|
Fibrocartilage |
-matrix similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate -function: tensile strength with the ability to absorb compressive shock -location: intervertebral discs; pubic symphysis; discs of knee joint |
|
|
Bone (osseous tissue) |
-hard, calcified matrix containing many collagen fibers; osteocytes lie in lacunae; very well vascularized; calcium salt deposits -bone supports and protects (by enclosing); provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation (hematopoiesis) -location: bones |
|
|
Blood |
-red and white blood cells in a fluid matrix (plasma) -transport of respiratory gases, nutrients, wastes, and other substances -location: contained within blood vessels |
|
|
Nervous tissue |
-neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonirritable supporting cells -function: transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity -location: brain, spinal cord, and nerves
|
|
|
Skeletal muscle |
-description: long, cylindrical, multinucleate cells, obvious striations -function: voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control -location: in skeletal muscles attached to bones or occasionally to skin |
|
|
Cardiac muscle |
-description: branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs) -function: as it contracts, it propels blood into the circulation; involuntary control -location: wall of the heart
|
|
|
Smooth muscle |
-description: spindle-shaped cells with central nuclei; no striations; cels arranged closely to form sheets -function: propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control -location: mostly in the walls of hollow organs |
|
|
Cutaneous membrane |
-the cutaneous membrane is your skin -organ system consisting of a keratinized stratified squamous epithelium (epidermis) firmly attached to a thick layer of dense irregular connective tissue (dermis) -dry membrane |
|
|
Mucous membrane |
-mucous membranes line body cavities that open to the exterior, such as those of the hollow organs of the digestive, respiratory, and urogenital tracts -wet or moist membranes, bathed by secretions (mucosa or urine) -most mucosae contained either stratified squamous or simple columnar epithelia -the epithelial sheet is directly underlain by a layer of loose connective tissue called the lamina propria -adapted for absorption and secretion |
|
|
Serous membrane |
-the moist membranes found in closed ventral body cavities -consists of a simple squamous epithelium (a mesothelium) resting on a thin layer of loose connective (areolar) tissue -thin, clear serous fluid lubricates the facing surfaces of the parietal (outside) and visceral (inside) layers, so that they slide across each other easily -pleura: serosa lining the thoracic wall and covering the lungs -pericardium: serosa enclosing the heart -peritoneums: serosa lining the abdominopelvic cavity and viscera |
|
|
Steps of tissue repair |
-Inflammation sets the stage: release of inflammatory chemicals, substances seep into injured area, clotting stops blood loss, scab forms -Organization (first phase of tissue repair) restores the blood supply: blood clot is replaced by granulation tissue, which includes a new capillary bed; proliferating fibroblasts produce growth factors as well as new collagen fibers to bridge the gap; contractile properties pull the wound together; granulation tissue is highly resistant to infection -Regeneration and fibrosis effect permanent repair: surface epithelium begins to regenerate, growing under the scab, which soon detaches; if a wound is extensive or the damaged tissue amitotic, it is repaired only by fibrous connective (scar) tissue; in nonregenerating tissues and in severe wounds, fibrosis totally replaces the lost tissue; over time the fibrous mass shrinks and becomes more compact, scar tissue cannot perform the normal functions of the tissue it has replaced |
|
|
Regenerative capacity of different tissues |
-epithelial tissues, bone, areolar connective tissues, dense irregular connective tissue, and blood-forming tissue regenerate extremely well -smooth muscle and dense regular connective tissue have a moderate capacity for regeneration -skeletal muscle and cartilage have weak regenerative capacity -cardiac muscle and nervous tissue have no functional regenerative capacity |
|
|
Embryonic origin on each tissue class |
-epithelium arises from all three primary germ layers (ectoderm, mesoderm, endoderm) -muscle and connective tissue arise from mesoderm -nervous tissue arises from ectoderm |
|
|
Aging of tissues |
-the decrease in mass and viability seen in most tissues during old age often reflects circulatory deficits or poor nutrition |
