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Flashcards in A & P Tissue CH 6 Deck (45):
1

epithelial tissue or epithelium

is a sheet of cells that covers a body surface or lines a body cavity. functions include protection, absorption, filtration, excretion, secretion and sensory reception.

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epithelial polarity

the membranes always have one free surface called the apical surface, and typically that surface is significantly different from the basal surface.

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simple epithelia

consisting of one layer of cells attached to the basement membrane

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stratified epithelia

consisting of two or more layers of cells

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the general types of epithelial cells based on shape are

squamous (like a fried egg)...cuboidal (like a cube) ..or Columnar (like a column)

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stratified epithelia are named according to the cells at the apical surface of the epithelial sheet, not those resting on the basement membrane

fyi

7

Pseudostratified epithelium

is a simple columnar epithelium (one layer of cells), but because its cells vary in height and the nuclei lie at different levels above the basement membrane, it gives the false appearance of being stratified. this epithelium is often ciliated.

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transitional epithelium

is a rather peculiar stratified squamous epithelium formed of rounded or plump cells with he ability to slide over one another to allow the organ to be stretched. transitional epithelium is found only in urinary system organs such as the bladder. the cells are flattened like true squamous cells when the organ is distended and rounded when the organ is empty

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endocrine glands

lose their surface connection (duct) as they develop this they are referred to as ductless glands. they secrete hormones into the extracellular fluid and from there the hormones enter the blood or the lymphatic vessels that weave through the glands.

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Exocrine glands

retain their ducts and their secretions empty through these ducts either to the body surface or into body cavities. the exocrine glands include the sweat and oil glands, liver, and pancreas

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simple squamous epithelium

single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm: the simplest of the epithelia. -- allows materials to pass by diffusion and filtration in sites where protection is not important- secretes lubricating substances in serosae----kidney glomeruli, air sacs of lungs, lining of heart, blood vessels and lymphatic vessels. lining of ventral body cavity (serosae) ----

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simple cuboidal epithelium

single layer of cube like cells with large spherical central nuclei. --function, secretion and absorption. location, kidney tubules, duct and secretory portions of small glands, ovary surface

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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) -- function, absorption, secretion of mucus, enzymes, and other substances, ciliated type propels mucus (or reproductive cells) by ciliary action.. Location, nonciliated type lines most of the digestive tract (stomach to rectum), gallbladder, and excretory ducts of some glands, cillated variety lines small bronchi, uterine tubes, and some regions of the uterus.

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Pseudostratified columnar epithelium

single layer of cells of differing heights, some not reaching the free surface, nuclei seen at different levels, may contain mucus-secreting goblet cells and bear cilia. function- secretes substances, particularly mucus, propulsion of mucus by ciliary action. location, nonciliated type in males sperm-carrying ducts and ducts of large glands, ciliated variety lines the trachea, most of the upper respiratory tract.

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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. Function, Protects underlying tissues in areas subjected to abrasion. location, Nonkeratinized type forms the moist linings of the esophagus, mouth and vagina....keratinized variety forms the epidermis of the skin, a dry membrane

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stratified cuboidal epithelium

Generally two layers of cube like cells... Function, Protection. Location, Largest ducts of sweat glands, mammary glands and salivary glands

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stratified columnar epithelium

several cell layers, basal cells usually cuboidal, superficial cells elongated and columnar. function, protection, secretion. Location, rare in the body, small amounts in male urethra and in large ducts of some glands

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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. Function, stretches readily and permits distension of urinary organ by contained urine. Location, lines the ureters, urinary bladder and part of the urethra

19

connective tissue

is found in all parts of the body as discrete structures or as part of various body organs. it is the most abundant and widely distributed of the tissue types. they perform a variety of functions but they primarily protect, support and bind together other tissues of the body. ex: bones are composed of connective tissue.. ligaments and tendons (dense connective tissue)

20

Areolar connective tissue

Gel-like matrix with all three fiber types, cells, fibroblasts and macrophages, mast cells and some white blood cells. Function: is a soft packaging material that cushions and protects body organs. Plays an important role in inflammation; holds and conveys tissue fluid. widely distributed under epithelia of body. packages organs, surrounds capillaries.

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adipose tissue (fat)

Matrix as in areolar, but very sparse, closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet. Function: provides insulation for the body tissues and a source of stored food, protects and supports organs. Under skin, around kidneys and eyeballs. within abdomen, in breasts.

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hematopoietic tissue

replenishes the bodys supply of red blood cells

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extracellular matrix

the nonliving material between the cells.. it distinguishes connective tissue from all other tissues. It is produced by the cells and then extruded.

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ground substance

is composed chiefly of interstitial fluid, cell adhesion proteins and proteoglycans. depending on its specific composition, the ground sugstance may be liquid, semisolid, gel like or very hard.

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collagen fibers

fibers that provide support (white) most abundent

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elastic fibers

provide support (yellow)

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connective tissue: reticular

Network of reticular fibers in a typical loose ground substance, reticular cells lie on the network. Function: Fibers form a soft internal skeleton that supports other cell types. including white blood cells, mast cells, and macrophages. Location. lymphoid organs (lymph nodes, bone marrow, and spleen.

28

connective tissue, cartilage, bone, blood

one of 4 main types of adult connective tissue, all of which typically have large amount s of matrix.. connective tissue proper (which includes areolar, adipose, reticular and dense (fibrous) connective tissues) all derive from an embryonic tissue called mesenchyme.

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embryonic connective tissue mesenchyme

embryonic connective tissue, gel like ground substance containing fibers, star shaped mesenchyme cells....function, gives rise to all other connective tissue types....location primarily in embryo

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connective tissue proper: loose connective tissue, areolar

gel like matrix with all three fiber types, cells fibroblasts, macrophages, mast cells and some white blood cells...function, wraps and cushions organs, its macrophages phagocytize bacteria, plays important role in inflammation, holds and conveys tissue fluid.. location, widely distributed under epithelia of body, e.g. forms lamina propria of mucous membranes, packages organs, surrounds capillaries.

31

Cartilage: Hyaline

Amorphous but firm matrix, --collagen fibers from an imperceptible network.. chondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae.. -- function, supports and reinforces, serves as resilient cushion, 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 larynx.

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Cartilage: Elastic

Similar to hyaline cartilage, but more elastic, fibers in matrix. Function, Maintains the shape of a structure while allowing great flexibility. Location, Supports the external ear (auricle) epiglottis

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Cartilage: 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

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Bones (Osseous tissue)

Hard, calcified matrix containing many collagen fibers, osteocytes lie n lacunae. very well vascularized. Function, 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.

35

Blood

Red and white blood cells in a fluid matrix (plasma). Function, Transport of respiratory gases, nutrients, wastes, and other substances. Location, contained within blood vessels.

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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 non-excitable supporting cells. Function, Neurons transmit electrical signals from sensory receptors and to effectors (muscles and glands), supporting cells support and protect neurons. Location, Brain, spinal cord, and nerves.

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Skeletal Muscle

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.

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Cardiac muscle

Branching, striated, generally uninucleate cells that interdigitate at specialized junctions called intercalated discs. Function, As it contracts, it propels blood into the circulation, involuntary control. Location, The walls of the heart.

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Smooth Muscle

Spindle-shaped cells with central nuclei, no striations, cells 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.

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What are the four tissue types?

Epithelial, connective, muscle, neural

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Avascular

Epithelial tissues are supplied by nerves but have no blood supply of their own. Depend on diffusion of nutrients from the underlying connective tissue.

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Connective tissue proper- dense regular

Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. Function: Attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction. tendons, most ligaments, aponeuroses.

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Connective tissue proper- elastic

dense regular connective tissue containing a high proportion of elastic fibers. Function: allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration. walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes.

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connective tissue proper- dense irregular

Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. Function: Able to withstand tension exerted in many directions; provides structural strength. fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract.

44

Skeletal Muscle

Long. cylindrical. multinucleate cells; obvious striations. Function: Voluntary movement; locomotion; manipulation of the environment; facial expression voluntary control. in skeletal muscles attached to bones or occasionally to skin.