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Simple squamous epithelium

0 Single layer of flattened cells with disc shaped central nuclei and sparse cytoplasm, the simplest of epithelia .

0 allows materials to pass by diffusion and filtration in sites where protection is not important, secretes lubricating substances in serosae

0 Kidney glomeruli, air sacs of lungs, lining of heart, blood vessels and lymphatic vessels, lining of ventral body cavity

Simple cuboidal epithelium0 Single layer of cube-like

cells with large, spherical central nucleus

0 Secretion and absorption

0Kidney tubules, ducts and secretory portions of small glands, ovary surfaces

Simple columnar epithelium0 Single layer of tall cells with

round to oval nuclei, some cells bear cilia, layer may contain mucous-secreting unicellular glands

0 Absorption, secretion of mucus, enzymes and other substances. Ciliated type propels mucus by ciliary action

0 Nonciliated type lines most of the digestive tract(stomach to anal canal), gallbladder, and excretory ducts of some glands. Ciliated type lines small bronchi, uterine tubes and some regions of the uterus

Pseudostratified columnar epithelium

0 single layer of cells of differing heights, some not reacing the free surface, nuclei seen at different levels; may contain mucus-secreting cells and bear cilia

0 Secretion, particularly of mucus; propulsion of mucus by ciliary action.

0 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

0 Thick membrane composed of several cell layers, basal cells are cuboidal or columnar and metabolically active, surface cells are flattened, in the keratinized type, the surface cells are active in mitosis and produce the cells of the more superficial layers

0 Protects underlying tissues in areas subjected to abrasion

0 Nonkeratinized type forms the moist linings of the esophagus, mouth and vagina. Keratinized variety forms the epidermis of the skin, a dry membrane.

Transitional epithelium0 Resembles both stratified

squamous and stratified cuboidal, basal cells cuboidal or columnar, surface cells dome shaped and squamouslike, depending on degree of organ stretch

0 Stretches readily and permits distension of urinary organ by contained urine

0 Lines the ureters, urinary bladder and part of the urethra

Connective, Muscle & Nervous Tissue:

Embryonic Connective Tissue:Mesenchyme

0Gel-like ground substance contains fibers; star-shaped mesenchymal cells.

0Gives rise to all other connective tissue types.

0 Primarily in embryo

Areolar (loose c.t.)

0wraps and cushions organs, macrophages phagocytize bacteria; plays important role in inflammation: holds and conveys tissue fluid.

0Widely distributed under epithelia of body.

Adipose (loose c.t.)

0 Provides reserve fuel; insulates against heat loss; supports/protects organs.

0Under skin; around kidneys and eyeballs; within abdomen; in breasts.

Reticular (loose c.t.)

0 Fibers form soft internal skeleton that supports other cell types, including white blood cells, mast cells, and macrophages.

0 Lymph nodes, bone marrow, and spleen.

Dense regular (dense c.t.)

0Attaches muscle to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction.

0Tendons, most ligaments, aponeuroses.

Elastic (dense c.t.)0 Allows recoil of tissue

following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration.

0 Dense regular connective tissue containing a high proportion of elastic fibers.

0 Walls of large arteries; within certain ligaments associated with the vertebral column; within walls of bronchial tubes.

Dense irregular (dense c.t.)0Able to withstand

tension exerted in many directions; provides structural strength.

0 Fibrous capusulesof organs and of joints; dermis of the skin; submucosa of digestive tract.

Hyaline (cartilage)0 Supports & reinforces; has

resilient cushioning properties; resists compressive stress.

0 Amorphous but firm matrix: collagen fibers form an imperceptible network; chondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae.

0 Forms most of embryonic skeleton; covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larnyx.

Elastic (cartilage)

0Maintains the shape of a structure while allowing great flexibility.

0 Supports the external ear; epiglottis.

fibrocartilage

0Tensile strength with the ability to absorb compressive shock.

0Matrix similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate.

0 Intervertebral discs; pubic symphysis; discs of knee joint.

Osseous tissue (bone)0Bone supports

and protects; provides levers for the muscle to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation

0Bones

Blood0Transport of

respiratory gases, nutrients, wastes, and other substances.

0 Contained within blood vessels.

Nervous tissue0Transmit electrical

signals from sensory receptors and to effectors (muscles and glands) which control their activity.

0Brain, spinal cord, and nerves.

Skeletal muscle0 Voluntary

movement; locomotion; manipulation of the environment; facial expression; voluntary control.

0 Long, cylindrical, multinucleate cells; obvious striations.

0 In skeletal muscles attached to bones or occasionally to skin.

Cardiac muscle

0 As it contracts, it propels blood into the circulation; involuntary control

0 The walls of the heart.

0 Branching, striated, generally uninucleatecells that interdigitateat specialized junctions (intercalated discs).

Smooth muscle

0 Propels substances or objects (food, urine, baby) along internal passageways; involuntary control

0 Mostly in the walls of hollow organs.

0 Spindle-shaped cells with central nuclei; no striations, cells arranged closely to form sheets.

Integumentary system:Meissner’s corpuscle:

0 they are light touch receptors in the skin, which are prone to touch sensitivity. They are hairless areas which have flattened cells and encapsulated nerve endings, such as fingertips, soles of feet, palms, eyelids, nipples, and the tip of the tongue.

Pacinian corpuscle:

0Deep pressure receptors;

0 a specialized bulblike nerve ending located in the subcutaneous tissue of the skin; occurs abundantly in the skin of palms and soles and joints and genitals

Blood vessel

0Blood vessels are intricate networks of hollow tubes that transport blood throughout the entire body.

Epidermis

0Avascular epidermis is a keratinized stratified squamosepithelium consisting of four distinct cell types and four or five distinct layers.

Stratum Corneum

0 Most superficial layer; 20-30 layers of dead cells represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space.

0 is the outermost layer of the epidermis, consisting of dead cells (corneocytes) that lack nuclei and organelles.

Stratum basale

0Deepest epidermal layer; one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers.

Dermis:[ papillary & reticular]

0 Papillary: the more superficial dermal region composed of areolar connective tissue. Very uneven and has fingerlike projection from its superior surface.

0 Reticular level: the deepest skin layer. It is compsed of dense irregular connective tissue and conains many arteries and veins, sweat and sebaceious glands, and pressure receptors (paciniancorpuscles)

Hair follicle:0 A structure formed from

both epidermal and dermal cells. Its inner epithelial root sheath, with two parts (internal/external), is enclosed by a thickened basement membrane, the glassy membrane, and connective tissue root sheath, which is essentially dermal tissue.

Hair shaft

0The portion of the hair projecting from the scalp surface.

Sweat glands/eccrine0 These exocrine glands are

widely distributed all over skin. Outlets for the glands are epithelial openings are called pores. Sweat glands are categorized by composition of their secretions:

0 Eccrine glands (merocrinesweat glands): produce clear perspiration consisting of water, salts, and urea. Important part of the body’s heat regulating apparatus.

Sebaceous glands0 Found nearly all over

skin except palms of hands and soles of the feet. Ducts usually empty into a hair follicle, but some open directly on the skin surface. Produces sebum (mixture of oily substances and fragmented cells that acts as a lubricant to keep skin soft and moist /keeps hair from becoming brittle). Tend to become oiler in duration of puberty.


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