Human Anatomy and Physiology Tissues

epithelial tissue

tissue: cells are avascular (closely packed together, little or no intercellular material between adjacent cells); major roles include secretion, absorption, protection, and synthesizing hormones; covers external body surfaces and lines inner walls of cavities and organs; has basement membrane (attachment) and free surface (exposed side); classified by shape and layer

squamous

epithelium: flat

cuboidal

epithelium: cube-shaped

columnar

epithelium: greater in height than width

simple

epithelium: single layer

stratified

epithelium: multiple layers

simple squamous

epithelium: singer layer of flat cells; lines inside wall of blood vessels, forms walls of capillaries and lung air sacs - absorption by diffusion, filtration, osmosis; secretion

simple cuboidal

epithelium: single layer of cube-shaped cells; forms walls of ducts in skin glands and kidney tubules - secretion, absorption

simple columnar

epithelium: single layer of column-shaped cells; lines inside walls of stomach and intestines - protection, secretion, absorption, moving of mucus w/ cilia

stratified squamous

epithelium: multiple layers of cells, with cells along free edge flattened in shape; superficial layer of the skin, mouth, and throat (friction) - protection

pseudostratified columnar

epithelium: single layer of irregularly shaped cells that appear multi-layered, often with cilia; lines inside walls of larynx, trachea, and bronchi - protection

transitional

epithelium: multiple layers of spherical or irregularly shaped cells; lines inside walls of urinary bladder and ureter - permits stretching

glandular

epithelium: specialized epithelium that manufacture and secrete products

exocrine glands

glands that empty products into ducts. the ducts transport products to the body surface or into a cavity. (salivary glands, oil glands in skin, sweat glands)

endocrine glands

glands that secrete products into the extracellular space, where the products diffuse into the bloodstream. (pituitary gland, thyroid gland, adrenal glands)

connective tissue

tissue: cells are vascular (widely scattered with large amounts of nonliving intercellular material); contains ground substance (protein-sugar molecules and protein fibers); functions include supporting body structures and gluing tissues and organs in place; contains two types of cells: one maintains intercellular material and one protects tissue from infections; has great capacity for growth and repair

collagenous fibers

type of protein fiber in connective tissue; thick, wavelike strands; resists stretching; has great tensile strength; composed of most abundant protein in the body (found in tendons, scar tissue)

elastic fibers

type of protein fiber in connective tissue; elasticity (ability to stretch) and extensibility (ability to return to original shape); found in skin

reticular fibers

type of protein fiber in connective tissue; resists physical stress; least abundant of all the fibers

areolar tissue

loose connective tissue; most common connective tissue; all 3 protein fibers present in a fluid ground substance; has fibroblasts (cells that produce fibers and ground substance) and macrophages (white blood cells); functions include being a structural anchor to body parts; found between skin and muscles, surface of organs, filling spaces between organs

adipose tissue

loose connective tissue; has adipocytes (specialized fibroblasts that contain large deposits of fat); has minimal intercellular material; functions include storing energy as fat, being an insulating pad between organs, being a shock absorber

reticular tissue

loose connective tissue; contains reticular fibers; makes a 3D network for support in the liver and spleen

dense connective tissue

connective tissue: protein fibers are packed closely together with little ground substance

dense irregular connective tissue

connective tissue: fibers extend in various directions; found in skin and round bone and cartilage

dense regular connective tissue

connective tissue: fibers extend parallel to each other; found in tendons and ligaments

cartilage

connective tissue: more solid than connective tissue proper; has a matrix of protein fibers and thickened ground substance; has chondrocytes (cartilage cells that maintain the matrix, embedded in small chambers called lacunae); has perichondium (dense connective tissue that surrounds the cartilage and is vascular; materials diffuse from perichondrium to chondrocytes); 3 types

hyaline cartilage

connective tissue: most abundant type of cartilage; matrix is dominated by chondroitin sulfate and collagen; sparsely distributed chondrocytes in matrix; found in the upper portion of the respiratory tract (trachea and bronci), ends of bones and ribs, skeleton of a fetus

elastic cartilage

connective tissue: elastic fibers dominate the matrix and weave through the chondrocytes; found in ears, end of nose, epiglottis

fibrocartilage

connective tissue: solid, flexible matrix containing primarily collagen fibers; collagen fibers are dark, wavy lines that weave around the chondrocytes; found in joints and intervertebral discs

bone

connective tissue: matrix (intercellular material) is filled with mineral salts and collagen fibers; durable and hard; has osteocytes (secrete bone matrix, embedded in chambers called lacunae); 2 types

compact bone

connective tissue: composed of osteons or haversian systems; osteons form concentric circles throughout it; has osteonic canal or haversian canal (extends through middle of osteon, contains blood vessels)

blood

connective tissue: has living cells; plasma is the fluid matrix that contains fibers that come into action during clotting; transports gases, nutrients, wastes, etc.

muscle tissue

tissue: highly specialized to contract in order to produce movement of some body parts

skeletal muscle

muscle tissue: long, threadlike, alternating light/dark cross markings called striations, many nuclei, can stimulate a muscle cell to contract, found in muscles that attach to bones, controls voluntary movements

cardiac muscle

muscle tissue: alternating light/dark cross markings called striations, branched, joined end to end, intricate networks, single nucleus, intercalated disc where cells touch, cannot stimulate a muscle cell to contract, found in heart, controls involuntary movements

smooth muscle

muscle tissue: no striations, short, spindle-shaped cells, single/central nucleus, cannot stimulate a muscle cell to contract, found in walls of hollow internal organs, controls involuntary movements

nerve tissue

tissue: composed of two major cell populations

neuroglial cells

nerve tissue: special supporting cells that protect, support, and insulate the neurons

neurons

nerve tissue: branching cells that have cell processes (axons and dendrites) that may be quite long and extend from the nucleus-containing body

body membranes

cover surfaces, line body cavities, and form protective sheets around organs

cutaneous membrane

body membrane: skin; superficial epidermis is composed of a stratified squamous keratinizing epithelium while underlying dermis is dense, fibrous connective tissue; exposed to air and is a dry membrane

mucous membrane

body membrane: lines all body cavities that open to the exterior; composed of various epithelial tissue (mostly stratified squamous or simple columnar) resting on loose connective tissue; wet or moist membrane continuously bathed in secretions

serous membrane

body membrane: lines body cavities that are closed to the exterior; composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue; membranes work in pairs parietal and visceral (next to the organ) and secrete serous fluid in between the two layers; organs can slide easily across the cavity walls and each other with a minimum of friction

synovial membrane

body membrane: lines joints and small sacs of connective tissue called bursea and tendon sheaths in order to cushion and lubricate during activity; composed of connective tissue only

characteristics of cancer

1 hyperplasia- uncontrolled cell division (cells activate telomerase - continually rebuilds chromosomes so that cells are not signaled to stop dividing)

2 dedifferentiation- cells lose many of the specialized structures/functions

3 invasiveness- cells break through boundaries (basement membranes) that separate cell layers within some organs

4 angiogenesis- cells induce extension of blood vessels (nourish cells and remove wastes

5 metastasis- cells spread (metastasize) to other tissues; cand etach from their original mass and move from their place of origin, into bloodstream or lymphatic system

benign

noncancerous (could be a cyst- solid fibrous mass of connective tissue called fibroadenoma)

malignant

cancerous

keratinized

epithelium: thick sheet of dead cells with no visible nuclei along free surface of tissue

nonkeratinized

epithelium: cells with visible nuclei along free surface of tissue