tissue level of organization

what is tissue

a group of closely associated cells that perform related functions and are similar in structure

what are the four types of tissue

epithelial tissue (covering), connective tissue (support), muscle tissue (movement), nervous tissue (control)

what is extra cellular matrix

proteins (cells and fibers), ground bustances (jelly like substances)

where can you find epithelial tissue

covers a body surface or lines a body cavity; forms most glands

what are the functions of epithelium

protection, absorption, secretion, ion transport, filtration, forms slippery surface

what are characteristics of epithelial tissue

cellularity, specialized contacts, polarity, avascular by inverted, regeneration

what is epithelial cellularity

cells separated by minimal extracellular material

what are the specialized contacts of epithelial

cells joined by special junctions

what is epithelial polarity

cell regions of the apical surface differ from the basal surface

what is avascular by inverted

epithelial receive nutrients from underlying connective tissue

what is regeneration

lost cells are quickly replaced by cell division

what are some types of cell junctions

desmosomes, tight junctions, gap junctions

what are desmosomes

an anchoring junction

what are tight junctions

prevent molecules from passing through intercellular space

what are gap junctions

allows small molecules to move directly between neighboring cells

what are cilia

whiplike, highly motile extensions of apical surface membrane

what are microvilli

finger like extensions of plasma membrane

how do you classify epithelial tissue

first name (indicate # of cell layers) last names (describes shape of cell)

what are the first names of epithelial tissue

simple (one layer) stratified (more than one layer)

what are the last names of epithelial tissue

squamous (plate like), cuboidal (cube like), columnar (column like)

what are simple epithelial

single layer of cells; important for passive diffusion (squamous) or absorption/secretion (cuboidal/columnar)

what are the special cases of simple epithelial

endothelium and pseudostratified columnar

where is endothelium found

in the hollow organs of the circulatory system (heart and vessels)

what do pseudostratified columnar always touch

all cells touch the basement membrane

what are stratified epithelial

more durable, major role is protection, regenerates from below, exfoliates

how are surface cells replaced

basal cells divide and push apically

what is keratinized stratified epithelial

waterproofed by dead layer of cells (dry)

what is nonkeratinized stratified epithelial

esophagus, vagina; no dead layer of cells with keratin (forms moist lining of body cavities)

what are stratified squamous epithelium

many layers of cells are squamous in shape, deeper layers of cells appear cuboidal or columnar;

what is the thickest epithelial tissue

stratified squamous epithelium

what are stratified squamous epithelium adapted for

protection from abrasion

where is transitional epithelium found

lines the inside of hollow urinary organs (bladder) and umbilical cord

why is transitional epithelium transitional

the bladder fills, it stretches and thins the six cell layer to three and the apical cells flatten from a round shape to a squamous shape

what do glands do

secrete water-based fluids that usually contain proteins

what is secretion

process whereby gland cells obtain needed substances from the blood and transform them chemically into a product that is then discharged from the cell

what are endocrine glands

ductless glands, that secrete directly into surrounding tissue fluid-fa; produces messenger molecules called hormones

what are exocrine glands

ducts carry products of exocrine glands to epithelial surface

what are the diverse glands of the exocrine glands

mucus-secreting, sweat and oil glands, salivary glands, liver and pancreas

what are unicellular exocrine glands

goblet cells that produce mucin

what do mucin a water create

mucus

what does mucus do

protects and lubricates many internal body surfaces

what are the shapes of secretory cells

tubular (uniform diameter), acinar/alveolar (dilated sac), tubuloacinar (a gland in which the acini and tubules secrete)

what is the most diverse and abundant tissue

connective tissue

what are the main classes of connective tissue

connective tissue proper (fibrous), cartilage (support), bone tissue (support), blood (fluid)

what are the important functions of connective tissue

form basis of the skeleton, store & carry nutrients, surround blood vessels & nerves, lead fight against infection, physical protection

what are special characteristics of connective tissues

few cells, abundant extracellular matrix

what is extracellular matrix composed of

ground substance and fibers; produces by cells of the connective tissue

what are the cells of connective tissues

fibroblasts (fibers), osteocytes (bone), chondrocyte(cartilage), leukocytes (wbc), erythrocytes(rbc), adipocyte (fat)

what are the of fibers of connective tissue

collagenous fibers, reticular fibers, elastic fibers

what are collagenous fibers

white fibers, tendons, ligaments, dermis, tough and flexible

what are reticular fibers

collagen fibers coated with glycoprotein; forms sponge like framework (spleen and lymph nodes)

what are elastic fibers

allows stretching and recoiling; lungs, skin, arteries

what is ground substance

produced by primary cell type of the tissue, usually gel-like/rubbery substance,

what do ground substance dos

cushions and protects body structures, hold tissue fluid (protein and carbohydrate mixture); blood is an exception

what are loose connective tissues

areolar, adipose, and reticular

what are dense connective tissue

irregular and regular

what is areolar connective tissue

supports and binding of tissues, holds body fluid, defends body against infections, stores nutrients as fat, waste removal

what is adipose tissue

stores nutrients, highly vascularized, mostly found in hypodermis

where is adipose tissue mostly found

around heart, lymph nodes, eye, some muscles

what is reticular connective tissue

resembles areolar tissue but only has reticular fibers in extracellular matrix

where is reticular connective tissue found

important stroma for spleen, lymph nodes, thymus, and bone marrow

what is dense irregular connective tissue

similar to areolar connective tissue but collagen fibers much thicker; two layers running perpendicular

what is dense regular connective tissue

fibers run the same direction, parallel to the direction of pull; poorly vascularized and no fat or defense tissue

where is dense regular connective tissue found

ligaments, tendons, aponeuroses fascia around muscles

what is blood connective tissue

formed elements, erythrocytes (rbc), leukocytes (wbc), thrombocytes (platelets)

what is formed elements

cells or pieces of cells surrounded by a nonliving matrix (plasma)

what are leukocytes

neutrophils, eosinophils, basophils, monocytes, lymphocytes (t and b cells)

what is cartilage

resist compression and tension; firm but flexible, cells separated by abundant extracellular matrix; no blood vessels or nerves

how much water does cartilage hold

80% water

what is within bone connective tissue

contains inorganic calcium salts and collagen fibers

what is in the haversian system

central canal, lacunae, lamellae, canaliculi, osteocytes, periosteum, osteoblasts, osteoclasts

what are muscle fibers

elongated shape and contract (myofilaments-actin and myosin)

what are skeletal muscle

striated, multinucleated, and cause body
movements because they pull on bones

what are cardiac muscle

striated, mononucleated, cells are
connected at special junctions called intercalated
discs (allows syncopated contraction of heart)

what are smooth muscle

no striations, spindle shaped,
mononucleated and in walls of hollow viscera
(involuntary muscle)

what are neural tissue

brain, spinal cord, nerves, neurons, supporting cells

what are neurons

conduct electrical impulses; soma, dendrites, axon

what are supporting cells in neural tissues

noursih, insulate, and protect (neuroglia)