Anatomy Exam 1 Chapter 4

two basic components of all tissues

cells and extracellular matrix

high cellularity

high cells, low extracellular matrix

four main tissue types and their principal functions

epithelial tissue - covering, form lining of internal structures and glands

connective tissue - support

muscle tissue- movement, heat production

nervous tissue- control, communication

epithelial tissue general characteristics

-cells arranged in continuous sheets (single or multiple layers)

-cells closely packed and held tightly together (high cellularity)

-found at a boundary between two different environments (interface)

two general types of epithelium

1-covering and lining epithelium

>covers outer surfaces, lines inner surfaces

2-glandular epithelium

>forms most glands of the body

>sweat, oil, milk, pituitary

epithelium general functions

protection of underlying tissues, barriers, regulate things

secretion

absorption

diffusion

filtration

sensory reception

special features of epithelia

high cellularity

specialized contacts: proteins used to hold cells together (bc a lot)

polarity: apical(free), basal

support by connective tissue

avascular: no direct blood supply, no capillaries

nervous innervation: usually vessels and nerves are together, but not here

regeneration: healing, lives at dangerous, innerface locations prone to damage

basement membrane

has 2 layers: the basal lamina (secreted by epithelium) and reticular lamina (part of the underlying connective tissue)

classifications of epithelial

simple: one layer of cells

stratified: several layers of cells

squamos: flat, thinnest in body

cuboidal: same size all around

columnar: taller than they are wide

some might have cilia and be ciliated

simple squamos epithelium

single layer of flattened cells, disc-shaped nuclei, sparse cytoplasm

function: diffusion and filtration of materials

location: kidneys, air sacs of lungs, lining of heart, blood vessels, lymphatic vessels, lining of ventral body cavity

when SSE forms a serous membrane, it is mesothelium

simple cuboidal epithelium

single layer of cubelike cells, large spherical nuclei

function: secretion and absorption

location: kidney tubules, ducts and secretory portions of small glands, ovary surface

tightly packed rings

simple columnar epithelium

single layer of tall cells, round to oval nuclei, may contain goblet cells (mucus secreting), may have cilia

function: absorption, secretion of mucus and enzymes, ciliated type propels mucus

location: nonciliated type lines digestive tract (stomach to anus), gallbladder, and excretory ducts of some glands; ciliated type lines small bronchi, uterine tubes, and some areas of uterus

pseudostratified columnar epithelium

single layer of cells of differing heights, some not reaching free surface; may have goblet cells and cilia

function: secretion of mucus, propulsion of mucus

location: nonciliated type in sperm carrying ducts and ducts of large glands, ciliated type lines trachea and most of upper respiratory tract

type of simple columnar with more

all cells touch basement membrane

stratified squamos epithelium

thick membrane composed of several cell layers; basal cells are cuboidal or columnar; surface cells are squamos; in keratinized type, surface cells are full of keratin and dead; basal cells produce cells of more superficial layers

function: protects underlying tissues in areas subjected to abrasion

location: nonkeratinized type forms moist linings of esophagus, mouth, vagine; keratinized type forms epidermis of skin, a dry membrane

name based on shape at apical surface

stratified cuboidal epithelium

generally two layers of cubelike cells

function: protection

location: largest ducts of sweat glands, mammary glands, and salivary glands

makes a ring and it’s two layers

stratified columnar epithelium

several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar

function: protection, secretion

location: rare in body, small amounts in male urethra and in large ducts of some glands

tight junctions

seal cells together to form a fluid barrier, prevents molecules from passing through intercellular space

prevent paracellular transport (b/w cell)

desmosomes (anchoring junctions)

hold cells together that are under mechanical stressors

bind adjacent cells together and help form an internal tension-reducing network of fibers

like teeth on a zipper interlock

gap junctions

communicating junctions allow ions and small molecules to pass from one cell to the next for intercellular communication

tubular components of cells fuse together

basal lamina

part of the basement membrane, but sometimes these labels are interchangeably

free space and nuclei

apical surface features of epithelium

microvilli ( non-motile and function to increase surface area at apical area) and cilia (function to move things along the surface of a cell)

actin filaments make up microvilli; PM covers entire outside of actin microfilament

microtubules make up individual cilia

glands

epithelia that make and secrete a product form glands

secretions are aqueous fluids that usually contain proteins

-hormones

-mucous

-sweat and oils

-bild and digestive enzymes

-milk

endocrine glands

secretions=hormones

hormones are released directly into ECF and then diffuse into blood stream w/o a duct

effector organs are far away

exocrine glands

secretions flow onto body surfaces or into cavities

secretions act locally, effector organ is nearby

multicellular: multiple cells form a gland that secretes product via a duct

unicellular: one-celled gland