ch 4 tissue

 lines every body surface and all body cavities

Cellularity: almost entirely of cells bound by intercellular junctions;

Polarity:

•Apical surface is exposed may have ex microvilli

•Lateral surfaces have intercellular junctions

•Basal surface is attached to connective tissue underneath it

Avascularity: lack blood vessels;

Innervation: detect changes in environment

High regeneration capacity: surface is frequently damaged, quickly replaced

Physical protection:

Selective permeability:

Secretion:

Sensation:

-between epithelium and connective tissue

Composed of proteins and carbohydrates in discrete layers:

lamina lucida,

lamina densa,

reticular lamina

•Epithelial cells produce components of first two laminae

•Connective tissue cells produce reticular lamina

 intercellular junctions

•Tight junctions

•Adhering junctions

•Desmosomes

•Gap junctions

formed completely around the cell deep to the tight junction

 stabilize the apical surface of the epithelial cell

 locations of mechanical stress between cells

 thickened protein plaque on each of the apposed cell

connexon is a group of membrane proteins that forms a pore

Allow adjacent cells to communicate

•Polyhedral (“many-sided”) in a relaxed state

•Squamous when stretched

Simple Squamous Epithelium

-rapid exchange

-lun air sacs (alveoli)

Simple Cuboidal Epithelium

-absorption/secretion

-kidney tubules

Simple Columnar Epithelium

-absorption and secretion

ciliated

non ciliated

-most of digestive tract

Nonciliated

-uterine tube

may have microvilli (brush border) and goblet cells (secrete mucin)

Pseudostratified Columnar Epithelium(ciliated/ non ciliated)

- protection

-respiratory tract lining

Endocrine glands do not possess ducts; secrete hormones into interstitial fluid or bloodstream

2.Exocrine glands possess ducts

unicellular exocrine glands typically found in simple columnar and pseudostratified epithelia

Duct type -simple from compound glands

•Secretory portion - tubular, acinar or tubuloacinar

Gland secretion types -serous(watery), mucous(mucin), or mixed

Secretion methods-•

•Merocrine: secrete products from vesicles via exocytosis

•Apocrine: product stored in apical part of cell that pinches off

•Holocrine: cell accumulates product, then disintegrates

Physical protection

Support and structural framework

Binding of structures—

Storage—

Transport—

Immune protection—

Mesenchyme: the source of all adult connective tissue

Mucous connective tissue: found in umbilical cord

Resident cells: matain/repair extracellular matrix

fibroblasts- large, produce ground substances of extracellular matrix

adipocytes- single lipid droplet, store lipids

fixed macrophages- from monocytes in blood, phagocytize foreign material

mesenchymal cells- spindle shape stem cell, divide & response to injury

Wandering cells: repair extracellular matrix/immune

mast cells- filled cytoplasm, release histamine

plasma cells-from activated B-lymphocytes, form antibodies that bind to foreign substance, bacteria

free macrophages- mobile, phagocytize foreign material

other leukocytes-white blood cell, attack foreign materials (lymphocytes)

Collagen fibers: long, strong, unbranched- Most abundant protein

•Elastic fibers: thinner than collagen; stretch easily, branch, and rejoin

•Allow structures (for example, blood vessels) to stretch and recoil

•Reticular fibers: thinner than collagen fibers; form a branching, woven framework

•Found in the stroma of organs with abundant spaces such as liver, lymph nodes, and spleen

A combination of proteins and carbohydrates

Loose

Areolar CT

-protect

-papillary layer of dermis

Adipose Connective Tissue

Stores energy

subcutaneous fat

Reticular CT

supportive for lymphatic organs

stroma of spleen

Dense

Dense Regular CT

resist stress in 1 direction

Tendons

Dense irregular CT

Resists stress in all directions

- dermis

Elastic Connective Tissue

-stretching of some organs

-elastic arteries

chondrocytes cells

extracellular matrix called lacunae

perichondrium layer

Hyaline cartilage

movement of joint

-articular cartilage of long bones

Fibrocartilage

Absorbs shock

- intervertebral discs

Elastic cartilage

Extremely resilient and flexible-Extremely resilient and flexible

Periosteum: Dense irregular connective tissue covering

Mature bone cells are called osteocytes

compact bone

cylindrical osteons, each containing concentric lamellae surrounding a central canal

•Osteocytes contact one another through canaliculiSpaces within spongy bone house hemopoietic cells that generate blood cells

spongy bone

Blood

•Plasma: a watery ground substance containing protein fibers-clots

•Erythrocytes: red blood cells -transport oxygen

•Leukocytes: white blood cells-immune

•Platelets: fragments of blood cells-clots

-blood vessel

Lymph is derived from plasma

•Mucous membranes line passages that open to external environment

•Serous membranes (for example, pericardium) have two layers (parietal and visceral) and secrete friction-reducing fluid between them

•Cutaneous membrane is the skin (epidermis and dermis)

•Synovial membranes line the cavities of some joints and secrete friction-reducing fluid there

Skeletal muscle tissue

-Moves body

-Attaches to bone and/or skin

Cardiac muscle tissue

-Autorhythmic-initiate own contraction

-wall of the heart (myocardium)

Smooth muscle tissue

•Not striated

- involuntary movement

-stomach

Neurons: nerve cells capable of initiating and conducting electrical activity throughout the body

•cell body, branches of dendrites that receive signals, and a long axon that carries signals toward other cells

•Glial cells: cells that support and protect neurons

-Communication and control of body functions

-brain, spinal cord

•Metaplasia: epithelia lining respiratory airways of people who smoke change from pseudostratified ciliated to stratified squamous

•Hypertrophy: an increase in the size of existing cells

•Hyperplasia: an increase in number of cells in a tissue

•Neoplasia: out-of-control growth, which forms a tumor

•Atrophy: shrinkage of tissue by cell size or number

Stratified Squamous Epithelium Apical cells are squamous and deeper layers cuboidal or polyhedral

-protection

Keratinized-epidermis of the skinNonkeratinized-lining of vagina

Stratified Cuboidal Epithelium

-Protection, secretion

- lining of sweat gland duct

Stratified Columnar Epithelium

-Protection, support, and secretion

male urethra

Transitional Epithelium Multiple layers, apical cell shape varies depending on degree of stretch-Some binucleated cells

-accommodate urine volume

-lining of urinary tract

histamine

hemopoietic

simple squamous epithelium that lines lumen of blood and lymphatic vessel and heart

simple squamous epithelium of serous membrane

acini