an orientation to the tissues of the body (4-1 The for tissue types are…
an orientation to the tissues of the body
4-1 The for tissue types are
This tissue covers body surfaces, lines cavities and tubular structures and serves essential functions
includes epitheila and glands
these layers cover internial and externial surfaces such as the digestive respiorty reproductive and urinairy tracts
Cells that secrete and regulate are extracellular material and fluids combine to form TISSUES with special functions combine to form ORGANS with multiple functions interact ORGAN SYSTEMS
EPITHELIA 1. cover exposed surfaces 2. line internal passageways and chambers 3. produce glandular secreations
CONNECTIVE TISSUES 1. fill internal spaces 2. provide structural support 3. store enegry
MUSCLE TISSUE 1. contracts to produce active movement
NEURAL TISSUE 1. conducts electrical impulses 2. carries information
Histology is the study of tissues
200 types of cells that combine to form tissue
Epithelia's important characteristics are above
cells that are bound closley together and other tissue types. the cells are widely seperated by extracellular materials
A free (apical) surface exposed to the enviornment or to some internal chamber or passageway
attachment to the underlying connective tissue by basement membrane
the absence of blood vessles, because of this avasuclar condition epitheal cells must obtain nutrients across thier attached surface from deeper tissues across their exposed surfaces
continual replacement or regeneration of epithelial cells are damaged or lost at the exposed surface
1.provide physical protection 2. control permeability 3. provide sensation 4. produce specialized secretions
Exocrine : secretions are discharged onto the surface of the epithelium. enzymes entering the digestive tract, perspiratatoin on the skin, and milk produced by mammary glands
Endocrine: secretions are released into the surrounding tissue fluid and blood. these secretions called hormones, act as chemical messengers and regulate or coordinate the activites of other tissues,organs, and the pancreas, thyriod, and pituitary gland
INTERCELLULAR CONNECTIONS - to be effective in protecting other tissues, epitheial cells must remain firmly attached to the basement membrane and to eachother to complete a cover or lining
(CAMs) - Cell Adhesion Molecules
Cell shapes of epithelial tissue? 1. columnar, 2, cuboidal,3. squamous cell shapes.
Classifying Epithelia 1. Simple : is found in protected regions where absorpition takes place or where a slippery surface reduces friction one layer
Simple epithelial tissues are generally classified by the shape of their cells. The four major classes of simple epithelium are: 1) simple squamous; 2) simple cuboidal; 3) simple columnar; and 4) pseudostratified.
Locations : Simple squamous epithelia are found in capillaries, alveoli, glomeruli, and other tissues where rapid diffusion is required. Cells are flat with flattened and oblong nuclei. ... This epithelium is associated with filtration and diffusion.This tissue is extremely thin, and forms a delicate lining.
Functions: Reduces frictions, controls vessels and preforms absortion and secretion
Simple cuboidal epithelia are found on the surface of ovaries, the lining of nephrons, the walls of the renal tubules, and parts of the eye and thyroid. On these surfaces, the cells perform secretion and absorption.
Functions: Limited protection , secretion, absoration
A simple columnar epithelium is a columnar epithelium that is uni-layered. In humans, a simple columnar epithelium lines most organs of the digestive tract including the stomach, small intestine, and large intestine. Simple columnar epithelia line the uterus.
Functions: protection, secretion, absortion
Location of Stratified epitheluim: nonkeratinized type forms the moist lining of the esophagus, mouth, and vagina; keratinized type forms the epidermis of the skin, a dry membrane.
Stratified squamous epithelium is a type of tissue found covering and lining parts of the body. In this tissue, cells are flattened, joined tightly together, and stacked. The major function of this tissue type is protection, as it is found in areas that undergo wear-and-tear.
Stratified columnar epithelia are found in the conjunctiva of the eye, in parts of the pharynx, anus, the uterus, and the male urethra and vas deferens. It is also found in the lobar ducts in salivary glands
Stratified columnar epithelium is a rare type of epithelial tissue composed of column shaped cells arranged in multiple layers. Stratified columnar epithelia are found in the conjunctiva of the eye, in parts of the pharynx, anus, the uterus, and the male urethra and vas deferens.
Transitional epithelium is a layer of cells that forms the mucosal lining of your ureters, a portion of your urethra, and your urinary bladder.
Function. The transitional epithelium cells stretch readily in order to accommodate fluctuation of volume of the liquid in an organ. (The distal part of the urethra becomes non-keratinized stratified squamous epithelium in females; the part that lines the bottom of the tissue is called the basement membrane.)
mechanism of secretion In contrast, excretion, is the removal of certain substances or waste products from a cell or organism. The classical mechanism of cell secretion is via secretory portals at the cell plasma membrane called porosomes.
Serous glands: cells secrete a watery fluid, ... In merocrine glands, the glandular cells remain intact and the products of their synthetic activity are secreted in vesicles via exocytosis. Serous gland cells use this mode of secretion, such as those in the pancreas. This is the most common mechanism of secretion.
Merocrine : Serous glands: cells secrete a watery fluid, ... In merocrine glands, the glandular cells remain intact and the products of their synthetic activity are secreted in vesicles via exocytosis. Serous gland cells use this mode of secretion, such as those in the pancreas. This is the most common mechanism of secretion.
Apocrine: Apocrine secretion is less damaging to the gland than holocrine secretion (which destroys a cell) but more damaging than merocrine secretion (exocytosis). An example of true apocrine glands is the mammary glands, responsible for secreting breast milk.
Holocrine: Holocrine is a term used to classify the mode of secretion in exocrine glands in the study of histology. Holocrine secretions are produced in the cytoplasm of the cell and released by the rupture of the plasma membrane, which destroys the cell and results in the secretion of the product into the lumen.
Tight Junction: a specialized connection of two adjacent animal cell membranes such that the space usually lying between them is absent.
intercellular junctions are structures which provide adhesion and communication between cells. They are mostly present in epithelial cells that are especially characterized by their strong attachment one to another and to extracellular matrix.
Gap junctions are a specialized intercellular connection between a multitude of animal cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.
a structure by which two adjacent cells are attached, formed from protein plaques in the cell membranes linked by filaments.