Epithelial Tissue - Histo Lec Flashcards
aggregates or groups of cells organized to perform one or more specific functions.
tissues
Four basic types of tissues:
– covers body surfaces, lines body cavities and forms glands
Epithelium
Four basic types of tissues:
underlies or supports the other three basic tissues, both structurally and functionally.
Connective
Four basic types of tissues:
made up of contractile cells and is responsible for movement
Muscle
Four basic types of tissues:
receives, transmits, and integrates information from outside and inside the body to control activities of the body.
Nerve
Avascular tissues
epithelial tissue
Covers body surfaces,
As receptors for the special senses
epithelial tissue
lines body cavities,
epithelial tissue
and constitutes glands;
epithelial tissue
Sheet of cells lying close together
epithelial tissue
Continuous sheet w/ little extracellular matrix
epithelial tissue
Function of Epithelial Tissue
a. Diffusion of O2 and CO2 across the epithelial cells of lung alveoli and capillaries
Transcellular Transport
Function of Epithelial Tissue
b. Carrier-protein mediated transport of amino acids
Transcellular Transport
Function of Epithelial Tissue
c. Vesicle-mediated transport of IgA and other molecules
Transcellular Transport
Function of Epithelial Tissue
Occurs via endocytosis and pinocytosis (columnar epithelium of the intestines and proximal convoluted tubules in the kidney)
Absorption
Function of Epithelial Tissue
Occurs via exocytosis (different glands produce perspiration, oil, digestive enzymes and mucus)
Secretion
Function of Epithelial Tissue
From abrasion and injury by the epithelial layer of the skin and gall bladder.
Protection
Function of Epithelial Tissue
Lining of Kidney tubules filtering wastes from blood plasma
Filtration
Structure of simple squamous
Single Layer of flattened cells
Function of simple squamous
Absorption, and filtration
Not effective protection – single layer of cells
Location of simple squamous
Walls of capillaries, air sacs in lungs
Form serous membranes in body cavity
Mesothelium (lining of peritoneum and pleura )
Endothelium (lining of blood vessels)
Structure of simple cuboidal
Single layer of cube shaped cells
Function of simple cuboidal
Secretion and transportation in glands, filtration in kidneys
Location of simple cuboidal
Glands and ducts (pancreas & salivary), kidney tubules, covers ovaries
Structure of simple columnar
Elongated layer of cells with nuclei at same level
Function of simple columnar
Absorption, Protection & Secretion
Special Features of simple columnar
Microvilli, finger-like projections of the apical surface, increase surface area for absorption
Goblet cells, single cell glands, produce protective mucus.
Location of simple columnar
Linings of entire digestive tract, gall bladder, uterus, kidney tubules
When open to body cavities, simple columnar are called ______
mucous membranes
Structure of pseudostratified
Irregularly shaped cells with nuclei at different levels – appear stratified, but aren’t.
All cells reach basement membrane
Function of pseudostratified
Absorption and Secretion
Features of pseudostratified
Goblet cells produce mucus
Cilia – hair-like projections; move fluid over cell surface or confer cell motility (larger than microvilli)
Location of pseudostratified
Respiratory Linings & Reproductive tract
Structure of stratified squamous
Several layer of cells with :
a. flattened cells (upper layer); b. polyhedral cells (middle layer) c. columnar cells (basal layer).
Types of stratified squamous
Stratified squamous non-keratinizing – flattened surface cells retain their nuclei; found in vagina, esophagus and tongue.
Stratified squamous keratinizing – flattened surface cells lose their nuclei, form a layer of dead keratinized cells; found in the skin
Also known as Urothelium
transitional epithelium
Location of transitional epithelium
Renal pelvis, urinary bladder, ureters & proximal 1/3 of urethra.