Anatomy I - Epithelial Tissue and Integument Flashcards
Epithelial Tissue and Integument
Hierarchy of Body Structure (Organization of Animals)
- Cells – smallest functional, living (basic) units
- Tissues – structurally similar cells; their product(s) grouped together to perform a common function
- Organ – specialized structure consisting of two or more different tissues
- Organ System – an aggregate consisting of at least two organs for a common functional purpose
- Organism – the summation of the organ systems
Composition (Components) of All Tissues
- Cells
- Cell Products = Intercellular Substance – all the ‘stuff’ between the cells
a. Fibers – formed elements… threadlike
b. Ground Substance – amorphous… background material
Four Basic Tissues of the Human Body
- Epithelial Tissue
- Connective Tissue
- Muscle Tissue
- Nervous Tissue
Membrane Epithelium Characteristics
a. Highly cellular with very little intercellular substance
b. Free surface faces (exposed to) air or fluid (inside of air passages, GI tract, blood vessels, etc.)
c. Basal surface is attached to a basement membrane, which separates it from the vascular
connective tissue layer deep to it
d. Avascular – dependent upon diffusion for survival
e. Surface cells often have specializations
Membrane Epithelium Functions
a. Protection – from mechanical trauma, abrasion, desiccation, bacteria
b. Transport – of fluids through (or “across”) the membrane
c. Secretion – releasing glandular products
d. Absorption – taking of materials into the cell
e. Excretion/Lubrication – releasing cell wastes… sweat(ing), oil, etc.
Number of cell layers
1) Simple – one layer of cells
2) Stratified – more than one layer of cells
Cell shape
1) Squamous – flat cell
2) Cuboidal – cell are about as tall as they are wide – not truly cuboidal when seen three
dimensionally
3) Columnar – taller than they are wide
Simple Squamous Epithelium Locations
a. Endothelium – lining of blood vessels
b. Bowman’s capsule – kidney
c. Thin segments of the loop of Henle – kidney
d. Alveoli of lungs
Simple Squamous Epithelium Functions
a. Transport
b. Diffusion
Simple Cuboidal Epithelium Locations
a. Lining of several of the tubules of the kidney
b. Ovary
c. Lining of many ducts of glands
Simple Cuboidal Epithelium Functions
a. Secretion
b. Transport
c. Absorption
Simple Columnar Epithelium Locations
a. Lining of GI tract
b. Lining of uterus
c. Lining of oviduct
Simple Columnar Epithelium Functions
a. Protection
b. Lubrication
c. Absorption
d. Secretion
Pseudostratified (ciliated) Columnar Epithelium
appears stratified when looking at a histological section though
this is false; every cell is attached to the basement membrane but not all cells have a free surface
Pseudostratified (ciliated) Columnar Epithelium Locations
respiratory tract
Pseudostratified (ciliated) Columnar Epithelium Functions
a. Protection
b. Secretion
Stratified Squamous Epithelium
several layers of cells with the cells of the free surface being flattened
Keratinized stratified squamous epithelium
the surface cells are dead cells filled with keratin
Dry
Keratinized stratified squamous epithelium Locations
1) Skin
2) Gingiva
3) Hard palate
Keratinized stratified squamous epithelium Functions
mainly protection from abrasion, desiccation, UV light
Non-keratinized stratified squamous epithelium
Moist
Non-keratinized stratified squamous epithelium Locations
1) Mouth
2) Esophagus
3) Vagina