Question | Answer |
What are the common characteristics of Epithelial Tissue? | 1. Celularity - little ground substance, cells bound by cell junctions
2. Polarity - apical/basal surface
3. Attachment -- basement membrane
4. Avascularity --> nutrients obtained by diffusion or absorption.
5. Regeneration --> mitosis of stem cells |
What are the common functions of Epithelial tissue? | 1. physical protection
2. "gatekeepers" control permeability
3. Provide sensation --> large nerve supply
4. Produce specialized secretions (gland cells) |
What is the basement membrane of an Epithelial cell and what is it composed of? | Composition = 1. basal lamina: collagen fibers, protein and carbohydrates secreted by the basal surface of the epithelial cell. 2. reticular lamina = protein fibers and carbohydrates secretes by the connective tissue cells. |
What is the function of the basement membrane of an epithelial tissue? | 1. physical support, anchored to the conective tissue.
2. barrier - regulate movement of large molecules between epithelium and connective tissue. |
What is a tight junction and its function? | adjacent cell membranes are tightly bound at apical surface by interlocking membrane protiens (at lipid portions of membrane)
Prevent passage of H2O and solutes between cells. |
What is a desmosome and its function? | CAM's and proteoglycons (protein fibers) link the opposing cell membranes--connected to cytoskeloton = really strong.
hemidesmosomes = 1/2 desmosome that anchor cell to basal lamina |
What is a Gap Junction and its function? | two cells held together by a link of connexons (carrier proteins)
allows a passage or pore to allow solutes and other nutrients to pass from cell to cell. |
Simple Squamous Epithelium
(structure, function, location) | * this, flat, somewhat irregular --delicate
* easy diffusion, osmois, or absorption/secretion
* located in protected regions where diffusion/absorption takes place, alveoli, lining of ventral cavties, lining of heart and blood vessels. |
Mesothelium: define | Simple squamous epithelium that specifically lines the ventral body cavities:
pleura, peritoneum, and pericardium |
Endothelium: define | simple squamous epithelium that specifically lines the inner surface of the heart and all the blood vessels. the lacunae of the vessels. |
Simple Cuboidal Epithelium
(Structure, function, location) | * tall as wide, "hexagonal boxes"; distance between nuclei = height of cell.
* limited protection, BUT good for secretion and absorption |