Lecture 1: Epithelial cells and glands
The body consists of 4 (actually 5, but blood/lymph does not count now) basic tissue
types:
1 Epithelium
2. Connective tissue
3. Nerve tissue
4. Muscle tissue
These 4 basic tissue types are connected and form organ(systems)
Each tissue contains cells and a extracellular matrix
1.Epithelia ovecrview
Epithelium consists of a contiguous layer of cells, lining all external and internal lumens
(cavities). Anything that wants to enter from outside the body has to pass through the
epithelium. It contains a thin extracellular matrix (ECM).
Epithelia tissue functions:
- Covering tissue (e.g. skin)
- Transport along the surface of the epithelium (respiratory epithelium)
- Absorption (e.g. intestine)
- Secretion (e.g. glands)
, Intercellular adhesion and other junctions:
Tight junctions
-Promotes transcellular transport (transport of substances across an epithelium by
passing through the intercellular space between cells) and leads to decreased paracellular
transport (through cell)
-Secures polarity (apical (site of lumen) instead of basolateral (site of connective tissue))
Adherens junctions
-Anchor neighboring cells
Desmosomes
-‘Spot-welds’ or ‘snap buttons’ for firm cell-cell adhesion (connect epithelial cells)
Gap junctions
-Cell-cell communication
Hemidesmosomes
-Anchoring epithelial cells to the basement membrane !!
Papillae increase the area of contact between two tissues.
All epithelial cells are bordered by a basement membrane.
The basement membrane sublayers:
→ Basal lamina
-Epithelial cells
-Collagen fibers
→ Reticular lamine
- Secreted by connective tissue
- Reticular fibers
Functions of basement membrane (FAR)
-Filtration
-Attachment → laminin
-Regulating cell division and differentiation of epithelial cells (through binding of growth
factors)
The body consists of 4 (actually 5, but blood/lymph does not count now) basic tissue
types:
1 Epithelium
2. Connective tissue
3. Nerve tissue
4. Muscle tissue
These 4 basic tissue types are connected and form organ(systems)
Each tissue contains cells and a extracellular matrix
1.Epithelia ovecrview
Epithelium consists of a contiguous layer of cells, lining all external and internal lumens
(cavities). Anything that wants to enter from outside the body has to pass through the
epithelium. It contains a thin extracellular matrix (ECM).
Epithelia tissue functions:
- Covering tissue (e.g. skin)
- Transport along the surface of the epithelium (respiratory epithelium)
- Absorption (e.g. intestine)
- Secretion (e.g. glands)
, Intercellular adhesion and other junctions:
Tight junctions
-Promotes transcellular transport (transport of substances across an epithelium by
passing through the intercellular space between cells) and leads to decreased paracellular
transport (through cell)
-Secures polarity (apical (site of lumen) instead of basolateral (site of connective tissue))
Adherens junctions
-Anchor neighboring cells
Desmosomes
-‘Spot-welds’ or ‘snap buttons’ for firm cell-cell adhesion (connect epithelial cells)
Gap junctions
-Cell-cell communication
Hemidesmosomes
-Anchoring epithelial cells to the basement membrane !!
Papillae increase the area of contact between two tissues.
All epithelial cells are bordered by a basement membrane.
The basement membrane sublayers:
→ Basal lamina
-Epithelial cells
-Collagen fibers
→ Reticular lamine
- Secreted by connective tissue
- Reticular fibers
Functions of basement membrane (FAR)
-Filtration
-Attachment → laminin
-Regulating cell division and differentiation of epithelial cells (through binding of growth
factors)
