Classify simple epithelial cells on the basis of shape and position in the body.
1) Simple squamous-
- They are polygonal in shape.
- They are found lining areas where passive diffusion of gases occurs.
- Eg- skin, walls of capillaries, linings of the alveoli of the lungs etc.
(2) Simple cuboidal-
They are cuboidal in shape.
- They are secretory, absorptive or excretory in functions.
- Eg- small collecting ducts of kidney, pancreas, and salivary gland.
(3) Simple columnar-
They are long and elongated.
- They can cell can be secretory, absorptive, or excretory.
- They can be 1) Ciliated or 2) Non-ciliated.
- Ciliated columnar is found in fallopian tube and uterus.
- Non-ciliated epithelium also possesses microvilli.
(4) Pseudostratified columnar epithelium-
- They can be ciliated or non-ciliated.
- The ciliated type is also called respiratory epithelium as it is almost exclusively confined to the larger respiratory airways of the nasal cavity, trachea, and bronchi.