A simple epithelium has cells that form a single layer that are attached to the basement membrane. A stratified epithelium, on the other hand, consists of multiple layers of cells where only the basal layers are attached to the basement membrane.Know More
The epithelium is one of the four major tissues in the body. It is made up of cells that are usually arranged in sheets or tubules that are connected to the underlying basement membrane. The epithelium serves as a covering for a number of internal and external surfaces of the body, and it can form glandular structures.
Different types of epithelia are classified according to the shape of the cells and whether or not the cells are layered. A simple epithelium may also appear as stratified and this type is classified as "pseudostratified epithelium." The cells that make up the epithelium are classified according to shape. These classifications are squamous (flat), cuboidal and columnar.Learn more about Biology
Goblet cells can be found in the epithelium of the small and large intestines. These cells secrete mucus to make food pass more easily through the digestive tract.Full Answer >
The fluid mosaic is a model created in 1972 by S.J. Singer and Garth Nicolson to portray the structure of a plasma membrane. The model helps to understand the structure and function of a membrane, which in its composition includes proteins, phospholipids, carbohydrates and cholesterol.Full Answer >
Osmosis is a particular type of diffusion in which water crosses a semi-permeable membrane to an area with a greater solute concentration, whereas standard diffusion often allows the free movement of both solutes and solvent toward equilibrium. Diffusion in general is the net movement of molecules in solution from areas of higher concentration to areas of lower concentration. Osmotic pressure is potentially very powerful, with osmotic pressure being the only force necessary to move water from the roots to the tops of the tallest trees in the world.Full Answer >
The Gibbs-Donnan equilibrium refers to the behavior that charged particles exhibit when they are near a semipermeable membrane. Specifically, it explains how the electrostatic and osmotic forces balance out to restore equilibrium. To help with these relationships, the Gibbs-Donnan equilibrium assigns factors to different molecules. These values vary depending on whether they are assigned to a negatively charged anion or positive cation. The values are slightly higher for the anions.Full Answer >