Plants protect themselves by releasing hydrogen peroxide to fight against fungal invasion. Another way is by secreting c.. Find out more about New Zealand's unique biodiversity by exploring a range of different ecosystems and the key role of s.. This tutorial looks at the mutation at the gene level and the harm it may bring.
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There are over.. Secretes and protects Transitional epithelium. Lines the bladder, urethra and ureters Allows the urinary organs to expand and stretch Types of Epithelial Tissue Epithelial tissue is classified by cell shape and the number of cell layers. Most epithelial tissue is described with two names. The first name describes the number of cell layers present and the second describes the shape of the cells.
For example, simple squamous epithelial tissue describes a single layer of cells that are flat and scale-like in shape.
Epithelial Tissue : There are three principal classifications associated with epithelial cells. Squamous epithelium has cells that are wider than they are tall. Cuboidal epithelium has cells whose height and width are approximately the same.
Columnar epithelium has cells taller than they are wide. Simple epithelium consists of a single layer of cells. They are typically where absorption, secretion and filtration occur.
The thinness of the epithelial barrier facilitates these processes. Simple epithelial tissues are generally classified by the shape of their cells. The four major classes of simple epithelium are: 1 simple squamous; 2 simple cuboidal; 3 simple columnar; and 4 pseudostratified.
Simple squamous epithelium cells are flat in shape and arranged in a single layer. This single layer is thin enough to form a membrane that compounds can move through via passive diffusion. This epithelial type is found in the walls of capillaries, linings of the pericardium, and the linings of the alveoli of the lungs.
Simple cuboidal epithelium consists of a single layer cells that are as tall as they are wide. The important functions of the simple cuboidal epithelium are secretion and absorption. This epithelial type is found in the small collecting ducts of the kidneys, pancreas, and salivary glands.
Simple columnar epithelium is a single row of tall, closely packed cells, aligned in a row. These cells are found in areas with high secretory function such as the wall of the stomach , or absorptive areas as in small intestine.
They possess cellular extensions e. They form the covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands.
They perform a variety of functions that include protection, secretion, absorption , excretion, filtration, diffusion , and sensory reception. The cells in epithelial tissue are tightly packed together with very little intercellular matrix. All the cells are attached to the underlying basement membrane, but the nuclei are at different heights, giving the appearance of a 'stratified' epithelium.
Hence this is a 'pseudostratified' epithelium, as it is in reality a single layer of cells. Make sure you can identify the goblet cells. What shape do the rest of the epithelial cells have? Epithelium: Types of simple epithelium Squamous Squamous means scale-like.
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