Cellular organelles and characteristics of epithelial tissue

[Aida]

Please help!!!! Ist quest. Name and describe the major cellular organelles in one paragraph? List characteristics of epithelial tissue in one paragraph? I have my answers but need help in putting it in one paragraph.

[biostudent84]

The Nucleus is the largest organelle in the cell. It's main responsibility is overall controll and management of the cell. Next is the Endoplasmic Reticulum, which has an outer membrane continuous with the outer membrane of the nucleus. The ER is made up of both rough and smooth sections. The smooth synthesizes fatty acids and phospholipids, and the rough synthesizes proteins of plasma membrane. In charge of maintenence are the Lysosomes and Peroxisomes. Lysosomes are in charge of the destruction of obsolete parts of the cell and the degredation of polymers into monomers. Peroxisomes, found in animal cells only, contain oxidase and catalase. The oxidase use oxygen to oxidize organic molecules, and the catalase breaks down the toxic Hydrogen Peroxide produced by the oxidase. Finally, the Mitochondria, which is oval-shaped and surrounded by a double membrane, inside membrane is folded into “shelves” (cristae) to surround the inner region (matrix). It is in charge of ATP (adenosine triphosphate) production through Krebs Cycle and electron transport system.

[biostudent84]

Epithelial tissue is one of the four major classes of tissue in the body. It has the properties of any or all of the following: ciliated, absorptive, and secretory cells. The major function of epethilial tissue is to line and protect vital cells in the body. The single largest example of this is the upper layers of the skin. These are layered squamous cells which are designed to keep the body protected from pathogens.

[Aida]

Thank you for your help. It is greartly appreciated.[/img][/code]

[wombat]

Wouldn't epithelial tissue also contain centrioles and leucoplasts?

[MrMistery]

centrioles yes, but leucoplasts are only found in plant cells...

[wombat]

mmk.

i've also discovered that the epithelium in one's intestine contains lysosomes, and epithelium in one's dermis contains chromoplasts.

[MrMistery]

no!
you mix up plant epithelial tissues with animal epithelial tissues. plastids(be they leucoplasts, chloroplasts, chromoplasts or whatever) are only found in plants and algae

[Dr.Stein]

Actually, the structure of epithelial cell depends on its function, whether protection, secretion, absorption, or something else. Thus, major organelle(s) appear in one epithelium could be different ffrom another one.

I think wombat mixed up between "chromoplast" and "chromatophore", which he refers to "chromatophore", epithelium which contains pigment? Yes, the basal part of skin epithelium (just upperside of dermis, called as stratum Malpighi) contains pigment cells, especially melanin, thus it is called as melanophore.

Colorful animals have another type of pigmentation. However all pigmentation is controlled by single hormone, MSH, secreted by intermedial lobe of pituitary.