Epithelial cells

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What is the structure of epithelial tissue?

• large sheets of cells covering all the surfaces of the body exposed to the outside world and lining the outside of organs; highly cellular, with little or no extracellular material presented between cells

What is the function of epitelial tissue?

• provide the body’s first line of protection from physical, chemical, and biological wear and tear; gatekeepers of the body controlling permeability and allowing selective transfer of materials across a physical barrier; many can secrete mucous and other chemical compounds

What is the tissue membrane?

A thin layer or sheet of cells that covers the outside of the body (for example: skin), the organs (for example, pericardium), internal passageways that lead to exterior of the body (for example, mucosa of stomach), and the lining of the moveable joint cavities

What are the two basic types of tissue membrane

connective and epithelial tissue

What is a gap junction?

• allows cytoplasmic communications to occur between cells

What is a tight junction?

• forms an impermeable barrier between cells

What is a anchoring junction?

• mechanically attaches adjacent cells to each other or to the basement membrane

What is the structure of a gland?

• made up of one or more cells modified to synthesize and secrete chemical substances.

What are most glands made up of?

Epithelial cells

What are the secretions of endocrine glands called?

hormones

Secretions of endocrine glands include:

• Mucous, sweat, saliva, and breast milk

What is a duct?

A tube or passageway that releases something

What are squamous cells?

• flat, scale-like cells that form protective layers on skin surfaces and line many internal body passages, like the respiratory and digestive tracts, cervix, and bladder, acting as a barrier against damage, infection, and water loss

What are Cuboidal cells?

• cube-shaped, with their height, width, and depth being approximately equal.

What are Columnar cells

• are taller than they are wide, shaped like columns, and their nuclei are often elongated and located near the base of the cell.

What are goblet cells?

specialized glandular cells, often found interspersed within columnar epithelial cells, particularly in the lining of the respiratory and gastrointestinal tracts.

Function of goblet cells

synthesize and secrete mucin, a glycoprotein.