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A&P EXAM 2
Epithelial
Question | Answer |
---|---|
Tight junction | Is an area where the plasma membranes of adjacent cells are fused together. These junctions prevent underlying tissues from harmful substances by restricting the movement of substances into cells. |
Where are tight junctions found? | The stomach, intestine and urinary bladder. |
Adherens junction | Created when trans-membrane proteins anchored to a dense plaque of proteins inside the cell connect the adjacent cell membranes together. Also micro filaments extend from the plaque into the cytosol. |
Desmosome | Is similar in structure to adherens junction. Except that intermediate filaments extend into the cytosol. These junctions help provide stability to tissues and gives the skin its ability to endure stretching and other mechanical stresses without tearing. |
Where are desmosome junctions found? | In the skin and in between muscle cells. |
Gap Junctions | Open communication channel protein, connexons. Allows ions and other molecules to pass freely. Also allows electrical impulses to pass from one cell to another. |
Where are gap junctions most abundant? | In some types of muscle tissues |
Simple Squamous locations | Lining of ventral body cavities (mesothelium) and lining of heart & blood vessels (endothelium) |
Simple Squamous functions | Reduce friction, control vessel permeability, Absorption & secretion |
Simple Cubodial locations | Glands & ducts (thyroid) and kidney tubules |
Simple Cubodial functions | Secretion & absorption |
Simple Columnar locations | Lining of stomach, intestine, uterine tubes, collecting ducts (kidney) |
Simple Columnar functions | Protection, Secretion & Asorption |
Stratified Squamous locations | Skin, mouth, throat, esophagus, rectum & anus, vagina |
Stratified Squamous functions | Protection against abrasion, pathogens, and chemical |
Endocrine Glands functions | Release secretion into interstitial fluid such as hormones. ( regulates physiology and help maintain homeostasis) |
Where are endocrine glands found | pituitary gland, thyroid gland, parathyroid, adrenal gland, pineal gland, part of pancreas, ovaries/testes |
Exocrine gland functions | Release secretion into ducts & released onto an epithelial surface |
Exocrine glands are found in | Sweat glands, tear glands, digestive glands and salivary glands |
Apocrine secretion | Pinches off a portion of cell for its secretion, the plasma membrane will reseal. Has little damage to cell. |
Merocrine secretion | Ribosomes attached to the rough ER, processed sorted and packaged by the golgi, then released via exoctosis. No damage to the cell. |
Holocrine secretion | Accumulates the secretory products in their cytosol. As cell matures, it ruptures and the secretory product is released onto the surface. Cell division replaces lost cell. Alot of damage to cell |
Pseudo-stratified Columnar locations | Respiratory tracts: nasal cavity, trachea, bronchi |
Pseudo-stratified Columnar functions | Protection Secretion Cilia Mucus movement |
Transitional Epithelia locations | Special type of stratified epithelial Bladder & ureters |
Hemidesmosome | provides strong attachments between cells and other extracellular materials such as the basement membrane of epithelial tissue. Most abundant in tissues that undergo constant frictional forces |
General features of Epithelial Tissues | Cells are arranged in sheets, densely packed, many cell junctions are present, mitosis occurs frequently, Epithelial cells attach to a basement membrane, Epithelial tissue is avascular but does have a nerve supply |
Where are epithelial tissues located | Exposed body surface, lining of passageways that communicate with extra surface, lining of body cavities and blood vessels |
What are the functions of Epithelial tissue | Physical protection, control permeability, provide sensation, and produce secretion |
What is a gland? | A gland is a single cell or a mass of epithelial cells adapted for secretion |