BSCI LECTURE NOTES:2/22/13- Translation occurs in the cytoplasmo Includes all 3 types of RNA% rRNA, tRNA, mRNA- tRNAo Cleverly shaped with amino acido The "tail" of the tRNA and 3 base sequences called the ANTICODON attached to the "head" of the tRNAo When the ribosome covers a codon on the mRNA, tRNA with complementary bases (ANTICODON) will attach to the codon bringing along an amino acido The anticodons are the same as the triplets except the triplets contain a "T" and the tRNA replaces it with a "U"- TISSUES = Tissue Levelo Composed of similar cells put together to perform specific functionso Most cells in the human body aggregate to form tissues => most cells are not independent => connect with other cells- 4 Primary Tissueso Epithelial%o Connectiveo Muscleo Nervous- Epithelialo Polarityo Avascular but have a high regenerative capacity Only if the epithelial tissues are supported by vascularized connective tissueso ALL epithelial tissues are supported by a basement membrane which acts as a selective membrane to regulate substances that diffuse from the underlying connective tissue to the overlying epithelial tissue- 2 Classes of Epithelialo Membranous (sheet-like) Simple- Single layer- SQUAMOUSo A single layer of flat scale-like cells with flattened nuclei placed underneath the apical surface of the cellso Forms part of the filtration membrane in the nephrons in the kidneyso Part of the respiratory membrane in the lungso Lines structures in the circulatory system Cardiovascular- Blood circulation Lymphatic- Lymph circulation o Line structures of the circulatory system is specifically referred to as ENDOTHELIUM Composition Location o Forms part of the serous membraneo Specifically referred to as the MESOTHELIUSM Composition Location - Cuboidal o A single layer of cube-like cells with centrally-placed spherical nuclei o Location Lines the tubules of the nephrons in the kidney Secretion Reabsorption during urine formationo Outer layer surrounding each ovary GERMINAL EPITHELIAL- Columnaro Single layer of tail cells with elongated nuclei placed closer to the basal surface of the cells o Non-ciliated Lines the stomach and anal canal Stomach small intestines large intestines rectum anal canal Small intestines - Cells express microvilli o Increase surface area for absorption in the small intestineso Ciliated Come with goblet cells- Secrete polysaccharides called MUCINo Interacts with water to form mucus Lines the bronchi (tube-like structure leading to lungs) Cilia beat to create a unidirectional current that moves mucus away from the lungso Part of the respiratory system Goblet cells secrete mucus which is moved/propelled by unidirectional current produced by the cilia o Fallopian tubes Cilia beat to create unidirectional currentthat moves ovum (egg) or conceptus from the fallopian tube to the uterus Stratified - Named for the epithelial cell type on the apical surface o Glandular (aggregate of secretory cells)2/25/13- Pseudostratified Columnar Epithelial Tissueo Single layer of tall cells of different heights Nuclei appear at different heights giving the false appearance of stratification (false appearance of layers)o Ciliated Endowed with GOBLET CELLS is specifically referred to as the respiratory epithelium - Composition- Location o Lines most of the structures in the respiratory systemo Beat to create a unidirectional current that moves mucus o Non-Ciliated Lines the ducts in the male reproductive system Epidydimides, vasa deferentia, ejactulatory ducts, urethra Confers protection to these ducts ^^^ Thicker than simple epithelial and when sperm are not moved out of the male ducts, the pseudostratified non ciliated columnar epithelial cells engulf and destroy sperm- Stratified epithelial tissueso Names for the cell type on the apical surface of the stratified epitheliumo Stratified surface Several layers of cells with scale-like (i.e. squamous) apical cells o SQUAMOUS Keratinized - Apical cells are impregnated with a tough fibrous protein called KERATIN- Cells are coated with glycolipids - Abusive-resistant and water-proof- Locationo EPIDERMIS Non-keratinized- Forms part of the mucus membrane which lines most of the structures in the tracts of the bodyo Tracts have openings to the exterior o Into skin = non-keratinized to keratinized - Lines the entry/exit structures of the tracts where this epithelium allows for movement of fluids into the structures and also allows for movement of structures through the tract - Confers protection to the structures of the lines o Columnar and Cuboidal Epithelial lining of ducts which lead from exocrine glands whenthey confer protection to the internal surface of the ducts - Transitional Epithelial o Lines the structures that convey/store urine Uterus Bladder Urethra When these structures are empty, transitional epithelium encroaches into the lumen (open space)- 6 layers with cuboidal-like cells on the apical surface- As urine flows into these structures the transitional epithelium undergoes a “transition” and changes from 6layers to 3 layers - Cuboidal-like cells become squamous cells - This increases the capacity of the lumen of these structures3/1/ 13- Ligaments connect bones at the site of joints- Dense irregular CTo Bundles of collage fibers arranged in an irregular fashion They face all directions HENCE dense irregular CT can withstand pull/stress/force in applied in several directions o Location Forms the reticular layer of the dermis- Papillary layer of dermis is composed of areolar CTo Provides nutrients to the overlying avascular epidermiso Highly vascularized o Forms the fibrous capsules that surround organs in the bodyo Forms the perichondriac which surrounds the avascular cartilage o Forms the periostrium that surrounds bones and provides blood vessels/nutrients to the bone tissue- 3rd type of dense CT = ELASTIC CONNECTIVE TISSUEo Bundles of collages fibers o Bundles of elastic fibers Provide the stretch-recoil property of the elastic CTo Location In the ligaments flava which run alongside there vertebral column and they allow for stretching of the vertebral column (as when one bends) and they recoil to the return the vertebralcolumn to its normal position when one - 2nd class of CT CARTILAGE o Secreted by chondroblasts o Consistency of the matric semi solido Matured
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