BMS 300 1st Edition Lecture 12Outline of Last Lecture I. Protein targeting to the endoplasmic reticulum -protein translocator 1. secreted lyosomal proteins2. transmembrane protein-glycosylating in the ER -------------------------------------------------------------------------------------------------------------------------------II. Cells functioning in concert -tissues1. group of similar cells performing similar functionsIII. Types -epithelia -connective-muscle -nervous IV. Epithelia -form borders/interfaces V. Characteristics of Epithelia -continuous layer of cells These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-attached to basal lamina -oriented cells -able to replicate -cell functions VI. Epithelia junctions Outline of Current Lecture VII. Cell junctioning in epithelia-anchoring 1. hemidesosomes-basal lamina-integrin 2. desmosomes-cell to cell-cadherin -occluding 1. tight -communicating- GAP 1. connexons composed of 6 connexins VIII. Glandular epithelium-exocrine/duct gland -surface -duct-secretory -adenocarcinoma IX. Connective tissue—scattered cells connected by the extracellular matrix they secrete-connective tissue proper 1. fibrocytes-cartilage 1. chondrocytes -bone 1. osteocytes -blood1. hematopoietic stem cells X. Skin as an organ -epidermis Current LectureAnchoring Junctions-Two types of anchoring junctions 1. hemidesmosomes >anchors epitheliac cells to the underlying extracellular proteins 2. desmosomes -when you add the transmembrane proteins they form “tight junctions” which prevent movement within the gaps of the cells -tight junctions are also occluding junctions -there’s a cadherin that ties the two cells together Keratin: intermediate filament protein Integrin’s: extracellular secreted proteins of the basal lamina -there is also a GAP junction -this is a communicating junction -you need to have proteins to anchor things to the basal lamina-the gap junction has protein bridges which extend across gap junctions and they form a channel between the cells -also called a “cytoplasmic bridge” for cytoplasmic continuity -they are for very small molecules -these gap junctions contain hundreds of connexons -each of these connexons contains 6 proteins which are called connexins For Example: -we might run into Ca2+-when Ca2+ comes in it may activate the suicidal mechanism of these cells -on the cytoplasmic side there may be receptors which will let the channels shut as to not let the cell get through -therefore they can control the movement of molecules across these cells Glandular Epithelium -epithelial cells forming an exocrine gland -an exocrine gland is a ducted gland which means the duct is formed by the epithelium Examples: 1. Salvatory>the duct epithelium takes the Na+ and Cl- out and then the K+ and HCO3- in>when you sweat a lot the reason it seems salty is because there isn’t time for the epithelium to move the Na+ and Cl- out 2. Mammary >mammary is the same as salvatory but with movement of the muscles in the breast as well 3. Pancreatic >adenocarcinoma: is a glandular epithelium cell that has become an out of control cancer -there’s a glandular/secretory epithelium that attaches the two pieces of cells together Connective Tissue -remarkably different from epithelia -characterized by extracellular matrix 1. connective tissue properfibrocyle>tendons, ligaments, dermis of the skin 2. cartilagechondrocyte >hyaline, elastic, fibrous 3. boneosteocytes >secretes calcium phosphate 4. bloodhematopoietic stem cells -there are extracellular proteins that form a matrix in which the connective tissues of the cells are
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