MBIOS 101 1nd Edition Lecture 25 Outline of Last Lecture - Lines of Defense1. Skin2. GI Tracta. Esophagusb. PharynxOutline of Current Lecture – 1. Stomach2. Pyloric sphincter 3. Small intestine4. Large intestine5. Appendix6. Rectum Current Lecture – First Line of Defense1. GI tract: mouth, salivary glands, epiglottis, esophagus, stomach, small intestine, large intestine, rectum2. Stomach – a. Produces HCl (causes pH 2)i. Kills most microbes but it may aid some organismsii. Examples of organisms aided 1. Helicobacter pylori: only grows in pH 2 and can lead to stomach ulcers 2. Parasite eggs use the acid sometimes to cause etching on the egg shell (cyst) this allows them to hatch in the small intestine (giardia lamblia: beaver’s fever)3. Some bacteria use the bacteria to activate them – E. Coli, Listeria, Salmonellaiii. Stomach also secretes water, mucus, and enzymes (protease lipase)3. Pyloric sphincter a. Located at the end of the stomach as the gateway between the stomach and small intestineb. Releases the chyme (food from stomach) into the small intestine – only releases 2Tablespoons per minute so that it is able to neutralize the pH 4. Small intestineThese 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.a. Stomach acid is at pH 2 which would burn a hole in the small intestine so the pancreas produce bicarbonate to bring the pH up to pH 7 i. First sign of pancreatic cancer is you cannot digest anythingii. Very hard to cureb. The big pH change kills a lot of bacteria c. Bile is also added to the chyme via the pancreatic duct (bile surrounds lipids and keeps them in the solution (think of oil and vinegar and how they separate- we are trying to avoid this)d. Bile also can destroy bacteriae. Small intestine also produce water and mucusf. Bile is stored in the gallbladderg. Microvilli allow for maximum absorption h. Most organisms are unable to cross over the microvillii. Exceptions that can cross i. Polioii. Hepatitisiii. Both can cross and travel through the blood stream5. Large intestine a. Absorption of some vitamins and materialsb. Home for NFO (over 500 species)i. They produce Vit K for us ii. Vit K is needed for blood clotsiii. Blood clots need 13 proteins to form (4 of these require Vit K)iv. Ex – profibrin (nonactive) fibrin (active)v. Also produces Biotin and panthothermic acid (2 water soluble vitamins)c. Also produces mucus to protect liningd. Lactose intolerance i. Can be allergic to either casein (protein) or milk sugar ii. Lactose in two sugars (galactose and glucose)iii. Enzyme lactase is used to break sugars apartiv. If there is not enough lactase, the lactose travels to the large intestine v. NFO love lactose they digest the lactose: produce acid, gas, have explosive replication, causes an environmental change you are miserablevi. People with lactose intolerance can eat yogurt and some hard cheeses 6. Appendix – off of the large intestine a. Appendicitis: high fever, nausea, painb. We are not exactly sure what the appendix doesc. Houses a lot of white blood cellsd. Part of the second line of defense and third line of defense e. No one knows why it gets infected7. Rectum a. Parasites (pin worm) lay egg in the fold of the bottom b. Causes irritation c. Most common in
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