BIOL 112 1st Edition Lec-ture 16 Outline of Last Lecture I. Background of Form/FunctionII. The Digestive SystemIII. The Human Digestive System A. PharynxB. EsophagusC. StomachD. Small IntestineIV. AbsorptionOutline of Current LectureV. Significance of LiverVI. Absorption of Water and SaltsVII. Circulatory SystemsVIII. Components of Circulation SystemCurrent LectureI. Significance of Liver•1st major organ for blood and lymph coming from intestines•Hepatic-Portal Shunt: Blood from the intestines goes through the liverbefore it goes to the rest of the body, liver acts as a filter and a buffer•Liver controls nutrient concentrations in blood, also detoxifies blood from intestines, takes out things that are not healthy and destroys them to regulate blood streamThese 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.II. Absorption of Water and Salts•Occurs in Large Intestine (Colon)•End of ileum connects to colon through another sphincter: ileocaecal sphincter•Caecum -In humans, this in-cludes the appendix -Blind pouch - in someanimals, this is a fer-mentation site for sym-biotic bacteria and pro-tists digesting cellulose•Colon -Chyme coated withthick mucus -Salts removed by active transport through intestinal wall, sent to blood -Water is removed osmotically when salts are transported out -About 90% of water is removed•Removal of water coupled with peristaltic movements that pack chyme into a compact mass: feces -About 30% of feces is dead bacteria•Feces propelled to rectum•Anus is final sphincterIII. Circulatory Systems•Major function: transport of materials throughout body•Other “services”:•Gas Exchange: Transports gasses exchanged for respiration•Nutrients: Materials picked up by digestive system are distributed throughout body•Wastes: Products to be removed by excre-tory system•Hormones: Communication and controlthroughout body•Body Defenses: Inflammatory/Immune Sys-tems•Types of Circulatory Systems:•Open Circulation: arthropods, molluscs.Blood is not completely enclosed in ves-sels throughout circuit to/from heart.Blood empties into sacs called sinuseswhich surround many major organs•Closed Circulation: annelids, chordates(us). Blood is contained entirely in ves-sels in circuit to/from heart. Regarded asmore efficient because higher bloodpressure is maintained in circuit.IV. Components of Circulation System•The Heart as Pump•Human heart: right/left atrium; right/left ventricle•Between each atrium and ventricle: valves; permits one-way flow of blood from each atrium into each ventricle only Atrioventricular Valves -Left - Mitral Valve -Right - Tricuspid Valve•Between each ventricle and blood vessel: Semilunar Valves•Heartbeat: “thub-lub” -Thub: AV valves snap shut after atria contract -Lub: Semilunar valves snap shut after ventricles
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