BIO-Digestive System (1).pdf
Transcript
First Year End Review Digestive System Cavity:Peritoneal cavity or that the GI organs are within peritoneal membrane. Kidneys are retroperitoneal. Greater Omentum-fatty membrane covering stomach down to intestines. Mouth:...
First Year End Review Digestive System Cavity:Peritoneal cavity or that the GI organs are within peritoneal membrane. Kidneys are retroperitoneal. Greater Omentum-fatty membrane covering stomach down to intestines. Mouth: Teeth- Outer part=enamel; connective tissue on inside of teeth=dentin Enzyme in the Saliva-Amylase in saliva, begins carb digestion Pharynx:Food and air pass thru Esophagus:Posterior to trachea Stomach: Below diaphragm Parietal cells-Make 1. HCL (protein denaturation); 2. Intrinsic factor (needed to absorb Vit B12-eventually absorbed in ileum of SI) Chief cells-Make pepsinogen/pepsin (active form); Breaks peptide bonds. In other words, protein digestion-breaking proteins down to amino acids. Pyloric Sphincter-Distal end of ST. Controls St emptying into SI Small Intestine: Sections: Duodenum, Jejunum, ileum Lined by __Villi/Microvilli____________ Purpose: Increase surface area for better digestion and absorption (SI is primary site for absorption) Accessory Organs that secrete into duodenum: Liver-Makes bile for emulsifying lipids; Stores glycogen(stored glucose). Glycogen also stored in muscles. Makes plasma proteins such as albumin, clotting factors, angiotensinogen, complement proteins. Also converts ammonia(by-product of protein metabolism) into urea. GB-Stores, concentrates, and releases bile into duodenum via common bile duct. Pancreas-Makes amylase (carbs), lipase(lipids), and Trypsin(proteins) Large Intestine: Primary functions-Eliminate waste(feces), Absorption of water; Bacteria help extract B vitamins and Vitamin k. Fermenting of indigestible carbs such as cellulose leads to gas production Sections-Cecum(appendix attached to this)àascending colonàTransverseàDescending colonàSigmoid ColonàRectumàanus Blood Flow to and from GI Oxygenated blood comes from superior and inferior mesenteric arteries (from aorta to GI organs) All blood leaving GI organs goes through hepatic portal vein and is taken to Liver
