BIOS 256Midterm Review A&P IV

-What are the components and features of the stomach? The four regions of the stomach are the cardia, fundus, body, and pyloric part. Functions of the Stomach 1.Mixes saliva, food, and gastric juice to form chyme. 2. ...

-What are the components and features of the stomach? The four regions of the stomach are the cardia, fundus, body, and pyloric part. Functions of the Stomach 1.Mixes saliva, food, and gastric juice to form chyme. 2.Serves as reservoir for food before release into small intestine. 3.Secretes gastric juice, which contains HCl (kills bacteria and denatures proteins), pepsin (begins the digestion of proteins), intrinsic factor (aids absorption of vitamin B12), and gastric lipase (aids digestion of triglycerides). 4.Secretes gastrin into blood. -What ducts does bile pass through when it leaves the gallbladder? the Cystic duct that forms the common bile duct. -The Pancreas secretes many enzymes – what are they, and what do they aide in digesting? Pancreatic enzymes digest starches (polysaccharides), proteins, triglycerides, and nucleic acids. Pancreatic juice buffers acidic gastric juice in chyme, stops the action of pepsin from the stomach, creates the proper pH for digestion in the small intestine, and participates in the digestion of carbohydrates, proteins, triglycerides, and nucleic acids. What are the different sphincters that regulate flow throughout the digestive tract? Four distinct smooth muscle sphincters are present in the GI tract: -lower esophageal sphincter (LES)- is a muscle that separates the esophagus from the stomach. It acts like a valve that normally stays tightly closed to prevent contents in the stomach from backing up into the esophagus. -pyloric sphincter (PS)- is a band of smooth muscle that controls the movement of partially digested food and juices from the pylorus into the duodenum. -ileocecal sphincter (ICS)- is a sphincter muscle situated at the junction of the ileum (last portion of your small intestine) and the colon (first portion of your large intestine). Its function is to allow digested food materials to pass from the small intestine into your large intestine. -internal anal sphincter (IAS)- is an involuntary smooth muscle sphincter located at the distal extremity of the gastrointestinal (GI) tract. It is formed by a thickening of the circular muscle layer and is surrounded by skeletal muscle of the external anal sphincter (EAS). Where does 90% of nutrition and water get absorbed at? What anatomical structures aide in this absorption? by the small intestine. Absorption of the majority of nutrients takes place in the jejunum Mainly in the first half of the jejunum, the majority (about 90%) of nutrient absorption occurs involving proteins, carbohydrates, vitamins, and minerals Amphipathic molecules are compounds with both polar and non-polar regions, such as bile salts. What is the function of bile salts? Bile salts emulsify fats and break them down into smaller particles which gives the enzyme lipase a greater surface area to act on during digestion of fats. Carbohydrate digestion begins in the mouth with salivary amylase. What is bilirubin? Where is it excreted from? Bilirubin is secreted in the liver. It gives feces its brown color. It is made through the breakdown of old red blood cells and is excreted out by urine or feces.  Know the anatomical names of all of the GI tract. What are the 3 regions of the small intestine? What regions make up the colon (large intestine)?  <-“GI tract” Duodenum, jejunum, and the ileum.= The first part, called the duodenum, connects to the stomach. The middle part is the jejunum. The third part, called the ileum, attaches to the colon Sections of the colon are:  The ascending colon including the cecum and appendix.  The transverse colon including the colic flexures and transverse mesocolon.  The descending colon.  The sigmoid colon – the s-shaped region of the large intestine.  The rectum.  Know the functions of the liver. . Bile production and excretion, Excretion of bilirubin, cholesterol, hormones, and drugs, Metabolism of fats, proteins, and carbohydrates, Enzyme activation, Storage of glycogen, vitamins, and minerals, Synthesis of plasma proteins, such as albumin, and clotting factors, and Blood detoxification and purification  What are the 3 glands that secrete saliva and where are they located? Parotid= by the ear, submandibular= far back jar line , and sublingual= Under the tongue.  What are the layers of the GI tract? Mucosa, submucosa, muscularis and serosa.  The peritoneum is the largest serous membrane in the body – what are the different components of the peritoneum? 3 layers: The parietal peritoneum and visceral peritoneum layer, and the mesentery layer. The parietal layer is attached to the abdominal wall and the visceral layer is the inner layer that is wrapper around internal organs. The mesentery is the double layer of the visceral peritoneum.  Proteolytic enzymes are enzymes that break down chainlike molecules of proteins into shorter fragments. Which proteolytic enzymes are secreted by the pancreas? Lipase- this enzyme works together with bile, which your liver produces, to break down fats (lipids) in your diet. Amylase- This enzyme helps break down starches into sugars, which your body will use for energy. Protease- This enzyme breaks down protein in your diet.  Know the blood supply of the liver. The liver receives a blood supply from two sources. The first is the hepatic artery which delivers oxygenated blood from the general circulation. The second is the hepatic portal vein delivering deoxygenated blood from the small intestine containing nutrients.  What enzymes are responsible for digesting carbohydrates? What about lipids? Amylase breaks down carbohydrates and lipase break’s down lipids.  The stomach has 3 major cell types – Mucous cells, Parietal Cells and Chief cells. What do each of the secrete? [Know the table of Digestive activities within the stomach]. Parietal cells produce intrinsic factor (needed for absorption of B12) and hydrochloric acid which kills microbes in food; denatures proteins and coverts pepsinogen into pepsin Chief (zymogenic) cells secrete pepsinogen-(The activated form of pepsin) breaks down proteins into peptides. Chief cells also secrete gastric lipase which splits triglycerides into fatty acids and monoglycerides. Mucous cells secrete mucus and forms protective barrier that prevents digestion of the stomach wall.