FNDH 400- Exam 2

What is the maturation and life cycle of enterocytes (crypts, villi, sloughing etc.) - correct answer The crypts which located in the pits of villi contain stem cells that can differentiate to enterocytes, and the enterocytes mature as they migrate up. The life cycle of enterocytes is 72 hours. Once enterocytes have reached the top of villi, they are sloughed off, and are either digested or excreted in feces. Uptake - correct answer compounds being transported into enterocytes Absorption - correct answer compounds being transported from enterocytes into circulation/lymph Passive Transport - correct answer does not require energy from ATP, and moves with concentration gradient 1. Simple diffusion - solutes move from an area of higher concentration to an area of lower concentration without the aid of proteins in membrane 2. Facilitated diffusion - solutes move from an area of higher concentration to an area of lower concentration with assistance of membrane proteins 3. Osmosis - water moves from an area of lower concentration to an area of higher concentration Active transport - correct answer requires energy in the form of ATP, and moves against concentration gradient 1. Active carrier transport - solutes move from an area of lower concentration to an area of higher concentration, use carrier/transport protein to help compounds get across membrane Endocytosis - correct answer substances are taken up into cell in vesicles formed from the cell membrane Type 1 Diabetes - correct answer the beta cells in pancreas are not capable of producing enough insulin, so it doesn't bind to the insulin receptors and thus does not activate GLUT 4 to move to the surface of muscle and adipose cells. This means limited glucose is taken up by GLUT 4. Type 2 Diabetes - correct answer enough insulin is produced by pancreatic beta cells and binds to the insulin receptor, GLUT4 does not move to the surface of muscle and adipose cells due to the insulin-resistance, as a result, little glucose is taken up into cell Glycemic Index - correct answer the relative change in blood glucose after consumption of 50g of carbohydrates in a test food compared to 50g of carbohydrates of reference food (white bread or glucose) Glycemic Load - correct answer incorporates serving size, use if you are measuring a whole food that takes into account serving size How Carbs are taken up into enterocytes, altered or repackaged, and absorbed - correct answer Monosaccharides are taken up through transporters How Proteins are taken up into enterocytes, altered or repackaged, and absorbed - correct answer Dipeptides and tripeptides are transported through a transporter, and amino acids are taken up through a variety of transporters. Inside the enterocytes, peptides are cleaved to amino acids by peptidases. Then all amino acids are transported from enterocytes into capillaries How Lipids are taken up into enterocytes, altered or repackaged, and absorbed - correct answer Mixed Micelles make it to the brush border, components make it into the enterocyte. SCFA and MCFAs are not reesterfied and are diffused into the capillaries and bind to the protein Albumin. Long Chain Fatty Acids are reesterified into phosphatidylcholine, triglycerides, and cholesterol ester and are packaged into chylomicrons and absorbed through the lacteal because they are too large for capillaries. How Carbs are transported to the liver after absorption - correct answer Monosaccharides are transported to the liver through the portal vein. How Proteins are transported to the liver after absorption - correct answer Amino acids are transported to the liver through the portal vein. How Lipids are transported to the liver after absorption - correct answer SC and MCFAs are transported by the portal vein. Long Chain Fatty Acids are packaged into a chylomicron and is transported to the lacteal. The chylomicron enter general circulation where lipoprotein lipase cleaves triglycerides into fatty acids, a Chylomicron Remnant. The chylomicron Remnant is endocytosed into the liver. Have an integrated understanding of lipoproteins (where formed, composition relative to other lipoproteins, how one is formed from the other etc.) - correct answer Lipoproteins are a cluster of lipids and proteins that transport lipids in the lymph and blood. Lipoproteins are Chylomicron, Chylomicron Remnant, VLDL, IDL, LDL, and HDL. Chylomicrons are cleaved by LPL, chylomicron remnants are formed, and are endocytosed by the liver. Lipids in the liver are used to form VLDL, LPL process occurs for VLDL to IDL to LDL. LDL transports cholesterol and amino acids to target tissue. HDL picks up cholesterol from tissue/blood vessels back to liver LPL is the enzyme that removes fatty acids from the triglycerides of the lipoprotein so that these fatty acids can be taken up into tissues. Each time the LPL cleaves fatty acids from a lipoprotein, it gets smaller in its diameter and more dense. Chylomicrons are the lowest density, but the biggest diameter and HDL has the most dense, but the smallest diameter. The larger the lipoprotein the higher % of triglycerides and lower % of proteins. The same amount of cholesterol is in VLDL, IDL, and LDL, however, because LDL has the least amount of triglycerides, after being cleaved, it has a greater mass % of cholesterol within it. What's the difference between cholesterol and lipoproteins as it relates to good and bad cholesterol - correct answer There is no "good" and "bad" cholesterol. LDL is a bad cholesterol transporter (Oxidized, foam cells, fatty streak, blocks arteries). HDL is a good cholesterol transporter which transport cholesterol back to the liver to be stored or metabolized Role of lipoproteins in the development/prevention of atherosclerosis - correct answer LDL enters endothelium where it is oxidized. The oxidized LDL is engulfed by white blood cells. Formation of foam cells. Foam cells accumulate so much LDL they die. Form fatty streaks. Fatty streak can grow until it blocks artery HDL - Reverse cholesterol transport- brings cholesterol back to liver Peptic Ulcers - correct answer Mucus layer of stomach or duodenum becomes too thin, acid can erode the cells causing lesions. Caused by acid-resistant bacteria called Helicobacter pylori. Frequent use of anti-inflammatory drugs (NSAIDS) inhibit production of protective eicosanoids Gallstones - correct answer Formed when bile hardens in the gallbladder which blocks bile ducts. Primary treatment is cholecystectomy- removal of gallbladder in which bile flows directly from the liver into the small intestine. Irritable Bowel Syndrome - correct answer Syndrome: group of symptoms (not a disease). the colon does not function properly Inflammatory Bowel Disease - correct answer A number of inflammatory conditions in the intestine. Crohn's disease: occurs anywhere in the GI but commonly in last part of ileum. Ulcerative colitis: ulcers in lining of colon and/or rectum. Thought to be an autoimmune response Celiac Disease and Gluten - correct answer Gluten: a protein that is bound to starch in the endosperm of grain