BCMB 230 1st Edition Lecture 24 Outline of Last Lecture I Plasma pH Regulation II Reabsorption and Secretion III Bicarbonate Handling pH in the Kidney IV Digestive System Outline of Current Lecture I Absorption II Lymphatic System III Control of Digestive System IV Functions of Liver V Endocrine System Current Lecture I Absorption Absorption moving digested material from lumen cavity space of digestive organs into blood Most absorption occurs in the small intestine Water absorption happens in the stomach Maintain high glucose levels in plasma The body wants to absorb the maximum amount so it requires secondary active transport with Na Amino acids do the same thing Also need secondary active transport Fructose not present in the plasma in very high levels use facilitated diffusion Fatty acids monoglycerides Can get a micelle droplet of fatty acid because of amphipathic nature emulsion droplets and fat droplets membrane is permeable to fat so no transporters are needed within epithelial cell of intestines synthesize triglycerides within the endoplasmic reticulum to get them out of the intestine don t want buildup so need to move them out of the cells into the rest of the body moved out of the cell by exocytosis now have a chylomicron Main transport system to get it from interstitial fluid to adipose cells under skin somewhere II Lymphatic System These 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 has a series of vessels like capillaries and veins of circulatory system lymph capillaries small thin walled very permeable have pores that are valved that allow material to move into but not out of them lymphatic vessels much like veins In digestive system these lymphatic capillaries have a special name lacteals Have to make and break down fat several times to transport them because we don t have a transporter for it III Control of Digestive System movement controlled by smooth muscle can be regulated secretion regulate through sympathetic nervous system digestion control to an extent by controlling muscles and glands but if there is too much food we can t not digest it try to maximize this absorption can t regulate intake of nutrients and calories try to maximize this Two nervous systems that work in the digestive system Have nerves in the wall called plexus collectively call this network of nerves as the enteric nervous system Have both long and short neural reflexes 3 different ways to control Long neural reflex Short neural reflex Hormones come from GI tract four main ones gastrin CCK secretin and GIP Gastrin is from the stomach gastric hormone other three come from small intestine intestinal hormone Gastric hormone stimulate stomach Intestinal hormones inhibit stomach promote things important for intestine particularly secretion of various enzymes into small intestine Control of HCl Secretion During a Meal separate through stimuli cephalic phase head senses thought of food start to control secretion and movement results in increase of HCl secretion stimuli come from stomach gastric phase distension increase in peptides decrease in H concentration results in increase of HCl secretion stimuli come from intestine intestinal phase distension increase in H concentration increase in osmolarity results in decrease of HCl secretion Common bile duct and pancreatic duct share the same opening sphincter of Oddi controls this can control secretion of bile salts and bicarbonate and pancreatic enzymes done by one of the intestinal hormones IV Functions of the Liver important in digestion provide bile salts that helps with fat absorption important in blood clotting provide proteins important in osmotic balance provides albumin steroid hormones come primarily from two glands from gonads ovaries or testes testosterone estrogen or adrenal cortex also have steroids aldoseterone cortisone cortisol etc in females testosterone from adrenal cortex is important in sex drive of females imbalance can cause a woman to develop manly characteristics estrogen levels are falling hormones tend to be bound to protein not soluble in water liver also involved in immune system makes proteins involved with immune system Major symptoms of liver damage jaundice if the whites of the eyes are white it is just dietary if the whites of the eyes are yellow check for liver function V Endocrine System If there is an issue disease in the endocrine system can cause problems of secretion at gland itself or can have problems at the target cell which is a problem in responsiveness with secretion there can be too little which is a hyposecretion or too much which is a hypersecretion take blood sample to determine which one different categories in both of these depending on where the issue is some glands are controlled by hormones these hormones are called tropic hormones mostly coming from anterior pituitary which is controlled by hormones from the hypothalamus anterior pituitary controls parts of adrenal cortex the gonads thyroid Secretion can be primary secondary or tertiary not with responsiveness Primary is a defect in the gland that produces the hormone Hormone levels appropriate Response reduced hyporesponsiveness Response increase hyperresonsiveness