Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Lecture 5: Transportation, Role of Hormones and the Nervous System, and Digestive Problems Transportation • How absorbed nutrients move around the body • What organs are involved in the process of transportation Nutrition 150 Shallin Busch, Ph.D. Vascular (Blood) System • Closed system of tubes • Pumped by heart • Transports most nutrients and fluids Lymphatic System • Collects fluid from outside of the vascular system into lymph vessels • Has no pump, but drains into vascular system • Transports most fats and fat-soluble vitamins The Vascular System The Liver Head and upper body Capillaries Hepatic vein Liver: 500 functions! Lungs Pulmonary vein Pulmonary artery - Receives blood from GI tract Hepatic artery Aorta Right side Hepatic vein - Filters wastes and digests toxins Left side Heart Hepatic artery Portal vein Liver Portal vein Digestive tract Lymph = = = = Arteries Capillaries Veins Lymph vessels Entire body Autonomic Nervous System • Nervous system that is not under voluntary control • Coordinates peristalsis, segmentation and opening and closing of sphincters etc. • Detects fullness of tract • Detects presence of acidity, fats, proteins, etc. • Stimulates production within and/or secretion by glands and cells -Stores and releases nutrients (glucose, fats, amino acids) Vessels - Produces bile Hormones Hormone: A chemical messenger that is secreted into the bloodstream by a gland and effects physiological processes at site remote from the gland Hormones coordinate many aspects of digestion. Hormones and Blood Sugar Insulin: Hormone produced by pancreas. Released when blood sugar is HIGH. Causes cell membranes to increase rate of glucose transport into cells. Glucagon: Hormone produced by pancreas. Released when blood sugar is LOW. Causes breakdown of liver glycogen into glucose, which is then released into the blood. Hunger Hunger: A physiological sensation that prompts us to eat. Coordinated in the brain. 1) Change in pressure or fullness of stomach and small intestine 2) Blood glucose level and the levels of the hormones that control it (insulin and glucagon) 3) Hormones neuropeptide Y and galanin stimulate hunger Appetite Appetite: A psychological desire to consume food. Controlled by the brain. 1) Perception of cues (smell, sight, sound, or thought of tasty food) 2) Association with event 3) Emotional state …brain causes releases of digestive enzymes Satiation 1) High protein foods have highest satiety value. High fat diets are more satiating than high carb diets. Food is more satiating than beverages. 2) Increased pressure on stomach and small intestine 3) Hormones leptin, cholecystokinin, and serotonin promote feelings of satiety Peptic Ulcers • “Area of the GI tract that has been eroded away by the acidic gastric juices of the stomach” (Thompson and Manore) • Helicobacter pylori infection • Use of nonsteroidal anti-inflammatories such as aspirin, ibuprofen, and naproxen sodium • Causes pain and bleeding (which can lead to anemia). Constipation • Absence of bowel movements at normal rate. Stools that are small, hard, and difficult to pass • Causes: Disorder of nervous system; change in diet, schedule, medication; dehydration; inadequate fiber • Risk: Pain, hemorrhoids Diarrhea • Frequent passage of loose watery stools • Causes: infection, chronic disease, bowel disorder, stress, food intolerance, reaction to medicine • Risks: Dehydration, loss of salts Irritable Bowel Syndrome • Symptoms: cramps, bloating, constipation or diarrhea • 20% of US population (more common in women) • No known cause, but linked to stress, caffeine, chocolate, wheat, alcohol, dairy, large meals, some medicine, immune response, female reproductive hormones, etc. • Treating symptoms and avoiding triggers, stress management, physical activity, small meals, high fiber diet, adequate water intake Gas Intestinal: Caused by digestion of food by bacteria in large intestine. Can be caused by ingestion of some food (carb rich) and also by a change in diet. Belching: Typically from swallowing air when eating. Eating too quickly, carbonated beverages, ill-fitting dentures, chewing gum