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The Human Body: From Food to Fuel BIOL 103, Chapter 4 (Part 2) Today’s Topics • Signaling Systems: Command, Control, and Defense – The Hormonal System – The Immune System • Influences on Digestion and Absorption – Psychological, Chemical, Bacterial Influences • Nutrition and GI Disorders Signaling Systems: Command, Control, Defense • Nervous system – Nerves carry info back and forth between tissues and the brain using chemical signals known as neurotransmitters. – The Central Nervous System (CNS) regulates GI activity in 2 ways: • Enteric nervous system: _______________________ • Autonomic nervous system: ____________________ _____________________________________________ – Responses to sight, smell, thought of food by ___________ __________________________________________________ Central Nervous System Signaling Systems: Command, Control, Defense • Hormonal system – Hormones: chemical messengers that travel in the bloodstream 1. _______________________________________ _______________________________________ 2. __________________________by sending messages to your CNS. • Thus, your CNS and hormones work together to coordinate movement and secretions of the GI tract. Signaling Systems: Command, Control, Defense • Immune System – Purpose: ____________________________________ – Role of GI tract • Immune Response – Macrophages: “big eaters” ___________________________ ______________________________________________________ – Natural killer cells: ____________________________________ • Location of lymphoid tissues – Lymphocytes: white blood cells present in __________________ » Some types produce antibodies – protein molecules that tag, neutralize, and help destroy bacteria/viruses or toxins. Immune System Influences on Digestion and Absorption • Psychological influences – Positive: Taste, smell, presentation of food – Negative: Stress, fear, depression • Example: • Chemical influences – Cooking __________________________________________ ______________________________________________________ ______________________________________________________ • Bacterial influences – HCl acid kills most bacteria • If lives food borne illnesses, gastritis, ulcer, etc. Nutrition and GI Disorders • Constipation (< 3x/week) – Hard, dry, infrequent stools – Reduced by _______________________________ ___________________________ • Diarrhea (> 3x/day) – Loose, watery, frequent stools – Symptom of diseases/infections ____________ – Can cause dehydration – _________________________________________ _______________________can help reduce diarrhea What is Dietary Fiber? • Fiber: a type of carbohydrate your body cannot digest with enzymes alone • 2 types: – Soluble fiber: __________________________________ • Can lower glucose, blood cholesterol • Fermented by bacteria in the colon into gases • Food sources: oatmeal, nuts, beans, lentils, apples, blueberries – Insoluble fiber: __________________________________ • Provides bulking absorbs water ease of defecation • Helps food move through your digestive system • Food sources: wheat, whole bread, brown rice, cucumbers, tomatoes Nutrition and GI Disorders • Diverticulosis – Pouches along colon develop as people age • 10-25% people pouches become infected – __________________reduces formation: • Low-fiber diet • Heartburn and GERD – Chronic heartburn GERD – Reduced by _________________________ – Smoking weakens the esophageal sphincter – Being overweight often worsens symptoms Nutrition and GI Disorders • Irritable Bowel Movement (IBS) – Causes abdominal pain, diarrhea, or constipation and cramps – Stress and certain foods aggravate the symptoms • Examples: milk, beans, chocolate, alcohol – Associated with reproductive hormones – Can usually be controlled by _________________ __________________________________________ • Stress management Nutrition and GI Disorders • Colorectal cancer: cancer in colon or rectum – ____ leading cause of cancer-related deaths in the US – Eating a lot of red meat and low fiber food can increase risks – __________________________may reduce risk: • Hypothesis: more fiber goes down the GI tract faster, dilution of carcinogens in a bulkier stool, etc… • BUT, human/animal studies do not support those theories. Nutrition and GI Disorders • Ulcers – Pain in the upper abdomen • Sore is in duodenum: duodenal ulcer • Sore is in stomach: gastric ulcer – Can cause nausea, vomiting, loss of appetite, and weight loss – Cause: ________________________________________ ________________________________________________ • Functional dyspepsia – Chronic pain in the upper abdomen ________________ _______________________________________________ – Treat with _____________________________________