121slide03 - The Human Body The Body is Made up of: The...

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Unformatted text preview: The Human Body The Body is Made up of: The Cells, Tissues, Organs, Systems Cells are organized into tissues Cells tissues Tissues are grouped together to form organ Tissues organ Body system Cell membrane: outer layer layer Composed of two layers Composed of phospholipids of Long lipid “tails” face Long each other toward the interior of the membrane interior Phosphate “heads” line Phosphate the interior and exterior surfaces of the membrane membrane Cholesterol and proteins Cholesterol are embedded within are Circulatory System Circulatory Circulatory System Circulatory The body’s main fluids The Blood Lymph Extra and intracellular fluids Circulatory System: Blood Circulatory As blood passes through the digestive As system, blood delivers oxygen and picks up most nutrients from the intestine intestine Protein, carbohydrates, Protein, water soluble vitamins and minerals Circulatory System: Lymph Circulatory Lymphatic vessels pick up most fats from Lymphatic the intestine the Then fats travel to the blood Circulatory System Circulatory All blood (with the nutrients) leaving the All digestive system is routed directly to the liver liver The Hormonal System The Hormones Chemicals secreted by glands in response to Chemicals conditions in the body that require regulation conditions Produced in specialized glands that travel in the Produced bloodstream to target organs in other parts of the body. body. Serve as chemical messengers = Act on organs to maintain constant conditions = The Hormonal System The Example: Pancreatic Hormones High blood glucose = insulin insulin Low blood glucose = glucagon Low glucagon The Hormonal and Nervous Systems Nervous Both the nervous and hormonal systems Both regulate hunger and affect appetite regulate Some hormones stimulate hunger Some hormones produce a feeling of satiety Why do we eat or not eat? Why Hunger: Regulated by internal cues Appetite: Strong drive to eat even when we’re not Strong hungry hungry Satiety: Anorexia: The Hormonal and Nervous Systems Nervous Hypothalamus region of the brain is the feeding center center Nerve cells in stomach and small intestine sense Nerve food and send message to hypothalamus food Hormones relay messages to the hypothalamus Nerve receptors in the stomach send signals to the Nerve hypothalamus to indicate if the stomach is full or empty empty Why Do We Want to Eat? Why PLAY Control of Appetite: Hunger and Satiety Figure 3.1 Definition: Homeostasis Homeostasis The maintenance of relatively constant internal The conditions—controlled by many “systems” in the body body Example: • Body Water Homeostasis Homeostasis Example: Calcium Calcium If you don’t milk, eat cheese, yogurt or other Calcium If containing foods, and you do NOT take a calcium supplement….will your blood levels be low? supplement….will What is it? DIGESTION DIGESTION The process by which food is broken down into a The form that can be absorbed by the intestine (large molecules to small molecules). molecules Where does it occur? What Happens to the Food We Eat? Eat? The food we eat undergoes three processes These processes occur in the gastrointestinal These tract. tract. DIGESTION DIGESTION Two Types 1. Physical/Mechanical Digestion Physical/Mechanical DIGESTION DIGESTION Two Types of Digestion: 2. Chemical Digestion 2. Chemical Digestion Digestion Basic anatomy of the GI tract mouth → esophagus → stomach → small mouth intestine → large intestine → rectum → anus anus Muscular Action of Digestion of Peristalsis 2 muscle layers working together moving food muscle molecules forward molecules PERISTALSIS PERISTALSIS MOUTH MOUTH What Happens Here? – This is where This digestion begins digestion – Mastication – Taste Buds: Digestion: Chewing Digestion: Figure 3.7a Digestion: Swallowing Digestion: Figure 3.8 Digestive Processes 2. ESOPHAGUS 2. ESOPHAGUS ESOPHAGUS What Happens Here? Esophagus is a long tube with that slowly, transfers Esophagus food to the stomach. food Swallow bolus into esophagus Swallow gastroesophageal sphincter separates the gastroesophageal esophagus from the stomach. esophagus Prevents the flow of food from the stomach back Prevents into the esophagus into Digestive Problems Digestive Heartburn Heartburn = gastroesophageal reflux (GERDS) gastroesophageal Antacids and acid controllers Indigestion Digestive Processes Digestive 3. STOMACH 3. Bolus becomes chyme chyme semi-solid product of mechanical and chemical semi-solid digestion in the stomach. digestion Digestion in the stomach includes Extensive mechanical digestion to mix food with Extensive gastric juice gastric Chemical digestion of proteins and fats Onto the small intestine Esophagus Esophagus Stomach Antrum Fundus Pylorus Small intestine DIGESTION DIGESTION How Does Food Break Down in the How Stomach? Stomach? ENZYMES A protein that causes a chemical reaction that protein to occur to Example: Example: • Lactase = • Lipase = Secretions of Digestion of Stomach has Stomach Gastric juice Gastric Hydrochloric acid (HCl): Pepsin: Gastric lipase: Mucus: Water: STOMACH STOMACH pH = 1.5 -2 ACIDIC pH ACIDIC Prevents bacteria growth Intestinal Disorders Intestinal Peptic ulcers are regions of the GI tract that have been eroded by HCL and pepsin. and The bacterium The Helicobacter pylori Helicobacter contributes to the production of both gastric and duodenal ulcers. ulcers. Digestion Digestion 4. SMALL INTESTINE 4. ~10 feet ~10 pH 5-6.5 Secretes majority of enzymes to Secretes break down food break 4. SMALL INTESTINE 4. 4. SMALL INTESTINE 4. Secretions of Digestion: Majority of digestion is here Enzymes: lipase, colipase, amylase, trypsin, Enzymes: chymotrypsin chymotrypsin Digestion: Accessory Organs Digestion: Surrounding the GI tract are several Surrounding accessory organs: accessory Liver: Pancreas Gall bladder: DIGESTION DIGESTION What About Foods that aren’t Digested or Absorbed? They visit the LARGE INTESTINE/COLON LARGE Body will pull water out of the digested food Body products made by the stomach forms a stool Stool gets Excreted Excreted 5. LARGE INTESTINE 5. What Happens Here? Chyme (undigested food) travels through Chyme ILEOCECAL VALVE to Large intestines/colon ILEOCECAL COLON COLON WASTE GOES BYE-BYE! WHAT NEXT? WHAT If the Colon Excretes What We Don’t If Need…..What Happens to What We DO Need? Need? ABSORPTION Key Factors for Absorption Key Need to Break Down Foods First Need Absorption Possible Key Players….. Hormones and Enzymes Some Keys to Absorption Some Hormones: • GASTRIN Location Stimulus Function Stomach Stomach Food Food secrete HCL secrete Secretin Sm Intestine Chyme stimulates stimulates pancreas to pancreas release bicarbonate bicarbonate CCK Sm Intestine FAT stimulates stimulates gall bladder gall to release BILE BILE Some Keys to Absorption Some Enzymes: Location Stimulus Function Amylase Mouth Starch Pepsidases Sm Intestine Protein break down break to amino acids to Proteases Stomach breaks pro down Lipase Sm Intestine Fat Protein break down break starch starch break down fat ABSORPTION ABSORPTION Where Does Absorption Occur? Mostly Sm and Lg Intestine How Do Nutrients Get Absorbed? Small Intestine Surface Folds Small Folds = Villi Villi Villi are covered with Microvilli Microvilli = hair-like structures hair-like These finger-like projections allow for the These collection of nutrients collection Absorption Absorption FOLDS Villi Villi Microvilli MICROVILLI MICROVILLI ABSORPTION ABSORPTION for water soluble nutrients... nutrient (digested if necessary) thru microvilli thru enters mucosal cell into capillaries into enters bloodstream via portal vein via passes thru liver into circulation circulation ABSORPTION ABSORPTION for most lipids, fat-soluble vitamins: for nutrient (digested if necessary) thru microvilli thru enters mucosal cell into lymph vessels into enters lymph system via thoracic duct via empties into circulation near heart Overview of Digestion and Absorption Absorption PLAY Overview of Digestion and Absorption ...
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