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Topic 1:Nutrition Why is a healthy diet important? • How do we know how much energy is in a nutrient? • Calories: energy stored in food • How many calories should you eat a day? Active Teenagers: Males – 2,500 Calories Females- 2,200 Calories Calorie • A unit used to measure the energy content of food (nutrients). • More specifically, a calorie is defined as the amount of heat required to raise the temperature of 1 gram of water 1 degree Celsius. • The Calorie that is used on nutritional labels is actually 1000 of these scientific calories. • In general, the more calories a food product contains, the more energy it can release. A: The size of a single serving & the # of servings in the container. B: The total Calories in one serving of food & how many Calories from fat. C: mg & g of nutrients as well as the percentage of the Daily Value in one serving. D: Percentage Daily Value for Vitamins & minerals. E: Provides information on recommended daily nutrient intake for people who require 2,000 or 2,500 Calories per day. G: Lists the ingredients in the food, from the most abundant to the least. Nutrients • Substances in food that are needed for energy, growth and repair. ALL MUST BE • Carbohydrates PRESENT IN • Fats YOUR DIET ! • Proteins • Vitamins and Minerals • Water Food Pyramid Fats, oils, and sweets Milk, yogurt, and cheese Vegetables 60% 10% 30% Meat, poultry, and fish Fruits Bread and Grain Carbohydrates STORAGE • Main source of energy STORAGE BLOOD • Ex. Bread, pasta, potatoes, rice • Digested Carbs = glucose Fiber: found in fruits, vegetables and grains is a good source of ROUGHAGE. Fiber helps intestinal muscles to keep food and wastes moving along. LIVER Fats (Lipids) • Energy Source FAT • Provides the most energy per gram • Needed for cell membranes, nervous system, insulation, and cushions organs. • Types: Saturated & Unsaturated. Proteins • Digested into amino acids. • Used to make hormones and enzymes. Proteins can also be used build and repair body parts. • Ex. Meat, eggs, beans, nuts. Vitamins and Minerals • Nutrients the body needs in SMALL amounts. Vitamins Vitamin D that aid in chemical reactions • Organic molecules Coenzymes • Ex: Vitamin A and Vitamin D Minerals • Inorganic substances required for the body to function normally. Ex: Iron and calcium hemoglobin Water • The most important of all nutrients • Why is water the most important nutrient when it has NO nutritional value and provides NO energy? • Because all of the body processes and chemical reactions take place in water. Over half of your body weight is water. Women 50% Men 60% Topic: Digestive System Alimentary Canal – the “tube” digestion takes place in. 1. Four Stages of Food Processing: Ingestion – the act of eating or drinking. Digestion – the process of breaking food down into molecules small enough for the body to absorb. Absorption – certain cells take up (absorb) the small molecules. Elimination – undigested material passes out of the body. 2. Digestion • The process by which food products are broken down. • Types: MECHANICAL: CHEMICAL: The physical breakdown Enzymes breakdown food of food into smaller into smaller pieces (Ex: pieces (Ex: chewing) amino acids) Chemical Digestion: Enzymes play a critical role in the digestion (hydrolysis) of nutrients. 3a. Mouth: • Intake of food through the mouth! • Both mechanically (teeth and tongue) and chemically (salivary amylase – an enzyme that breaks down starch) digestion occurs.) • Then the food mixes with saliva and travels down through the esophagus. 3b. Esophagus Long muscular tube that connects the stomach to the pharynx (upper portion of the throat). No Digestion takes place here! Peristalsis • Process by which muscular contractions move food through the esophagus to the stomach. 3c. Stomach • Both mechanically (churning) and chemically (pepsin) digestion occur. Gastric Juice Stomach Glands Enzyme specificity HCL (Hydrochloric Acid) Pepsin Acidic pH Digestion of proteins Kill Bacteria Which stomach will work? 1 = water 3 = water + acid 2 = water + pepsin 4 = acid + pepsin What is the optimum pH and temperature for pepsin? Optimum pH = 2 Optimum Temp = 40 3d. Small Intestine •Most digestion takes place and is completed here chemically. •Enzymes: Amylase Digests Starch Trypsin Lipase Digests Proteins Digests Lipids Small Intestine • Responsible for digestion and absorption of nutrients. • The enzymes (amylase, trypsin, and lipase) are produced by accessory organs. Accessory Organs No Food Passes Through Them 1. Liver – makes bile 2. Gallbladder – stores and releases bile into S.I. 3. Pancreas – makes and releases (pancrfeatic juice) amylase, trypsin, and lipase into S.I. Bile -Emulsifies fats -Breaks into smaller droplets (mechanical digestion) -Increases surface area of fats Absorption The Small Intestine is ideal for absorption because: -Its very long (about 21 feet) -Many folds -Has villi (finger like projections) Villi Blood Vessels Carry Nutrients away from the digestive system to the parts of the body that require them. Nutrients diffuse Into the bloodstream! 3f. Large Intestine • Undigested material passes into the L.I • No digestion occurs here • The major function is to reabsorb water & vitamins. • Stores waste (feces) in the rectum. • Elimination through the anus. What is the major role of the Digestive System (How does it help us maintain homeostasis? The digestive system is responsible for breaking down nutrients into smaller components so they can enter our bloodstream & be delivered to our cells & can diffuse across the cell membrane. Polysaccharides Monosaccharides Proteins Amino Acids Lipids Fatty Acids & Glycerlol Diffusion Cell It's a Gas Scientists estimate that the average adult releases between 12 and 122 cubic inches of intestinal gas each day. Most of that gas is made up of hydrogen and methane produced by the bacteria as they ferment the fiber that was not digested in the stomach or small intestine. Many fruits and vegetables, especially beans, contain these polysaccharides, which cannot be broken down by the enzymes in the stomach or small intestine. As the bacteria decompose these complex sugars, gas is released. Most of the gas is passed without notice. Common wisdom tells us that beans give us a lot of gas—more than could pass without notice. Ever questing for eternal answers, scientists in one study measured the intestinal gas produced by people who ate a control diet and compared them to those who ate a meal that was half pork and beans. The folks in the control group released .9 cubic inches per hour of flatus (intestinal gas) while the pork and beans group released a whopping 10.7 cubic inches. Weird Science Fact Alexis St. Martin, a French Canadian, was accidentally wounded by a short gun blast in 1822. Fortunately, Dr. William Beaumont, an army surgeon, was nearby and began treatment of the wound immediately. St. Martin’s recuperation lasted nearly three years, and the enormous wound healed except for a small opening leading into his stomach. A fold of flesh covered this opening; when this was pushed aside the interior of the stomach was exposed to view. Dr. Beaumont began a series of experiments and observations that formed the basis of our modern knowledge of digestion. Topic: How can the digestive system malfunction? Types • Heartburn • Ulcers • Diarrhea • Constipation • Appendicitis • Gallstones 1. Heartburn Acid from the stomach backs up into the esophagus Treatment: Antacids 2. Ulcer Lining of the digestive tract becomes irritated and erodes. Causes: H. pylori bacteria, stress, smoking, and some medications. Treatment: change diet, acid reducing drugs, antibiotics 3. Constipation • Too much water is removed by the Large intestines • Feces egested infrequently and with difficulty. • Treatment: medication and fiber. 4. Diarrhea Not enough water is absorbed by the Large intestines Feces are watery and frequent Can cause dehydration Treatment: Medications 5. Appendicitis Appendix becomes inflamed due to infection Treatment: surgery & antibiotics 6. Gallstones Small deposits of cholesterol form hard stones that become trapped in the gallbladder Treatment: removal of gallbladder or the stones. Topic: How does excretion in humans remove harmful wastes? Your Body’s Filter Have you ever seen a water-purification system attached to a faucet? This system removes impurities from the water such as arsenic or other chemicals that can be harmful to people. As water passes through the filters contained in the system, the impurities are trapped on the surface of the filters. Eventually, the water that comes out of this purifier is free of the impurities. 1. Your body has its own system for filtering blood. Why might the blood in your body need to be filtered? 2. What organs do you think filter your blood? 3. How do you think the filtered materials leave your body? 1. Urinary System • Blood in the artery enters the kidney • In the kidney the blood gets cleaned of metabolic waste • The vein carries clean blood back to the heart • The ureter carries urine to bladder • The bladder is where urine is stored • When the bladder is full, it sends a message to the brain • The urine (water, urea, & other wastes) exits the body through the urethra. 2. Kidneys: How do they maintain homeostasis? • The primary organs in excretion, play a vital role in maintaining the homeostasis of body fluids. They excrete waste products & regulate water & salt balance in the blood. 3. Nephron Made of millions of nephrons which filter the blood of SALT, WATER, and UREA. Nephron 4. Parts of the Nephron: 1)Glomerulus – tiny ball of capillaries located at the beginning of each nephron tubule. 2) Bowman’s Capsule – cupshaped portion of the nephron that surrounds the glomerulus. Nephron 5. Blood Processing: 1)Filtration – blood pressure forces fluid (water, urea, glucose, amino acids) from the glomerulus into the Bowman’s Capsule (not proteins). 2)Reabsorption – water and dissolved nutrients, such as glucose, salts, & amino acids, are reabsorbed back into the blood. Nephron Blood Processing: 3)Secretion – kidneys remove certain substances from the blood and add them to the filtrate. 4)Excretion – now the filtrate is called urine and will be sent to the ureter, the bladder, & then the urethra to be excreted from the body. 6. Other Excretory Organs •Liver •Lungs •Skin a. LIVER •Destroys old RBCs •Produces urea from breaking down amino acids (ammonia to urea) •Stores glycogen •Detoxifies many harmful substances b. Lungs •Get rid of :____ & _____ c. Skin (Integumentary) • Gets rid of extra heat • Gets rid of water and salt • Has 2 to 5 million sweat glands Sweat Gland 7. How does our excretory system help maintain homeostasis? •Temperature balance •Water balance •Waste balance •Gas balance Topic: How can the excretory system malfunction? Kidneys • The primary excretory organ. It plays a vital role in maintaining the homeostasis of body fluids. They control the amount of ammonia, salt, and water in the blood. How does our excretory system help maintain homeostasis? •Temperature balance •Water balance •Waste balance •Gas balance 1. What are some metabolic wastes? •Urea – from protein breakdown •Salts •Water – from cell respiration •CO2 – from cell respiration Homeostasis: Water Level in Blood Water in Blood ADH Reabsorption of Water Water in Blood ADH Reabsorption of Water 2. Diabetes Insipidus Symptoms: Excretion of large amounts of watery urine Unquenchable thirst Causes: Kidney is not reabsorbing water back into the bloodstream Treatment: Desmopressin – causes the kidney to reabsorb more water. 3. Kidney Stones • Urine becomes too concentrated and crystallizes forming small jagged stones. • The stones can clog and block urine passage through the kidneys. • Certain foods (like carbonated beverages) have been linked to their formation. Who gets kidney stones? • For unknown reasons, the number of people in the United States with kidney stones has been increasing over the past 20 years. • White Americans are more prone to develop kidney stones than African Americans. • Stones occur more frequently in men. • Kidney stones strike most typically between the ages of 20 and 40. • Once a person gets more than one stone, others are likely to develop. 4. Kidney Failure Dialysis • The main function of the kidney is to balance fluid in the body. • Dialysis filters the blood for individuals who have nonfunctioning kidneys. • Excess fluid in the blood can cause high blood pressure and may eventually contribute to heart disease. 5. Dialysis Dialysis treatments take about 4 hours, and most dialysis patients require three treatments a week. 6. Kidney Transplant • The success rate for kidney transplants is excellent and higher than for other kinds of organ transplants. • A person can live with only ONE kidney