Transcript File
Chapter 24 The Digestive and Urinary System Section 1 – The Digestive System • • • • • • • • • • Vocabulary Terms Digestive system – Esophagus – Stomach – Small Intestine – Pancreas – Liver – Gallbladder – Large Intestine – The Digestive system The Digestive System – A group of organs that work together to digest food so that it can be used by your body for energy. – The Digestive Tract – includes mouth, Throat, esophagus, stomach, small intestine, large intestine, rectum, and anus. Also your salivary glands, liver, gallbladder, pancreas are also part of the digestive system. Two forms of digestion a. Mechanical – breaking, crushing, and mashing of food b. Chemical – large molecules are broken down into nutrients – Nutrients – Three major types • Carbohydrates • Proteins • Fats • Enzymes – break nutrients into smaller molecules called amino acids Digestion Begins in the Mouth – You need to chew food so it is broken into smaller pieces, moistened and easier to swallow as well as digest. Teeth – – • • Layers – Enamel – hardest material in the body and the outermost layer of teeth Types of Teeth – – – – – • Molars – grind food Premolars – mashing food Incisors – shred food Canines – shredding food Food gets mixed with saliva which starts the process of digestion chemically. Stomach • Food goes down your esophagus using peristalsis (wave motion) to the stomach. In the stomach the food is squeezed – Your stomach produces enzymes and acid these break down food and kill any bacteria that may have been swallowed. • Your digested food is called chyme Small Intestine – Chyme enters the small intestine through a valve. Chyme is slowly released giving the small intestine time to mix the chyme with juices from the liver and pancreas. Most chemical digestion takes place the small intestine • Villi- Surface area is greater than a tennis court. This is because of villi. Villi are covered with tiny nutrient absorbing cells. These cells dump nutrients into the bloodstream. Pancreas, Liver, Gallbladder a. The Pancreas, Liver, and Gallbladder are linked to the small intestine but no food goes through them. b. Pancreas – Located between the stomach and he small intestine. Secretes juice into the small intestine. Bicarbonate is released which neutralizes the acid in chyme so it doesn’t eat the intestinal wall lining. The pancreas also helps the endocrine system by regulating blood sugar Pancreas, Liver, Gallbladder – The liver and Gallbladder – • Liver – located above the stomach but linked to the small intestine – makes bile (used in fat digestion) – Stores nutrients – Breaks down toxic substance in the blood (alcohol, drugs) – makes cholesterol for the cell membrane Pancreas, Liver, Gallbladder • Gallbladder – Stores bile from the liver before the bile enters the small intestine where it breaks up fat droplets The Digestive tract Cont. – Nutrients are absorbed into the bloodstream. If they are not needed right away then they are stored in the liver till they are needed.\ Large Intestine – Stores, compacts, eliminates indigestible materials – only called large because the diameter is bigger. – • Soupy mixture enters the large intestine where most of the water is reabsorbed. Fiber helps keep the stool soft and moving smoothly. Fiber is found in fruits, veggies, and whole grain The Digestive tract Cont. – Rectum – Stores feces (stool) till it can be expelled – Whole process takes about 24 hours Problems of the Digestive system – Most are related to what you eat but some are diseases. – Heartburn – When acidic chyme flows into the esophagus causing a burning sensation. Happens mostly when you eat too much, et right before bed, eat acidic foods – Constipation and diarrhea – When too much water is removed or too little water is removed. – Colon Cancer – cancer in the long tubular portion of the large intestine. Creates a tumor which can spread easily. – Gastric Ulcer – open sore in the stomach usually caused by bacteria Section 2 – the Urinary System • • • • • • Vocabulary terms Urinary System – Kidney – Nephron – Urine – Urinary Bladder – The Urinary System • One way that excretion takes place. The other two are through the skin and through the lungs. Excretion is only when a substance passes through a membrane in order to leave the body. – Your urinary system cleans your blood by removing all the wastes that are picked up from the cells. Kidneys – cleans the blood cycles about 350 times per day. – • Nephrons – microscopic filters in the kidneys How the Kidneys Filter blood • • • • • • • A large artery brings blood into each kidney. Tiny blood vessels branch off the main artery and pass through part of each nephron Water and other small substances, such as glucose, salts, amino acids, and urea, are forced out of the blood vessels and into the nephrons As these substances flow through the nephrons, most of the water and some nutrients are moved back into the blood vessels that wrap around the nephrons. A concentrated mixture of waste materials is left behind in the nephrons. The cleaned blood, now slightly less water and much less waste material, leaves each kidney in a large vein to recirculate in the body The yellow fluid that remains in the nephrons is called urine. Urine leaves each kidney through a slender tube called the ureter and flows into the urinary bladder, where it is stored. Urine leaves the body through another tube called the urethra. Urination is the process of expelling urine from the body. Your body must regulate water. • • • When you are hydrated enough your body stops making saliva which is why you feel thirsty Antidiuretic hormone – ADH signals kidneys to take water back from the nephrons and return it to the bloodstream, your kidneys then makes less urine. Caffeine is a diuretic which cause the kidneys to make more urine thereby taking more water out of the blood. So caffeine causes you to be more thirsty. Ailments – Bacterial infections – bacteria can spread throughout your urinary system – Kidney stones – salts and wastes collect inside the kidneys. This interferes with urine flow. Shockwaves can sometimes break stones up – Kidney Disease – damage to the nephrons can cause the kidney to stop filtering blood. Dialysis is where blood is taken from a artery and filtered by a machine then pumped back into your body.