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Notes Would you like to save points on you next test? Take notes! Digestive System and Excretory System 7th Grade Biology The Nutrients But First… Nutrients The Nutrients Nutrients Fuels Building Blocks Used for Movement, Growth and Repair The Nutrients Nutrients 6 Types Carbohydrates (Sugars and Starches) Proteins (made from amino acids) Fats Vitamins Minerals (from the Earth) Water The Nutrients Nutrients The Nutrients Nutrients The Nutrients Nutrients Nutrients enter the body where the digestive and circulatory systems interact. The Digestive System In Humans and other Mammals, the Digestive System consists of the mouth, teeth, saliva glands, esophagus, stomach, small and large intestines, aided by the liver, gallbladder and pancreas. This system converts food into energy and breaks down the non-nutritive components into waste to be excreted. The Digestive System The Digestive System also interacts with the Nervous System. The digestive System Mouth • Food comes in this way and digestion starts here! The digestive System Mouth • Food comes in this way and digestion starts here! The digestive System Teeth There should be about 32 teeth in the adult mouth. Teeth help you chop your food, breaking it down and increasing the surface area. The digestive System Saliva Glands When you do eat, the saliva breaks down the chemicals in the food a bit and helps make the food mushy and easy to swallow. Saliva contains enzymes. The digestive System Saliva You produce about 1.5 liters of saliva per day The digestive System Tongue Your tongue helps out, pushing the food around while you chew with your teeth. It mixes in saliva. When you're ready to swallow, the tongue pushes a tiny bit of mushed-up food called a bolus toward the back of your throat and into the opening of your esophagus, the second part of the digestive tract. The digestive System Mastication The digestive System Esophagus The passageway to the stomach is about 10 inches long (25 cm) Food moves down the esophagus with a wave like motion called peristalsis The digestive System Peristalsis Peristalsis is the rhythmic contraction of smooth muscles to propel contents through the digestive tract. The word is derived from New Latin and comes from the Greek peristaltikos, peristaltic, from peristellein, "to wrap around," and stellein, "to place." The digestive System Stomach The digestive System Stomach The stomach is lined with a protective mucus to protect it from itself! The stomach contains gastric juices that aid in the breaking down of food. The stomach also churns food to help mix in the acids break it down. The digestive System Stomach The digestive System Stomach The digestive System Juices! The digestive System But not these kinds of Juices The digestive System Gastric Juices The stomach contains both digestive enzymes and acids that work together and aid in the breaking down of food. Acid (HCL) Enzymes The digestive System Chyme Chyme is the semifluid mass of partly digested food expelled by the stomach into the duodenum. In other words, chyme is partially-digested food. The digestive System Small Intestine The small intestine breaks down the food mixture even more so your body can absorb all the vitamins, minerals, proteins, carbohydrates, and fats. The pepperoni on your pizza is full of proteins - and a little fat - and the small intestine can help extract them - with a little help from three friends: the pancreas, liver, and gallbladder. The digestive System Small Intestine The digestive System Small Intestine The S.I. is made of 3 main parts 1.Duodenum 26 cm (9.84 in) 2.Jejunum 2.5 m (8.2 ft) 3.ileum 3.5 m (11.5 ft) The digestive System Duodenum (First segment of the small intestine) The duodenum is a hollow jointed tube about 25-30 cm long connecting the stomach to the jejunum. It is the first and shortest part of the small intestine and it is where most chemical digestion takes place. The name duodenum is from the Latin duodenum digitorum, twelve fingers' breadths. The digestive System Liver •The liver is the largest organ inside the body weighing approximately 1500 grams, or 3-4 pounds. •Despite its large size it is hidden beneath your rib cage on the right hand side of your body. • Normally the liver remains hidden and is your silent partner. Perhaps this is why its function is so mysterious and unknown to many. •Liver function is very complex The digestive System Liver •The liver both stores and releases glucose, an essential sugar and source of energy required to maintain body functions. This is particularly important during periods of fasting, for example during sleep when the liver releases glucose which is vital for brain metabolism. •The liver is the primary source for the synthesis of proteins, particularly for proteins circulating in the blood, such as albumin and many of the clotting factors necessary to prevent bleeding into tissues. •The liver makes bile that is used to aid in digestion. The digestive System Liver The digestive System Gallbladder The gallbladder is an organ that is located on the underside of the liver and on the right side of the abdomen. The function of the gallbladder is to store bile that is produced in the liver before the bile is secreted into the intestines. Bile secreted into the intestines helps the body digest fats. The digestive System Gallbladder The digestive System Bile Duct Bile ducts are tubes that carry bile from the liver to the gallbladder for storage and to the small intestine to aid in digestion. The digestive System Bile Bile is a fluid produced by the liver that aids in the digestion process. The digestive System Pancreas The Pancreas is a gland organ in the Digestive System. It is both exocrine (secreting pancreatic juice containing digestive enzymes) and endocrine (producing several important hormones, including insulin, glucagon, and somatostatin). The digestive System Jejunum (Second segment of the small intestine) The jejunum is the central of the three divisions of the small intestine and lies between the duodenum and the ileum. In adult humans the jejunum is about 8ft long (2.5m). The pH in the jejunum is usually between 7 and 8 (neutral or slightly alkaline). The jejunum and the ileum are suspended which gives the bowel great mobility within the abdomen. It also contains muscles to help move the food along. The digestive System Jejunum (Second segment of the small intestine) The digestive System Jejunum (Second segment of the small intestine) The digestive System Ileum (Third and last segment of the small intestine) The ileum is the final section of the small intestine. It is about 6 to 12 feet (2-4 m) long in humans, follows the duodenum and jejunum. The pH in the ileum is usually between 7 and 8 (neutral or slightly alkaline). Its function is mainly to absorb vitamin B12 and bile salts and whatever products of digestion that were not absorbed by the jejunum The digestive System Large Intestine / Colon The large intestine, an organ which is now more commonly referred to by its Greek name, the colon, is the last part of the digestive system. Its function is to absorb the remaining water from indigestible food matter, store this unusable food matter (wastes) and then eliminate the wastes from the body. The digestive System Large Intestine / Colon The large intestine takes 12 to 25 hours to finish up the remaining processes of the digestive system. Food is not broken down any further in this stage of digestion. The large intestine absorbs vitamins that are created by the bacteria inhabiting the colon. It is also very important in compacting the feces. The digestive System Large Intestine / Colon Ascending Colon Transverse Colon Descending Colon Sigmoid Colon Rectum The digestive System Appendix The Excretory System The excretory system is the system that discharges wastes. It is responsible for the elimination of wastes produced by homeostasis. There are several parts of the body that are responsible for this process, such as the sweat glands, the liver, the lungs, and the kidney system. It removes wastes of the organism, balancing and regulating the chemical composition of its body fluids. The excretory system eliminates excretory products from the body, collects water and filters body fluids. Without the excretory system, the build-up of harmful wastes could damage the body, resulting in destructive, dangerous, and even fatal deadness. The Excretory System The Excretory System Urinary system Kidneys Nephron Urine Rectum / (sometimes the L.I. is considered part too) Lung Exhales Carbon dioxide Skin Sweats Liver Makes Bile Spleen Removes old RBCs The Excretory System Rectum The rectum (from the Latin rectum intestinum, meaning straight intestine) The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long. The rectum acts as a temporary storage facility for feces. As the rectal walls expand due to the materials filling it from within, stretch receptors from the nervous system located in the rectal walls stimulate the desire to defecate. If the urge is not acted upon, the material in the rectum is often returned to the colon where more water is absorbed. The Excretory System Anus In anatomy, the anus (from Latin ānus "ring (circle), anus") is the external opening of the rectum. Closure is controlled by sphincter muscles. Feces are expelled from the body through the anus during the act of defecation, which is the primary function of the anus. Most animals — from simple worms to elephants and humans — have a tubular gut, with a mouth at one end and an anus at the other. The Excretory System Anus The Excretory System Defecate The Excretory System Feces The Excretory System Urinary System The Excretory System Kidneys The kidneys are complex organs that have numerous biological roles. Their primary role is to maintain the homeostatic balance of bodily fluids by filtering and secreting metabolites (such as urea) and minerals from the blood and excreting them, along with water, as urine. Because the kidneys are poised to sense plasma concentrations of compounds such as sodium, potassium, hydrogen ion, oxygen, and glucose, they are important regulators of blood pressure, glucose metabolism, and erythropoeisis. The Excretory System Kidneys The medical field that studies the kidneys and diseases of the kidney is called nephrology. The prefix nephro- meaning kidney is from the Ancient Greek word nephros (νεφρός); the adjective renal meaning related to the kidney is from Latin rēnēs, meaning kidneys. The Excretory System Kidneys The Excretory System Ureter The Ureter is the tube that leads from the kidneys to the bladder. The Excretory System Bladder The important part of the excretory system stores Urine until it is excreted. The Excretory System Urethra The Urethra is the tube that leads from the bladder to the exit point for the urinary system. The Excretory System Urinate Did you take notes?
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