3 Functions of the Digestive System DigestionThe mechanical and chemical breakdown of foods for use by the body’s cellsAbsorptionThe passage of digested food from the digestive tract into the cardiovascular systemEliminationThe expulsion of undigested food or body wastes
4 Functions of the Digestive System Digestion involves both mechanical and chemical processesMechanical- chewing, mashing, and breaking food into smaller pieces.Chemical- Digestive juices change the food into simpler substances.The nervous system triggers the digestive process to begin at the sight or smell of food and controls muscles involved with digestion.The cardiovascular system moves the nutrients to the cells of the body.
5 Ingestion Ingestion is the process of taking food into the body, 3 Primary Structures involved:Teeth- Breaks the food into smaller pieces by chewing, or mastication, which prepares food to be swallowed.Salivary glands- Produces saliva which aids in breakdown of starches and sugars in food. It also helps lubricate food, making it easier to swallow.Tongue- Forms chewed food into size and shape that can be swallowed.
6 SwallowingAs you swallow, muscular contractions force food into the throat (pharynx).The Uvula, which is a small flap in the back of the throat closes the nasal passage.The epiglottis, another small flap, closes the opening to the trachea (windpipe) to prevent food from entering the respiratory system.
7 The EsophagusWhen food is swallowed, it moves into the esophagus, which is a muscular tube that extends about 10 inches from the pharynx to the stomach.Food moves through the esophagus, stomach, and intestines through a series of rhythmic, wavelike muscular contractions called peristalsis.The esophageal sphincter sits at the junction of the stomach and esophagus and allows food to enter the stomach.
8 The StomachThe stomach is a hollow, saclike organ that is enclosed in a muscular wall. These muscles allow the stomach to expand when you eat.The Stomach has 3 tasks in digestion:Mixing foods with gastric juicesGastric juices are secretions from the stomach lining that contain acid and peptin, which helps break down protein. Mucus in the stomach lining prevent the strong acids from digesting the stomach.Storing swallowed food and fluidsThe stomach holds food and liquid for further digestion before they move into the small intestineMoving food into the small intestineAs food is digested, it is converted to chyme, which is a creamy, fluid mixture of food and gastric juices.
9 The Pancreas, Liver, & Gallbladder Pancreas- Produces enzymes that break down fats, carbohydrates, and proteins in food.Liver- Produces bile, a yellow-green, bitter fluid important in the breakdown and absorption of fats.Gallbladder- Stores bile in times between meals.These fluids mix with other digestive juices and chyme in the small intestine.
10 The Small IntestineAbout feet in length and 1 inch in diameter.The inner wall of the small intestine contains millions of fingerlike projections called villi.These villi contain capillaries that collect nutrients and carry them throughout the body through the cardiovascular system.Undigested material leaves the small intestine and enters the large intestine through peristalsis.
11 The Large IntestineThe large intestine is about 5 to 6 feet in length and about 2.5 inches in diameter.It’s main functions are to absorb water, vitamins, and salts, and to eliminate wastes.
12 Removing Wastes From the Body The body produces wastes in the forms of solids, liquids, and gasses.Solid wastes are removed through the large intestine where bacteria convert the undigested food materials into a semisolid mass called feces. Feces are excreted through the anus during a bowel movement.The skin excretes some wastes through the pores by perspiration.The lungs expel carbon dioxide, a gaseous waste when you breathe.Liquid wastes are filtered through the urinary system.
13 Care and Problems of the Digestive System Lesson 2
14 Health Behaviors and the Digestive System These behaviors will help lead to a lifetime free of digestive problems:Eat a well balanced dietWash your hands before and after preparing foodEat slowly and chew your food thoroughlyDrink at least 8 8oz. Glasses of water dailyAvoid using food as a way of dealing with stress and emotion
15 Problems of the Digestive System Can range from minor discomfort caused by gas or indigestion to more serious problems that need immediate medical attention such as appendicitisProblems can either be Functional or Structural
16 Functional Problems of the Digestive System IndigestionFeeling of discomfort in the upper abdomen.Can be accompanied by gas and nauseaCan be caused by eating too much, eating too quickly, & spicy foods that are high in fat.Stomach orders and stress can lead to indigestionHeartburnBurning sensation in the center of the chest that may rise from the tip of the breastbone up to the throat.Results from acid reflux, or backflow of stomach acid into the esophagus.As acid enters the esophagus, it irritates the tissues, causing a burning sensation
17 Functional Problems of the Digestive System Hiatal HerniaCondition in which part of the stomach pushes through an opening in the diaphragm.Persistent heartburn can be a symptom of hiatal hernia.GasCertain amounts of gas are considered normal.Excessive gas can result in cramps or uncomfortable feelings of fullness.Certain foods may cause excess gas in some people, but not in others.ConstipationCondition in which feces become dry and hard and bowel movements become difficult.Can be caused by not getting enough fiber or water.
18 Functional Problems of the Digestive System NauseaFeeling of discomfort that sometimes precedes vomiting.Caused by motion sickness, pathogens, some medications, and dehydration.Vomiting is a reflex in which the contents of the stomach are brought back up the esophagus and out of the mouth. This is caused by powerful muscular contractions in the stomach.DiarrheaFrequent passage of watery feces.Occurs when digested food passes too quickly through the large intestineCan be cause by changes in eating style, overeating, pathogens, or nutritional deficiencies.Large concern is dehydration.
19 Structural Problems of the Digestive System GallstonesFormed when cholesterol in bile crystalizes and blocks the bile duct between the small intestine and gallbladder.Symptoms include pain, nausea, vomiting, and feverCan be treated with medication, ultrasound or surgery.AppendicitisInflammation of the appendixSymptoms include pain, fever, loss of appetite, nausea, vomiting, and tenderness in the area.Can be a very serious problem if the appendix burstsTreatment includes surgical removal of the appendix.
20 Structural Problems of the Digestive System GastritisInflammation of the mucus membrane that lines the stomach.Caused by use of tobacco or alcohol, infection, and certain medications (aspirin)Symptoms include pain, indigestion, decreased appetite, & nausea and vomiting.Lactose IntoleranceCause by underproduction of enzyme Lactase, which aids in breaking down dairy products.Bacteria in the small intestine ferment and cause symptoms of abdominal cramps, bloating , gas, and diarrhea.People with lactose intolerance should avoid dairy products and switch to alternate sources of calcium.
21 Structural Problems of the Digestive System Peptic UlcerA sore in the lining of the digestive tractCan be caused by regular use of medications (aspirin), or by infectionSymptoms include nausea, vomiting, and abdominal pain that worsens when the stomach is empty.CirrhosisDestruction of liver tissue, usually caused by prolonged and heavy alcohol use.Can lead to total liver failure and death unless a liver transplant is performed.Crohn’s DiseaseCauses inflammation of the linin of the digestive tract.Symptoms include diarrhea, weight loss, fever, and abdominal pain.No known cause but has been thought to have stemmed from immune disorders
22 Structural Problems of the Digestive System Colon CancerSecond leading cause of cancer deaths in the United StatesUsually develops in the rectum and blocks the colon or causes bleeding with elimination.Slow spreading- early medical help yields much higher survival rates.ColitisInflammation of large intestine or colonMay be caused by bacterial or viral infectionSymptoms include fever, abdominal pain, and diarrhea that may contain bloodHemorrhoidsVeins in the rectum and anus that are swollen as a result of increased pressure.May occur with constipation, during pregnancy, and after childbirthSymptoms include itching, pain, and bleeding
24 Function of the Urinary System Main function is to filter waste and extra fluid from the body.Urine is liquid waste material excreted from the body through the process of urination.Urine consists of water and body wastes that contain nitrogen.These wastes become toxic to the cells if they remain in the body for too long.
25 The KidneysBean shaped organs that are about the size of a fist near the middle of the back, just below the rib cage.Remove waste products from the blood through tiny filtering units called nephrons.Each kidney contains millions of nephrons.Each nephrons contains a small ball of capillaries called a glomerulus and a small tube called a renal tubule that functions as a filtering funnel.As part of the filtering process, the kidneys adjust the amount of salt, water, and other materials excreted in the urine according to the body’s needs.They monitor and maintain the body’s acid-base and water balances.
26 The UretersThe ureters are tubes that connect the kidneys to the bladder.Each ureter is about 8-10 inches longMuscles in the ureter walls tighten and relax to force urine down and away from the kidneysSome amount of urine is passed from the ureters and the bladder every 15 seconds.
27 The Bladder and the Urethra The bladder is a hollow muscular organ that acts as a reservoir for urine.Located in the pelvic cavity, the bladder is held in place by ligaments attached to other organs and the pelvic bones.Until the bladder is ready to be emptied, sphincter muscles close tightly around the opening into the urethra.The urethra is the tube that leads from the bladder to the outside of the body
28 Healthy Behaviors and the Urinary System Drink at least 8 8oz. Glasses of water each dayLimit the amount of caffeine and soft drinks as they can lead to dehydrationEat a well balanced dietPractice good hygiene and personal health to avoid bacterial infectionHave regular medical check-ups.Report any changes in color, odor, or frequency of urine elimination to a doctor as they can be warning signs of urinary system disorders
29 Problems of the Urinary System Can result from several different conditions, including infection or blockage of urine.Cystitis is an inflammation of the bladder, most often caused by bacterial infection, which can spread to the kidneysUrethritis is the inflammation of the urethra that can be caused by a bacterial infection.Symptoms of both can include burning pain during urination, increase frequency of urination, fever, and the presence of blood in the urine.
30 Kidney Problems Nephritis Kidney Stones Uremia Inflammation of the nephrons. Symptoms include fever, tissue swelling, and changes in urine productionKidney StonesForm when salts in the urine crystallize into stones. Small stones can normally pass naturally but larger ones my need ultrasound treatment in order to break them into small pieces.UremiaAssociated with decreased blood filtration by the kidneys. Leads to abnormally high concentrations of nitrogen which can cause tissue damage.
31 Kidney FailureCan be acute or chronic. Treatment includes reducing symptoms and slowing progression.HemodialysisTechnique in which an artificial kidney machine removes waste products from the blood.Peritoneal dialysisUses a thin membrane that surrounds the digestive organs to filter blood.Kidney transplantInvolves replacing non-functional kidney with healthy kidney from a donor.