The Digestive System

 To identify and describe the major structures and functions of the digestive system  To describe the processes of digestion, absorption and metabolism  To recognize, define, pronounce, and spell terms related to the pathology and treatment of disorders related to the digestive system

 To intake and digest food  To absorb nutrients from food  To prepare and eliminate solid waste

The gastrointestinal tract is another term for the major organs of the digestive system  The upper GI tract includes the mouth (oral cavity), esophagus, and stomach  The lower GI tract includes the small and large intestines, rectum and anus The accessory organs aid with digestion but are not part o the GI Tract. These organs include the  liver  pancreas  gallbladder

The major structures of the oral cavity (mouth) are the lips, hard and soft palates, salivary glands, tongue, teeth and periodontium Digestion begins in the oral cavity

 The lips are also known as labia. The have important roles in breathing, speaking, expression of emotion and chewing (holding food in mouth and guiding food).  The tongue aids in speech, moves food for chewing and swallowing and contains the papillae (or taste buds).  The periodontium consists of the bony and soft tissue structures that surround and support the teeth. This includes the gingiva (gums).  Dentition refers to the natural teeth.  Primary (deciduous)dentition (baby teeth) = 20 teeth  Permanent dentition (adult teeth) =32 teeth  Edentulous means without teeth (loss of permanent teeth)  Mastication is the act of chewing.

 Saliva is a colorless liquid that moistens the mouth, begins digestion and lubricates food in the mouth.  There are 3 pairs of salivary glands  Parotid glands  Sublingual glands  Submandibular glands

 The pharynx (as discussed in unit 7) has three sections and allows air to pass to the respiratory system and food/liquid to enter the digestive system.  The epiglottis prevents food and liquid from entering the respiratory system upon swallowing.  The esophagus is the muscular tube that leads from the laryngopharynx to the stomach.

 Peristalsis (a series of wavelike contractions) by the smooth muscle of the digestive system moves food through the GI tract.  The churning motion in the stomach which combines the food with gastric acids turns the food into chyme.  Chyme is the semifluid mass of partly digested food that passes into the small intestine.  Absorption of nutrients occurs in the small intestine via the villi in the wall of the small intestine.  The small intestine is approximately 20 ft long. It is called the small intestine because its diameter is smaller than the large intestine.  The small intestine consists of three sections  Duodenem  Jejunum  Ileum

 The large intesine is about twice as wide as the small intestine but only ¼ as long.  Here waste products of digestion are processed in preparation for excretion.  There are four major sections of the large intestine 1. Cecum (the vermiform appendix, “appendix”, hangs of the end of the cecum. 2. Colon (has four parts of its own, the ascending colon, transverse colon, descending colon and sigmoid colon) 3. Rectum 4. Anus  Food waste enters the large intestine in liquid form. Excess water is reabsorbed into the body and turns the waste into feces (stools), which are solid body wastes.  Defecation refers to the removal of solid waste from the body. Also referred to as a bowel movement.  Bororygmus is the rumbling noise caused by gas moving in the intestine.  Flatulence is the passing of gas through the rectum.

 Liver  Removes excess glucose from the blood and stores it as glycogen.  Destroys old erythrocytes  Removes toxins from the blood  Manufactures some blood proteins including bile (aids in the digestion of fats)and bilirubin.  Gallbladder  Located under the liver (green in color)  Stores and concentrates bile for later use.  Pancreas  Plays a role in the digestive system and endocrine system  Located behind the stomach  Secretes pancreatic juices that aid in digestion  In the endocrine system, it produces and secretes insulin.

 Digestion is the process by which complex foods are broken down into nutrients in a form the body can use.  Nutrient is a substance, usually from food, that is necessary for normal functioning of the body. The six types of nutrients are carbohydrates, proteins, fats, vitamins, minerals and water.  Metabolism includes all the processes involved in the body’s use of nutrients. It is the sum of anabolism and catabolism  Anabolism is the building up of the body cells and tissues.  Catabolism is the breaking down of the body cells or tissues.  Absorption is the process by which nutrients are taken into the bloodstream to be used by the cells of the body.

 Bariatrics is concerned with the prevention and control of obesity  Dentist specializes in the care of the teeth and oral cavity  Gastroenterologist specializes in the care of the stomach and intestines.  Orthodontist is a dental professional who specializes in the alignment of the teeth.  Periodontist is a dental professional who specializes in the tissues surrounding the teeth.  Proctologist is a physician who specializes in the colon, rectum and anus.

 GERD (gastroesophageal reflux disease) upward flow of acid from the stomach itno the esophagus.  Pyrosis (heartburn)  Peptic ulcer: sores that affect the mucous membranes of the digestive system  Anorexia nervosa: eating disorder characterized by intense fear of gaining weight and refusal to maintain a normal body weight.  Bulimia nervosa : eating disorder characterized by frequent episodes of binging and purging.  Obesity: excessive accumulation of fat in the body. Generally more than 30% overweight.  Ileus: the partial or complete blockage of the intestines  IBS (irritable bowel syndrome) common condition of unknown cause with symptoms of cramping, pain, constipation and /or diarrhea.  IBD (inflammatory bowel disease) general term for disease that cause inflammation of the intestine  Cirrhosis is a progressive degeneration of the liver often caused by excessive alcohol consumption or hepatitis  There are 5 hepatitis viruses that are named A-E HAV, HBV, HCV, HDV, HEV YOU ARE ALSO RESPONSIBLE FOR TERMS MADE FROM YOUR WORD PARTS

 Hemoccult test looks for hidden blood in stools.  Nasogastric intubation is the placement of a feeding tube through the nose and into the stomach  Gastrostomy tube is a surgically placed feeding tube from the exterior of the body into the stomach  TPN total parenteral nutrition is administered to the patient via IV fluid. The nutrition does not enter the digestive system. YOU ARE ALSO RESPONSIBLE FOR TERMS MADE FROM YOUR WORD PARTS