Digestive System PDF

The Structure of the digestive System The digestive system consists primarily of the gastrointestinal tract, which is also known as the GI tract (gastr/o means stomach, intestin means intestine, and -al means pertaining to). These organs work in cooperation with accessory organs It consists...

The Structure of the digestive System The digestive system consists primarily of the gastrointestinal tract, which is also known as the GI tract (gastr/o means stomach, intestin means intestine, and -al means pertaining to). These organs work in cooperation with accessory organs It consists of three parts: ✓ Upper GI tract ✓ Lower GI tract ✓ The accessory organs The Primary Strucure of the GI Tract The upper GI Tract: which consists of: ✓ The oral cavity (mouth). ✓ Pharynx (throat). ✓ Esophagus. ✓ Stomach. This transports food from the entry into the body until digestion begins in the stomach. The Secondary Structre of the Upper GI Tract The Oral Cavity (Mouth): The Lips: ✓ Surround the opening to the oral cavity. ✓During eating, the lips, tongue, and cheeks hold the food in the mouth. ✓The lips also have important roles in breathing, speaking, and the expression of emotions. The Palate: Which forms the roof of the mouth, consists of three major parts. ✓ The hard palate: is the anterior portion of the palate. ✓The soft palate: is the flexible posterior portion of the palate, during swallowing, it has the important role of closing off the nasal passage to prevent food and liquid from moving upward into the nasal cavity. ✓The uvula: is the third part, and it hangs from the free edge of the soft palate, during swallowing, it moves upward with the soft palate, it also plays an important role in snoring and in the formation of some speech sounds. The Tongue: The tongue is very strong, flexible, and muscular. The posterior portion of the tongue is attached. The anterior end of the tongue moves freely and is flexible. It is the structure of the tongue that makes it so important for chewing, speaking, and swallowing. The DentalArches & the Teeth The dental arches are the bony structures of the oral cavity. These arches hold the teeth firmly in position to facilitate chewing and speaking. The term dentition refers to the natural teeth arranged in the upper and lower jaws. The permanent dentition consists of 32 teeth designed to last a lifetime. Soft Tissues of the Oral Cavity The gingiva: also known as masticatory mucosa or the gums, is the specialized mucous membrane that covers the bone of the dental arches and surrounds the neck of the teeth (plural gingivae). Saliva and Salivary Glands Saliva is a colorless liquid that maintains the moisture in the mouth. It helps maintain the health of the teeth, and it begins the digestive process by lubricating food during chewing and swallowing. Upper GI Tract Organs Functions ✓ The Mouth: Begins preparation of food for digestion. ✓ The Pharynx: Transports food from the mouth to the esophagus. ✓ The Esophagus: Transports food from the pharynx to the stomach. ✓ The Stomach: Breaks down food and mixes it with gastric juices. The Pharynx Which is the common passage- way for both respiration and digestion. The pharynx plays an important role in swallowing. The epiglottis is a lid-like structure that closes off the entrance to the trachea to prevent food and liquids from moving from the pharynx during swallowing. The Esophagus Is the muscular tube through which ingested food passes from the pharynx to the stomach. The Stomach Gastric juices aid in the beginning of food digestion. Mucus produced by glands in the stomach create a protective coating on the lining of the stomach  The Lower GI Tract: which is sometimes referred to as the bowels, is made up of: ✓ The small and large intestines ✓ The rectum and anus. Here digestion is completed, and waste material is prepared for expulsion from the body. The Small Intestine The small intestine extends from the muscle at the base of the stomach to the first part of the large intestine. The Large Intestine The large intestine extends from the end of the small intestine to the anus. It is about twice as wide as the small intestine; however, it is only one-fourth as long. It is here that the waste products of digestion are processed in preparation for excretion through the anus. The major parts of the large intestine are the cecum, colon, rectum, and anus. Lower GI Tract Organs Functions.. ✓ The Small Intestine: Mixes chyme coming from the stomach with digestive juices to complete the digestion and absorption of most nutrients. ✓ The Large Intestine: Absorbs excess water, and prepares solid waste for elimination. ✓ The Rectum &Anus: Control the excretion of solid waste. The Accessory Organs Functions TheAccessory Organs which consist of : the liver , gallbladder & pancreas ✓ The Liver: Secretes bile and enzymes to aid in the digestion of fats. ✓ The Gallbladder: Stores bile, and releases it into the small intestine as needed. ✓ The Pancreas: Secretes digestive juices and enzymes into the small intestine as needed. The Accessory Organs of the Digestive System The liver Is the largest organ in the body. It has several important functions related to removing toxins from the blood and turning food into the fuel and nutrients the body needs. The term hepatic means pertaining to the liver (hepat means liver, and -ic means pertaining to). Bilirubin is a yellow to green fluid, commonly known as bile, that is manufactured by the liver and is necessary for the digestion of fat.  Excessive amounts of bilirubin in the body can lead to jaundice and other diseases. Bile, which aids in the digestion of fats, is a digestive juice secreted by the liver. Bile travels from the liver to the gallbladder, where it is concentrated and stored. The Gallbladder The gallbladder is a pear-shaped organ about the size of an egg located under the liver. It stores and concentrates bile for later use. The term cholecystic, means per- taining to the gallbladder (cholecyst means gallblad- der, and -ic means pertaining to). The pancreas Is a soft, 6-inch long oblong gland that is located behind the stomach. This gland has important roles in both the digestive and endocrine systems. The pancreas produces and secretes pancreatic juices that aid in digestion and contain digestive enzymes and sodium bicarbonate to help neutralize stomach acids. Pancreatic means pertaining to the pancreas. Vocabulary/Terms Related to the Digestive System Digestion Is the process by which complex foods are bro- ken down into nutrients in a form the body can use. The flow of food through the digestive system. Digestive enzymes are responsible for the chemical changes that break foods down into simpler forms of nutrients for use by the body. Anutrient Is a substance, usually from food, that is necessary for normal functioning of the body. The primary nutrients are carbohydrates, fats, and pro- teins. Vitamins and minerals are essential nutrients, which are required only in small amounts. Metabolism The term metabolism includes all of the processes involved in the body’s use of nutrients (metabol means change, and -ism means condition),it consists of two parts: anabolism and catabolism. Anabolism Is the building up of body cells and substances from nutrients.Anabolism is the opposite of catabolism. Catabolism Is the breaking down of body cells or substances, releasing energy and carbon dioxide. Absorption Is the process by which completely digested nutrients are transported to the cells throughout the body. Peptic Ulcers Are sores that affect the mucous membranes of the digestive system (pept means digestion, and -ic means pertaining to). Anorexia Is the loss of appetite for food, especially when caused by disease. Dehydration Is a condition in which fluid loss exceeds fluid intake and disrupts the body’s normal electrolyte balance (de- means removal, hydra means water, and -tion means the process of). Malnutrition Is a lack of proper food or nutrients in the body due to a shortage of food, poor eating habits, or the inability of the body to digest, absorb, and dis- tribute these nutrients. Mal- is a prefix meaning bad or poor. Malabsorption Is a condition in which the small intestine cannot absorb nutrients from food that passes through it. Obesity Is an excessive accumulation of fat in the body. The term obese is usually used to refer to individuals who are more than 20 to 30% over the established weight standards for their height, age, and gender. The body mass index (BMI) Is a number that shows body weight adjusted for height. The results fall into one of these categories: underweight, normal, over- weight, or obese. Nausea Is the urge to vomit. Intestinal Obstructions Is the partial or complete blockage of the small or large intestine caused by a physical obstruction. Bowel incontinence Is the inability to control the excretion of feces. Jaundice Is a yellow discoloration of the skin, mucous membranes, and the eyes. This condition is caused by greater-than-normal amounts of bilirubin in the blood. Hepatitis Is an inflammation of the liver usually caused by a viral infection (hepat means liver, and -itis means inflammation). Constipation Is defined as having a bowel movement fewer than three times per week,with constipation, stools are usually hard, dry, small in size, and difficult to eliminate. Diarrhea Is an abnormally frequent flow of loose or watery stools that can lead to dehydration (dia- means through, and - rrhea means flow or discharge). Irritable bowel syndrome (IBS) Which is also known as spastic colon, is a common condition of unknown cause with symptoms that can include intermittent cramping, abdominal pain, bloating, constipation, and diarrhea. Hepatomegaly Is the abnormal enlargement of the liver (hepat/o means liver, and -megaly means enlargement). Cholecystitis Is inflammation of the gallbladder, usually associated with gallstones blocking the flow of bile (cholecyst means gallbladder, and -itis means inflammation). An enema Is the placement of a solution into the rectum and colon to empty the lower intestine through bowel activity. Stool samples are specimens of feces that are examined for content and characteristics Agastrectomy is the surgical removal of all or a part of the stomach (gastr means stomach, and -ectomy means surgical removal). Acolectomy Is the surgical removal of all or part of the colon (col means colon, and -ectomy means surgical removal). Acholecystectomy Is the surgical removal of the gallbladder (chole- means gallbladder, cyst means bladder, and -ectomy means surgical removal). Ahepatectomy Is the surgical removal of all or part of the liver (hepat means liver, and -ectomy means surgical removal). Aliver transplant Is an option for a patient whose liver has failed for a reason other than liver cancer. Melena abnormal black, tarry stool containing digested blood