BIOD 103 MEDTERM EXAM MODULE 6 STUDY GUIDE 2024/2025 - PORTAGE LEARNING

Digestive (Gastrointestinal) System The gastrointestinal, or GI, system can also be called the alimentary, or digestive, tract. This system is a tube-like passageway that starts at the mouth and ends at the anus. It functions to: 1. transport food for digestion 2. prepare food for absorption 3. transport waste products for elimination from the body Digestion: The Esophagus & the Stomach From the esophagus, food enters the stomach, which can be broken down into three distinct parts. The upper part of the stomach is called the fundus, the middle portion is known as the body, and the lower portion is known as the antrum. The openings to and from the stomach are called sphincters. These sphincters contract and relax to allow food in from the esophagus and push food out of the stomach and into the small intestine. The esophageal sphincter allows food into the stomach for further peristalsis to take place, while the pyloric sphincter allows food to exit the stomach when it has been sufficiently broken down. The lining of the stomach consists of folds, called rugae, which allow it to stretch when food enters to be broken down. Within the stomach, food is broken down chemically into a substance called chyme. Once it reaches this state, it travels into the small intestine in small amounts to be absorbed for nutrition by the body and for further digestion. Three Accessory Organs Before we continue, let’s discuss three accessory organs that play a major role in digestion: the liver, pancreas, and gall bladder. The liver produces a substance called bile that aids in the breakdown of food. This bile is stored in the gall bladder. The pancreas also produces digestive enzymes called amylase and lipase, which also aid in the breakdown of food. After a meal when the stomach is full, the gall bladder contracts and releases bile into the small intestine to breakdown food that enters the small intestine from the stomach. The pancreas also releases digestive enzymes into the small intestine via the pancreatic duct. Digestion: The Stomach & the Small Intestine Food exits the stomach through the pyloric sphincter and enters the small intestine, suthe duodenum. It is here that chyme is mixed with bile and digestive enzymes from the pancreas for further digestion before it enters the second part of the small intestine, known as the jejunum. The jejunum runs into the third and final portion of the small intestine, called the ileum. It is within the ileum that most nutrient absorption takes place. Throughout the wall of the small intestine are microscopic finger-like projections known as villi. Nutrient absorption occurs through capillaries located within these villi. These nutrients pass through the capillaries and into the blood stream and lymph vessels to either be used by the body tissues or eliminated as waste. Digestion: The Oral Cavity & the Esophagus Digestion begins in the oral cavity, or the mouth. We voluntarily take food into our mouths where the teeth, through the process of chewing (mastication), break the food down into smaller pieces to ease the process of digestion. Also located in the oral cavity are three pairs of salivary glands that release digestive enzymes to help to further break down the food. The tongue muscle, which is covered in raised projections called papillae (or taste buds), helps to push the food from the mouth into the pharynx and from there to the esophagus. The esophagus is the bridge between the mouth and the stomach. It is here the peristalsis begins. As discussed in earlier modules, smooth muscle, located throughout the GI tract, acts to propel food through the system for digestion, absorption, and ultimately elimination. The process of peristalsis is under involuntary control. Digestion: The Small Intestine, the Large Intestine, & the Rectum The small intestine joins the large intestine through the ileocecal valve. The large intestine can be broken down into four distinct parts: the cecum, colon, sigmoid colon, and the rectum. The appendix is attached to the cecum and serves to function within our body’s immune system. From the cecum, we reach the colon, which can also be further subdivided into the ascending, transverse, and descending colon. The sigmoid colon is “S” shaped and located at the end of the descending colon. It leads to the final portion of the large intestine, or the rectum. The rectum ends through the termination point of the GI tract, the anus. The large intestine stores waste products that cannot be absorbed for nutritional use by the body. This waste is stored until it can be released from the body through fecal matter. The following tables represent root words, prefixes, suffixes, and common pathologies that relate to the gastrointestinal system. Please note that many of these root words, prefixes, and suffixes are review from Module 1; however, you should also be familiar with new words specific to this system. Table 6.1: Common Root Words Related to the GI System and Their Meanings Root Word Meaning An (o) Anus Append (o) Appendix Appendic (o) Bucc (o) Cheek Cec (o) Cecum Celi (o) Belly Chol (e) Gall or Bile Cholecyst (o) Gallbladder Col (o) Colon (o) Colon Dent (o) Odont (o) Teeth Duoden (o) Duodenum Enter (o) Small intestine Esophag (o) Esophagus Gastr (o) Stomach Gingiv (o) Gums Hepat (o) Liver Ile (o) Ileum Jejun (o) Jejunum Labi (o) Lips Lingu (o) Gloss (o) Tongue Or (o) Mouth Pancreat Pancreas BIOD 103 MEDTERM MODULE 6 STUDY GUIDE/PORTAGE LEARNING (o) Peritone (o) Pharyng (o) Proct (o) Rect (o) Peritoneum Pharynx Rectum, anus Sigmoid (o) Sigmoid colon Table 6.2: Prefixes and Suffixes Used to Relate to the GI System and Their Meanings Prefix/Suffix Meaning Pre- Before Post- After Retro- Backward -ase Enzyme -flux Flow BIOD 103 MEDTERM MODULE 6 STUDY GUIDE/PORTAGE LEARNING BIOD 103 MEDTERM MODULE 6 STUDY GUIDE/PORTAGE LEARNING -iasis -lith -lytic -pepsia - prandia l Abnormal condition Calculus or stone Breakdown Digestion Meal - ostomy Creation of an artificial opening -tresia Opening -tripsy Crushing Table 6.3: Common Pathologies Affecting the GI System Ascite s fluid accumulation within the abdomen Cirrhosis chronic disease of the liver Diverticulosis formation of bulging sacs from the large intestine Diverticulitis inflammation or infection of these bulging sacs Hemorrhoids mass of enlarged and twisted varicose veins in the mucous membrane located inside or just outside of the rectum Hernia protrusion of an organ through the wall of the cavity that normally contains it BIOD 103 MEDTERM MODULE 6 STUDY GUIDE/PORTAGE LEARNING For each row, type the letter from the meaning in Column B that matches the corresponding term in Column A: