Table of ContentsThe Digestive SystemThe Throat and StomachThe IntestinesWorks CitedThe Digestive SystemWhen you enter the body through the brain, you encounter the first component of the digestive system, the hypothalamus, a section of the brain the size of an almond. The hypothalamus controls body temperature, hunger, thirst, fatigue and circadian cycles. Daily cycle of biological activity based on a 24-hour period and influenced by regular variations in the environment, such as the night and day alternation displayed. by many organizations. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get an Original Essay As you progress through the body, the next component of the digestive system you arrive at is the mouth. The main digestive components of the mouth are the teeth and salivary glands. Teeth are a mechanical digester: they break food into smaller pieces through mastication (chewing). There are three main types of teeth in the mouth: incisors, canines and molars. The incisors – the first eight teeth, four on top and four on the bottom – cut food when you chew it. The next four teeth – two on top and two on the bottom – are the canines. The canines are used for tearing and tearing food. Other animals with canines use theirs to hold their prey. Molars – the last twenty teeth (in an adult) or last eight teeth (in a young child) – are used for chewing and grinding food. The different types of teeth total 32 for an adult and 20 for a young child. In addition to mechanical digestion in the mouth, there is chemical digestion: amylase present in saliva transforms starch (a polysaccharide (a carbohydrate made up of many sugar molecules stuck together)) into simple sugars – in progress. When food enters the mouth (is ingested), it is mixed with saliva secreted by several sets of glands. In addition to the many insignificant glands that secrete saliva, there are three main pairs of salivary glands: the parotid, submandibular, and sublingual glands. The parotid glands, the largest of the pairs, are located on the side of the face, below and below. in front of each ear. The submandibular glands, rounded in shape, are found near the inner surface of the lower jaw, in front of the sternomastoid muscle (the prominent muscle of the jaw). The sublingual glands lie directly beneath the mucous membrane covering the floor of the mouth, under the tongue. Saliva, produced by the tiny glands in the mouth and the three main glands, dissolves some of the chewed food and acts as a lubricant, allowing food to pass through the narrow passages of the digestive system. Saliva also contains a starch-digesting enzyme called amylase (ptyalin), which initiates the process of enzymatic hydrolysis (Hightower, MD Nicholas Carr. “Salivary Glands”. Encyclopedia Britannica Online. Encyclopedia Britannica, nd Web. September 30 2014.) Enzymatic Hydrolysis splits starch (a polysaccharide containing many sugar molecules linked in a continuous chain) into simple sugars. The Throat and Stomach The esophagus, the passage from the mouth to the stomach, is about 25 centimeters (10 inches) long. The esophagus contains 4 layers: the mucosa, the submucosa, the muscularis and the adventitia. The mucosa is made up of several layers of tissue containing numerous mucous glands. The submucosa is a thick filiform layer connecting the mucosa to the muscularis. The muscularis consists of an internal layer in which the fibersare circular and have an outer layer of fibers that extend lengthwise into the esophagus. The outer layer of the esophagus, the tunica adventitia, is composed of loose fibrous tissue that connects the esophagus to other internal structures. Except during the act of swallowing, the esophagus is normally empty and its channel is essentially closed by the longitudinal folds. mucosal and submucosal layers. The upper third of the esophagus is made up of striated (voluntary) muscles. The middle third is a mixture of striated and smooth (involuntary) muscle, and the lower third is all smooth muscle. The bolus (chewed food now mixed with saliva and moving down the esophagus) is moved by peristalsis. Peristalsis is the contraction of the muscles of the esophagus that move the bolus down the throat. The trachea connects near the middle of the esophagus. When you swallow, your brain sends a message to a flap of muscle called the epiglottis. The epiglottis closes over the windpipe during swallowing to prevent food from entering the windpipe. When the bolus reaches the end of the esophageal tube, the last thing stopping the bolus from reaching the stomach is the cardiac sphincter. The cardiac sphincter is a muscle that controls what goes in and out of the stomach. After passing the cardiac sphincter, the bolus enters the stomach. The bolus will be digested in the stomach over 3 to 4 hours. While the food is in the stomach, mechanical digestion takes place. Peristalsis, the contraction of the muscles around the stomach, causes the bolus to rise while the chemicals digest it. Chemical digestion in the stomach is caused by gastric juice composed of the enzyme pepsin and HCl (hydrochloric acid/muriatic acid). A thin layer of mucus lines the stomach to prevent hydrochloric acid, made up of hydrogen, chlorine and water, from burning in your stomach, causing stomach ulcers. Pepsin in the stomach is used to break down proteins. While pepsin digests proteins, hydrochloric acid also digests proteins and other elements present in the bolus. The stomach is shaped like a bean. There are 3 sections of the stomach: the fundus, the body and the pyloric end. The lower curve of the stomach is called the greater curvature because it is larger than the lesser curvature and the same is true. At the end of the stomach is the pyloric sphincter. The pyloric sphincter, like the cardiac sphincter, is a muscle that controls what enters the stomach and small intestine. Once the bolus passes through the pyloric sphincter, it is called chyme. The intestines The small intestine is made up of 3 parts: the duodenum, the jejunum and the ileum. The first 22 centimeters of the small intestine is the duodenum. Digestive enzymes are added into the duodenum. The digestive juices added to the small intestine are: pancreatic juice - amylase (turns starches into sugar), trypsin (breaks down proteins like pepsin) and lipase (breaks down fats) - and bile. Pancreatic juice (amylase, trypsin and lipase) is produced in the pancreas. Pancreatic juice participates in the digestion and absorption of nutrients in the small intestine. Enzymes in pancreatic juice help break down carbohydrates, proteins, and lipids (organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents) in chyme. The pancreas is made up of 3 sections: the head, body and tail. While the pancreas adds digestive juices to the small intestine, no food actually enters the pancreas. The pancreas is a digestive assistant (an organ that helps with digestion but never contains food). Bileis made in the liver. The liver is a digestive assistant like the pancreas. Once the liver produces bile, it sends the bile to be stored in the gallbladder via the hepatic ducts. Once in the gallbladder, the bile remains until it is needed. If bile contains too much cholesterol and sits around for too long, it can cause gallstones. Gallstones are an excess buildup of cholesterol in the gallbladder, causing a stone-like lump to form. When you pass a gallstone, you may feel a lot of pain. Now let's get back to the most important things. When needed, the gallbladder sends bile into the cystic duct, a tube connecting the gallbladder to the bile duct. As bile travels down the bile duct, it flows into the ampulla, a tube connecting the pancreas to the small intestine. When digestive enzymes reach the small intestine, they emulsify – mix – with the chyme to form an almost black liquid. Along with pancreatic juice, there is intestinal juice. Intestinal juice contains erepsin, lipase (breaks down fats), lactase (catalyzes the hydrolysis of lactose into glucose and galactose), enterokinase, amylase (transforms starches into sugar) and mucus. In the small intestine, mechanical digestion also takes place. While pepsin, trypsin and lipase present in pancreatic juice and erepsin, lipase, lactase, enterokinase and amylase present in intestinal juice chemically break down chyme, bile, a liquid mechanical digester , breaks down the “bits” of fat. in the chyme in small pieces. Peristalsis is another form of mechanical digestion in the small intestine. Although peristalsis is typically used to move food through the digestive system, the small intestine, like the stomach, also uses peristalsis to squeeze food. The next 200 centimeters of the small intestine is the jejunum. The jejunum is the part of the small intestine where pancreatic juice (chemical digestion in the small intestine) and bile (mechanical digester in the small intestine) digest chyme. Pepsin, trypsin and lipase present in pancreatic juice are chemical digesters. Peristalsis is again present in a digestive organ. Along the way are tiny structures called villi. The villi increase the surface area of ​​the small intestine by 600 times and absorb nutrients from the chyme. There are so many villi inside the small intestine that without the villi, the surface area of ​​the small intestine would be 600 times smaller. The last 350 centimeters of the small intestine is the ileum. In the ileum, the villi absorb nutrients from the chyme. The chyme has now reached the end of the small intestine and is now arriving at the ileocecal sphincter. The ileocecal sphincter allows what enters the large intestine. The large intestine is made up of 8 parts: the cecum, the appendix, the ascending colon, the transverse colon, the descending colon, the sigmoid colon, the rectum and the anus. The first part of the large intestine is the cecum. When food passes through the ileocecal sphincter, it reaches the cecum. The cecum is a bowl-shaped structure located in the large intestine. The appendix is ​​connected to the cecum. The appendix is ​​a worm-like tube that stores some of every type of bacteria in your large intestine in case the bacteria is killed in the intestine. The appendix sometimes becomes swollen and when this happens it causes a lot of pain. If the appendix swells, most people have an appendectomy. If left too long, the appendix can rupture and any bacteria stored in the appendix are.