Human Digestive System
Single-celled organisms can directly take in nutrients from their outside environment. Multi-cellular animals, with most of their cells removed from contact directly with the outside environment, have developed specialized structures for obtaining and breaking down their food. The human digestive system is a complex series of organs and glands that processes food. It is a coiled, muscular tube (6-9 meters long when fully extended) extending from the mouth to the anus. Inside this tube is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. This tube also includes the pharynx, esophagus, large intestine, and anus.
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At the junction of the esophagus and stomach, there is a ring like valve closing the passage between the two organs. However, as the food approaches the closed ring, the surrounding muscles relax and allow the food to pass. We can also swallow the food upside down because the muscles around the esophagus are strong enough to push the food up to our stomach.
The food then enters the stomach, a sack that receives the food from the esophagus. The stomach is located just below the heart. It has three mechanical tasks to do. First, the stomach stores the swallowed food and liquid. This requires the muscle of the upper part of the stomach to relax and accept large volumes of swallowed material. The second job is to mix up the food, liquid, and digestive juice (acids and enzymes - that help to break the food down into a thick liquid or paste called chyme) produced by the stomach. The lower part of the stomach mixes these materials by its muscle action. The third task of the stomach is to empty its contents slowly into the small intestine. Food usually remains in the stomach for about two hours.
After leaving the stomach the food enters the small intestine. The small intestine is a 20 to 25 foot tube that is coiled up in the abdomen. The center of the small intestine is right behind our belly button. The most important part of digestion takes place in the small intestine. As the thick liquid food paste travels
The esophagus receives food from the mouth after swallowing and then delivers it to the stomach. The stomach holds food which it is being mixed with enzymes which continue the process of breaking down the food into a useable form. When the contents of the stomach are processed they are released into the small intestine. In the small intestine food is broken down by enzymes released from the pancreas and bile from the liver, the food is moved through and mixed with digestive secretions. The small intestine is made up of three segments the duodenum, jejunum and the ileum, the jejunum and the ileum are mainly responsible from the absorption of nutrients in to the bloodstream. These contents start out semi-solid and end in a liquid form after passing through the organ. Water, bile, enzymes and mucous change its consistency, one the nutrients have been absorbed it then moves onto the large intestine. The large intestine connects to the rectum and is specialised in processing water so that emptying the bowels is easy.
Digestion starts in mouth and it is going through several steps. Teeth which are a Mechanical digestion start tearing and crushing the food down into small pieces so that the food will smoothly run down our throat. The salivary glands are located underneath the back of our tongues and that’s what is creating our saliva. The saliva is the Chemical Digestion is helping soften the food in the mouth so it is easy to swallow. Also saliva is the first out of several chemicals that is breaking the food into smaller bits. The tongue is the muscle that works with the food and saliva to form something similar to balls that can be swallowed. Also tongue contains taste buds so that we know if the food is salt, sweet, sour or bitter. Esophangus is a simple transportation tube that is joining the throat with stomach. When swallowing we are closing a trap door in our throats called the epiglottis. By closing this trap we are preventing the food prom going to trachea and into our lungs. Also Food moves down the esophangus using muscles not gravity. Stomach is the first stop after the Esophangus. When the food gets into stomach the stomach uses chemicals to try to make the food smaller. These chemicals are called gastric juices and they include hydrochloric acid and enzymes. (Enzymes are
Colon and rectum are both located in the digestive system. There are two parts of the digestive system. Upper part of the digestive system included stomach and small intestine, in which their job is to digest food for energy. Lower part of the digestive system are called gastrointestinal system, where colon and rectum are located. Its function is to absorb fluid to form solid waste then passes from the body as a stool. Small intestine made up of the most part of the digestive system, it is about 20 feet long. It break down the foods and absorb most of the nutrients. Then it pass to the large intestine which is mainly made up of a muscular tube, colon, and it is about 5 feet long. The colon can be divided into 4 section. Ascending colon, it is the beginning of the colon that included the cecum, where the appendix attaches to the colon. Transverse colon, the second section of the colon. It located in the upper abdomen and from the right to the left. The next section is called descending colon, the lower abdomen and from the left to right. The last section,
The digestion of the stomach wall is disallowed by its mucus lining. The food in the stomach takes about three to four hours in the stomach before the semi liquid chyme is passed through the pyloric sphincter bit by bit into the small intestines.
The digestive system is a group of organs working together to convert food into energy and basic nutrients to feed the whole body. To achieve the goal of providing energy and nutrients to the body, six processes take place in the digestive system.
The gastrointestinal tract (GI) also known as the Alimentary Canal is one of the two groups of organs composed in the digestive system. It is defined as a continuous tube that extends from the mouth to the anus through the thoracic and abdominopelvic cavities. Organs of the GI tract includes the mouth, most of the pharynx, esophagus, stomach, small intestines, and large intestines.
The process of digestion first begins in the mouth by in taking food (bolus). The teeth help with masticating (chewing and breaking food particles down) allowing for swallowing and increasing surface area for chemical digestion. Enzymes found in saliva also facilitates with the chemical break down of food primarily starches and fats. The food swallowed then enters into the esophagus (a tube connecting the mouth and stomach). Peristalsis helps the esophagus to push the food in the direction of the stomach. The stomach contents are highly acidic (doesn’t affect the stomach mucosa since cells secrete mucus allowing the stomach wall to be protected) with pH levels between 1.5-2.5 allowing microorganisms to be killed, breaking down of food, and activating digestive enzymes producing a thick substance known as chyme. However, breaking down of foods further occurs in the small intestine consisting of: bile created from the liver, enzymes formed from the small intestine, and the pancreas facilitate with further digestion as well as HCI denatures (unfolds proteins) allowing them to be available to attack by digestive enzymes (also responsible in breaking down the protein). The pyloric sphincter separates the stomach from the small intestine allowing the chime to drop into the small intestine. The small intestine is the primary site for
There aren’t many compartments the food has to travel through. Food travels down the esophagus into the stomach, where it is met by stomach acid and food is broken down and passed through the small and large intestine, nutrients are absorbed, and the waste is
As you can see, it is a tubelike structure made of muscle and lined with mucous membrane. The pharynx functions as part of the respiratory and digestive system because it is located behind the nasal cavities and the mouth. It is the structure that we refer to as the throat. It is about twelve and a half centimeters long and consists of three parts; the nasopharynx, oropharynx and the laryngopharynx. (Anatomy.tv, n.d.) The esophagus branches off of the pharynx which carries food to the stomach. Swallowing takes place in the pharynx partly as a reflex and partly under voluntary control. The tongue and soft palate pushes food into the pharynx, which closes off the trachea. The food then enters the esophagus. The esophagus is a muscular tube extending from the pharynx to the stomach. . (Mohan, 2010). It is about 25 centimeters long. The production of mucus by glands in the mucosal lining as you can see lubricates the tube to permit easier passage of food moving toward the stomach. (Thibodeau & Patton, 2008). Food is pushed through the esophagus and into the stomach by a series of contractions called peristalsis. The lower esophageal sphincter is just before the opening to the stomach. It opens to let food pass into the stomach and closes to keep it there. (Mohan, 2010).
Food is digested by being broken down, by a variety of enzymes, into useful nutrients, which are transported around the body to places where they can be of use, and into waste products, which are excreted from the body. The digestive system is made up of a number of organs, oesophagus, stomach, liver, pancreas, gallbladder, and small and large intestines, these are then separated into the digestive tract and the digestive organs. The digestive tract is, essentially, a single continuous tube that begins at the mouth and ends at the anus, in a fully grown adult it is approximately seven metres long. Food travels through the digestive tract and the digestive organs produce the enzymes and chemicals that are responsible for
The stomach is between the esophagus and small intestine that is in the upper left of the body. I can remember this by tracing the path in the photo.
Meanwhile, the salivary glands in your mouth are producing saliva, lubricating the food so it can make it’s way down your esophagus and into your stomach. Saliva contains enzymes, substances that make chemical reactions faster and that breaks down large starch molecules into smaller molecules of sugar. The first step of digestion is complete. Once your food gets to your stomach, the stomach starts to furtherly digest your food. Food in the stomach is digested chemically, with chief and parietal cells. Chief cells produce pepsin, which breaks down protein. Parietal cells produce hydrochloric acid (HCI). These cells and their products help to chemically break down food in the stomach. Once food has been mechanically and chemically digested, the food goes into the small intestine duodenum, which is the upper section of the small intestine. Attached to the duodenum is the pancreas and gallbladder. The pancreas is an organ that produces a variety of digestive enzymes, and the gallbladder is a storage sac that holds the bile produced in the liver. Bile is a chemical that breaks down fat droplets. The duodenum is also the organ that allows nutrients and water to pass through its walls. After completing its rounds in the duodenum, your digested food makes its way down into the small intestine, and then the large intestine. Villi in the small intestines absorbs nutrients into the bloodstream. The large intestine
Esophagus:- It is located inside of the trachea, near the windpipe that is responsible for the respiratory system, these two structures are separate by the epiglottis. A muscular movement that pulls the food downwards is called peristalsis.
The digestive system is very important in digesting food and breaking it down so it can be digested easily. The digestive system turns food into energy. Throughout the process there are nutrients which are absorbed. There are many things that contributed to the digestive system such as the mouth which produces saliva which helps to break down food and nutrients such as carbohydrates with the help of an enzyme called amylase. The major food groups which are called macro nutrients include carbohydrates, proteins and fats. All of these nutrients play an important role in the body. There are also many micro-nutrients which include vitamins and minerals which provide the body with health and well-being. The digestive system is made up of the mouth, which includes the teeth (the teeth are used to cut and grind food into smaller pieces, they contain blood vessels and nerves), tongue (the tongue is a muscle that has a rough surface including the taste buds), salvia glands (they produce salvia which moistens the food to make is easier to digest), the pharynx (this helps the food travel to the stomach, the pharynx also plays an important role in the respiratory system. It also contains 2 different flaps to separate the 2 functions), esophagus (this connects the pharynx to the stomach and transports chewed food to the stomach), stomach (this is a muscle that is
http://kidshealth.org/kid/cancer_center/HTBW/digestive_system.html ( I didnt copy direct quotes, however I had used the idea of the beginning in my research on the digestive system to help the reader better understand the system)