The Human Digestive System - Diagram. The esophagus is a long muscular tube, which moves food from the mouth to the stomach. The abdomen contains all of. Find out what your insides look like by looking at pictures and read a quick overview of how each part helps you to digest your food.
ReviewThe digestive system plays an important role in the absorption of nutrients into the body. It takes the food we ingest, breaks it down mechanically and chemically in the mouth and stomach. It then absorbs nutrients, fats, proteins and water in the intestines before eliminating the waste through the rectum.Major organs involved in the digestive system include the mouth, stomach, small intestine, large intestine, liver, pancreas. The main steps in the digestive systemThe digestive system is designed to do a few major things. They can be grouped into four categories:. Ingestion.
Digestion. Breakdown. ExcretionFollowing Food from Mouth to AnusTo understand how our food is digested in the digestive system, it might be very useful to follow our food along its normal path, starting from the mouth.Imagine for just a second that you’re hungry and your eyes gaze upon a nice home cooked thanksgiving turkey dinner. Your mouth starts to water.
The salivary glands in your mouth are triggered to start producing saliva, a compound that will aid in the digestion of the meal.As food enters your mouth, your teeth begin mechanically breaking down the food into small and smaller pieces. The saliva starts to chemically break it down as well. Soon, your conscious mind says, “lets swallow this food.” You swallow it and take another bite.While you’re thinking about your next bite of food, your nervous system is helping to move the bolus (the food package you swallowed), down throat. A small flap of skin called your epiglottis makes sure your food goes down your esophagus.
Movements of the smooth muscles, known as peristalsis help move that bolus down your esophagus. When it reaches your stomach, a sphincter opens and dumps the food in.Inside the stomach, cells start to secrete different acids that help increase acidity to a pH of 2. This strong acidic environment kills most bacteria and starts to chemically break apart the food. Movements of the smooth muscles in the stomach, known as peristalsis mix and churn the food up more. After the food has been well mixed and has a consistency of oatmeal, it is ready to move to the small intestine. At this stage it is known as chyme.To move into the small intestine, chyme must pass through the pyloric sphincter. From here it enters the duodenum, the first part of the small intestine.
The liver mixes in bile, which helps break down fats in the food. The pancreas also secretes digestive enzymes that aid in digestion.Most of the nutrients are absorbed from the small intestine and moved into the blood stream via a system of small folds, called vili.After the food moves through the small intestine it enters the large intestine. The large intestine is named for the diameter of the cavity and not for the length.
It is actually much shorter than the small intestine. The role of the large intestine is to remove any extra water from the digested material before it is finally excreted.So there you have it – a basic rundown of what happens to the food we eat from the time we eat it, to when we excrete it. While we didn’t go into detail on all the steps, we would encourage you to explore as much as you can about each step of the process.
Review our links below for more detailed explanations of the entire process.Digestive System Vocabulary Terms. Anus: located at the end of the digestive system.
The function of the anus is to expel feces, and unwanted semi-solid material produced during digestion. Appendix: a pouch like structure of the colon.
The appendix is located near the junction of the small and large intestines. It is often referred to as the vermiform appendix or cecal appendix. The appendix is thought to be a vestigial structure in humans (an organ that has lost its original function). Today the appendix is prone to infection is often removed at the first sign of a problem. Ascending Colon: The large intestine can be divided up into different regions.
The first section that takes digested material up is the ascending colon. It is smaller in caliber than the cecum, with which it is contiguous. Bile: yellowish, blue and green fluid secreted from the liver.
Bile is sometimes called gall and is stored in the gallbladder between meals. It is secreted into the duodenum to aid int eh process of digestion of lipids via emulsification. Cecum: the beginning of the large intestine.
The cecum is a pouch that connects the ileum with eh ascending colon. Chyme: the name given to the partially digested food that leaves the stomach via the pyloric valve into the small intestine (duodenum). Chyme, also known as chymus has the consistency of oatmeal.
Descending Colon: the region of the large intestine that moves digested material downward through the left hypochondrium and lumbar regions. Duodenum: the first section of the small intestine.
This hollow, jointed tube is only about 10-12 inches long. It connects the stomach to the jejunum and is where most of the chemical digestion takes place. Epiglottis: a small flap of elastic cartilage just below the pharynx that helps direct food down the esophogus and direct air into the lungs.
Without the epiglottis, it would be difficult to. Esophagus: a muscular tube that allows food to pass from the pharynx to the stomach. Through peristalsis the esophagus is able to push food from the pharynx to the stomach, even if the individual is standing on their head. Gall Bladder: a small organ that stores bile produced in the liver. It can hold about 50 mL of bile.
Ileum: the last region of the small intestine. The ileum follows the other small intestine regions known as the duodenum and the jejunum. After the ileum, digestive material must pass through the ileocecal valve to get to the cecum. Jejunum: the middle section of the small intestine.
It is preceded by the duodenum and followed by the ileum. Liver: a vital organ that produces chemicals necessary for digestion.
In digestion it is extremely important in producing bile, which helps break down fats. Mouth: Often considered the first step in the digestive process. The chewing action of the mouth serves to mechanically break down food particles. Saliva produced here helps in chemical breakdown of food. Pancreas: an organ that aids in both the digestive system and the endocrine system. It aids in the digestive system by producing pancreatic juices, which contain digestive enzymes, which pass through the small intestine. These juices help break down carbohydrates, protien and fat in the chyme.
Peristalsis: a radially symmetrical contraction of muscles that propagate down a tube. It occurs especially in the esophagus and the stomach. This movement helps the stomach mix up and break down our food. Rectum: the last portion of the large intestine. Human rectums are about 12cm long.
Saliva: a substance produced by the salivary glands that aids in digestion. Human saliva is about 98% water.
The other 2% consists of electrolytes, mucus, and antibacterial compounds. Salivary Glands: an exocrine gland that produces saliva, and amylase, among others.
Sigmoid Colon: a loop of the large intestine about 40 cm long. It is the closest part of the large intestine to the rectum and anus. Stomach: a muscular organ in the gastrointestinal tract that helps churn up and digest food. The stomach lies between the esophagus and the small intestine. Smooth muscles in the stomach help to break down food mechanically via peristalsis. Transverse Colon: the longest and most movable part of the colon.
It is the section of the large intestine just after the ascending colon and just before the descending colon.Links to other Digestive System Resources.As you may have gathered from the above information, the digestive system is a complex and intricate part of the body. A number of things can go wrong with this system and when they do illnesses can be severe and lower a person’s quality of life significantly. You can learn more about these.
Structure of the Digestive System What organs make up the digestive system?Your digestive system is uniquely constructed to perform its specialized function of turning food into the energy you need to survive and packaging the residue for waste disposal. To help you understand how the many parts of the digestive system work together, here is an overview of the structure and function of this complex system.MouthThe mouth is the beginning of the digestive tract; and, in fact, digestion starts here when taking the first bite of food. Chewing breaks the food into pieces that are more easily digested, while saliva mixes with food to begin the process of breaking it down into a form your body can absorb and use. EsophagusLocated in your throat near your trachea (windpipe), the esophagus receives food from your mouth when you swallow. By means of a series of muscular contractions called peristalsis, the esophagus delivers food to your stomach.
StomachThe stomach is a hollow organ, or 'container,' that holds food while it is being mixed with enzymes that continue the process of breaking down food into a usable form. Cells in the lining of the stomach secrete a strong acid and powerful enzymes that are responsible for the breakdown process. When the contents of the stomach are sufficiently processed, they are released into the small intestine. Small intestineMade up of three segments - the duodenum, jejunum, and ileum - the small intestine is a 22-foot long muscular tube that breaks down food using enzymes released by the pancreas and bile from the liver.
Peristalsis also is at work in this organ, moving food through and mixing it with digestive secretions from the pancreas and liver. The duodenum is largely responsible for the continuous breaking-down process, with the jejunum and ileum mainly responsible for absorption of nutrients into the bloodstream.Contents of the small intestine start out semi-solid, and end in a liquid form after passing through the organ. Water, bile, enzymes, and mucous contribute to the change in consistency.
Once the nutrients have been absorbed and the leftover-food residue liquid has passed through the small intestine, it then moves on to the large intestine, or colon. PancreasThe pancreas secretes digestive enzymes into the duodenum, the first segment of the small intestine. These enzymes break down protein, fats, and carbohydrates. The pancreas also makes insulin, secreting it directly into the bloodstream. Insulin is the chief hormone for metabolizing sugar. LiverThe liver has multiple functions, but its main function within the digestive system is to process the nutrients absorbed from the small intestine. Bile from the liver secreted into the small intestine also plays an important role in digesting fat.
In addition, the liver is the body's chemical 'factory.' It takes the raw materials absorbed by the intestine and makes all the various chemicals the body needs to function. The liver also detoxifies potentially harmful chemicals.
It breaks down and secretes many drugs. GallbladderThe gallbladder stores and concentrates bile, and then releases it into the duodenum to help absorb and digest fats. Colon (large intestine)The colon is a 6-foot long muscular tube that connects the small intestine to the rectum.
The large intestine is made up of the cecum, the ascending (right) colon, the transverse (across) colon, the descending (left) colon, and the sigmoid colon, which connects to the rectum. The appendix is a small tube attached to the cecum. The large intestine is a highly specialized organ that is responsible for processing waste so that emptying the bowels is easy and convenient.Stool, or waste left over from the digestive process, is passed through the colon by means of peristalsis, first in a liquid state and ultimately in a solid form. As stool passes through the colon, water is removed. Stool is stored in the sigmoid (S-shaped) colon until a 'mass movement' empties it into the rectum once or twice a day. It normally takes about 36 hours for stool to get through the colon.
The stool itself is mostly food debris and bacteria. These bacteria perform several useful functions, such as synthesizing various vitamins, processing waste products and food particles, and protecting against harmful bacteria. When the descending colon becomes full of stool, or feces, it empties its contents into the rectum to begin the process of elimination. RectumThe rectum (Latin for 'straight') is an 8-inch chamber that connects the colon to the anus. It is the rectum's job to receive stool from the colon, to let the person know that there is stool to be evacuated, and to hold the stool until evacuation happens. When anything (gas or stool) comes into the rectum, sensors send a message to the brain.
The brain then decides if the rectal contents can be released or not. If they can, the sphincters relax and the rectum contracts, disposing its contents. If the contents cannot be disposed, the sphincter contracts and the rectum accommodates so that the sensation temporarily goes away. AnusThe anus is the last part of the digestive tract. It is a 2-inch long canal consisting of the pelvic floor muscles and the two anal sphincters (internal and external). The lining of the upper anus is specialized to detect rectal contents.
It lets you know whether the contents are liquid, gas, or solid. The anus is surrounded by sphincter muscles that are important in allowing control of stool. The pelvic floor muscle creates an angle between the rectum and the anus that stops stool from coming out when it is not supposed to. The internal sphincter is always tight, except when stool enters the rectum.
It keeps us continent when we are asleep or otherwise unaware of the presence of stool. When we get an urge to go to the bathroom, we rely on our external sphincter to hold the stool until reaching a toilet, where it then relaxes to release the contents.