Digestive system

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The stomach helps churn and digest food using gastric juices containing hydrochloric acid and pepsin to help break it down. This duct collects donations from the liver and the gall bladder bile as it passes along to the duodenum of the small bowel. Guyton and Hal Textbook of Medical Physiology 12th ed. Without going into specifics, cannabinoids signal to the body to create endocannabinoids and build more receptors. When to call your vet for vomiting.

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Human digestive system

Other related conditions include: Healthy Digestion the Natural Way by D. You must be logged in to post a comment. Food enters through the mouth and is broken down by saliva and the act of chewing. It passes through the esophagus until it reaches the stomach. The stomach uses acids and enzymes to convert food into a semi-liquid state called chyme.

The stomach then expels the chyme into the small intestine. The small intestine is the portal for all nutrients to enter into the bloodstream. Crucial digestive enzymes and hormones secreted from the pancreas, liver, and gallbladder break down the semi-liquid chyme into molecules small enough to be absorbed into the bloodstream. Any leftover food goes into the large intestine , where it is converted into solid waste with the help of bacteria.

Water and salts are extracted from any undigested food. The end-product is expelled through the rectum and anus. An unhealthy digestive system may be caused by: Chronic infections resulting from various organisms, bacteria, fungi, and viruses — An overgrowth of bacteria such as H. Food intolerances — Lactose and gluten intolerance can irritate the digestive system. On the inner surface of each cheek, opposite the second upper molar tooth, is a slight elevation that marks the opening of the parotid duct, leading from the parotid salivary gland , which is located in front of the ear.

Just behind this gland are four to five mucus-secreting glands, the ducts of which open opposite the last molar tooth. The roof of the mouth is concave and is formed by the hard and soft palate. The hard palate is formed by the horizontal portions of the two palatine bones and the palatine portions of the maxillae, or upper jaws.

The hard palate is covered by a thick, somewhat pale mucous membrane that is continuous with that of the gums and is bound to the upper jaw and palate bones by firm fibrous tissue. The soft palate is continuous with the hard palate in front. Posteriorly it is continuous with the mucous membrane covering the floor of the nasal cavity.

The soft palate is composed of a strong, thin, fibrous sheet, the palatine aponeurosis, and the glossopalatine and pharyngopalatine muscles.

A small projection called the uvula hangs free from the posterior of the soft palate. The floor of the mouth can be seen only when the tongue is raised. In the midline is a prominent, elevated fold of mucous membrane frenulum linguae that binds each lip to the gums, and on each side of this is a slight fold called a sublingual papilla , from which the ducts of the submandibular salivary glands open.

Running outward and backward from each sublingual papilla is a ridge the plica sublingualis that marks the upper edge of the sublingual under the tongue salivary gland and onto which most of the ducts of that gland open.

The gums consist of mucous membranes connected by thick fibrous tissue to the membrane surrounding the bones of the jaw. The gum membrane rises to form a collar around the base of the crown exposed portion of each tooth. Rich in blood vessels, the gum tissues receive branches from the alveolar arteries; these vessels, called alveolar because of their relationship to the alveoli dentales, or tooth sockets, also supply the teeth and the spongy bone of the upper and lower jaws, in which the teeth are lodged.

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Page 1 of Next page The teeth. Learn More in these related Britannica articles: It helps fight infection and keep body fluids in balance. The spleen is in charge of cleaning impurities from the blood, destroying old red blood cells and storing blood in case of emergency, such as an injury.

Stomach — The stomach acts as a storage tank for food so that the body has time to digest large meals properly.

This central organ not only holds the food, it also works as a mixer and grinder. The stomach contains hydrochloric acid and digestive enzymes that continue the digestion of food that began in the mouth. Enzymes and acids mix with the food that has already begun to break down in the mouth and esophagus, and it turns into a liquid called chyme.

Hydrochloric acid is a clear, colorless and highly pungent solution of hydrogen chloride in water. Liver — The liver is the second largest organ in the body, and it has many different functions. But the main function of the liver in digestion is the production of bile and its release into the small intestine. The liver makes and secretes bile, which helps enzymes in the body to break down fats into fatty acids. After we absorb nutrients through our small intestines, it then enters the bloodstream.

This blood is sent to the liver for filtering and detoxification. The liver has the amazing ability to break down and store amino acids, synthesize and metabolize fats and cholesterol, store glucose, detoxify the blood and regulate our internal functions. The gallbladder sits just under the liver and stores bile that is made in the liver, which then travels to the gallbladder through a channel called the cystic duct. The gallbladder stores bile between meals, and when we eat, the gallbladder squeezes bile through the bile ducts, which connect the gallbladder and liver to the small intestine.

Pancreas — The pancreas is a spongy, tube-shaped organ that is about six inches long. It secretes digestive enzymes into the small intestine, and this completes the chemical digestion of foods. Pancreatic juice is capable of digesting lipids, carbohydrates creating energy , proteins creating amino acids for building and nucleic acids. Both enzymes and hormones are needed to keep the body and digestive system working properly. The pancreas connects to the liver and the gallbladder with the common bile duct.

As pancreatic juices are made, they flow into the main pancreatic duct, and then join the common duct — which allows the bile which helps to digest fat break down food before it reaches the small intestine.

When the chyme our juices that are being digested leaves the stomach, it enters the small intestine through the pyloric sphincter — a muscle that serves as a valve and prevents the regurgitation of food from the intestine back into the stomach. It transforms from an acidic environment to an alkaline one, which means that the acids are neutralized. The small intestine is lined with very small protrusions that increase the surface area of the intestinal wall, which creates a larger absorption area.

Each protrusion, called villi, is covered in smaller hair-like structures, which are called microvilli.

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