explain human digestive system ?

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koi answer batao yaar

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digestive system The human digestive system is a complex series of organs and glands that processes food. In order to use the food we eat, our body has to break the food down into smaller molecules that it can process; it also has to excrete waste.

Most of the digestive organs (like the stomach and intestines) are tube-like and contain the food as it makes its way through the body. The digestive system is essentially a long, twisting tube that runs from the mouth to the anus, plus a few other organs (like the liver and pancreas) that produce or store digestive chemicals.

The Digestive Process:
The start of the process - the mouth: The digestive process begins in the mouth. Food is partly broken down by the process of chewing and by the chemical action of salivary enzymes (these enzymes are produced by the salivary glands and break down starches into smaller molecules).

On the way to the stomach: the esophagus - After being chewed and swallowed, the food enters the esophagus. The esophagus is a long tube that runs from the mouth to the stomach. It uses rhythmic, wave-like muscle movements (called peristalsis) to force food from the throat into the stomach. This muscle movement gives us the ability to eat or drink even when we're upside-down.

In the stomach - The stomach is a large, sack-like organ that churns the food and bathes it in a very strong acid (gastric acid). Food in the stomach that is partly digested and mixed with stomach acids is called chyme.

In the small intestine - After being in the stomach, food enters the duodenum, the first part of the small intestine. It then enters the jejunum and then the ileum (the final part of the small intestine). In the small intestine, bile (produced in the liver and stored in the gall bladder), pancreatic enzymes, and other digestive enzymes produced by the inner wall of the small intestine help in the breakdown of food.

In the large intestine - After passing through the small intestine, food passes into the large intestine. In the large intestine, some of the water and electrolytes (chemicals like sodium) are removed from the food. Many microbes (bacteria like Bacteroides, Lactobacillus acidophilus, Escherichia coli, and Klebsiella) in the large intestine help in the digestion process. The first part of the large intestine is called the cecum (the appendix is connected to the cecum). Food then travels upward in the ascending colon. The food travels across the abdomen in the transverse colon, goes back down the other side of the body in the descending colon, and then through the sigmoid colon.

The end of the process - Solid waste is then stored in the rectum until it is excreted via the anus.

Digestive System Glossary:
abdomen - the part of the body that contains the digestive organs. In human beings, this is between the diaphragm and the pelvis
alimentary canal - the passage through which food passes, including the mouth, esophagus, stomach, intestines, and anus.
anus - the opening at the end of the digestive system from which feces (waste) exits the body.
appendix - a small sac located on the cecum.
ascending colon - the part of the large intestine that run upwards; it is located after the cecum.
bile - a digestive chemical that is produced in the liver, stored in the gall bladder, and secreted into the small intestine.
cecum - the first part of the large intestine; the appendix is connected to the cecum.
chyme - food in the stomach that is partly digested and mixed with stomach acids. Chyme goes on to the small intestine for further digestion.
descending colon - the part of the large intestine that run downwards after the transverse colon and before the sigmoid colon.
digestive system - (also called the gastrointestinal tract or GI tract) the system of the body that processes food and gets rid of waste.
duodenum - the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum.
epiglottis - the flap at the back of the tongue that keeps chewed food from going down the windpipe to the lungs. When you swallow, the epiglottis automatically closes. When you breathe, the epiglottis opens so that air can go in and out of the windpipe.
esophagus - the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called peristalsis) to force food from the throat into the stomach.
gall bladder - a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical which is produced in the liver) into the small intestine.
gastrointestinal tract - (also called the GI tract or digestive system) the system of the body that processes food and gets rid of waste.
ileum - the last part of the small intestine before the large intestine begins.
intestines - the part of the alimentary canal located between the stomach and the anus.
jejunum - the long, coiled mid-section of the small intestine; it is between the duodenum and the ileum.
liver - a large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins.
mouth - the first part of the digestive system, where food enters the body. Chewing and salivary enzymes in the mouth are the beginning of the digestive process (breaking down the food).
pancreas - an enzyme-producing gland located below the stomach and above the intestines. Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine.
peristalsis - rhythmic muscle movements that force food in the esophagus from the throat into the stomach. Peristalsis is involuntary - you cannot control it. It is also what allows you to eat and drink while upside-down.
rectum - the lower part of the large intestine, where feces are stored before they are excreted.
salivary glands - glands located in the mouth that produce saliva. Saliva contains enzymes that break down carbohydrates (starch) into smaller molecules.
sigmoid colon - the part of the large intestine between the descending colon and the rectum.
stomach - a sack-like, muscular organ that is attached to the esophagus. Both chemical and mechanical digestion takes place in the stomach. When food enters the stomach, it is churned in a bath of acids and enzymes.
transverse colon - the part of the large intestine that runs horizontally across the abdomen.

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Complex components of food such as carbohydrates are broken down into simpler substances and are then utilized by the body. This process of breaking down of complex substances into simpler substances is known as digestion.The human digestive system consists of a number of organs, each performing a different function.

 

 

In the digestive system, food first enters the buccal cavity. The buccal cavity consists of teeth and the tongue. Apart from the tongue and the teeth, the buccal cavity also has salivary glands, which secrete saliva. The enzymes present in saliva breakdown the fats or digest the starch present in the food we eat. The swallowed food passes into the oesophagus from the mouth. The oesophagus or the food pipe runs along the neck and chest. The walls of the food pipe move to push the food down into the stomach. After the food pipe, the food enters the stomach. The stomach is a thin-walled bag. It is flattened, U-shaped, and is the widest part of the alimentary canal. It opens into the small intestine. The inner lining of the stomach secretes hydrochloric acid, mucous, and digestive juices. The mucus secreted by the stomach protects the inner lining of the stomach. The hydrochloric acid secreted by the stomach kills the bacteria that enter the stomach through food. It also makes the medium of the stomach acidic. The digestive juices secreted by the stomach take part in the process of digestion by breaking down the food into smaller substances. The stomach empties its contents into the small intestine. The small intestine is a highly coiled, tube-like structure. It is about 7.5 metres in length. It receives secretions from the liver and the pancreas in the form of bile and pancreatic juice. Apart from this, the wall of the small intestine also secretes juices. When the partly digested food reaches the small intestine, the juices secreted by the small intestine complete the process of digestion. Nutrients from the digested food pass into blood vessels, which are present in the walls of the small intestine. This process is known as absorption. From the small intestine, the food is passed on to the large intestine where the water and remaining salts gets absorbed. The remaining waste material then enters the rectum. It is stored there in the form of semi-solid faeces. The faecal material is finally removed from the body through the anus. This process is known as egestion.

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 In the digestive system, food first enters the buccal cavity. The buccal cavity consists of teeth and the tongue. Apart from the tongue and the teeth, the buccal cavity also has salivary glands, which secrete saliva. The enzymes present in saliva breakdown the fats or digest the starch present in the food we eat. The swallowed food passes into the oesophagus from the mouth. The oesophagus or the food pipe runs along the neck and chest. The walls of the food pipe move to push the food down into the stomach. After the food pipe, the food enters the stomach. The stomach is a thin-walled bag. It is flattened, U-shaped, and is the widest part of the alimentary canal. It opens into the small intestine. The inner lining of the stomach secretes hydrochloric acid, mucous, and digestive juices. The mucus secreted by the stomach protects the inner lining of the stomach. The hydrochloric acid secreted by the stomach kills the bacteria that enter the stomach through food. It also makes the medium of the stomach acidic. The digestive juices secreted by the stomach take part in the process of digestion by breaking down the food into smaller substances. The stomach empties its contents into the small intestine. The small intestine is a highly coiled, tube-like structure. It is about 7.5 metres in length. It receives secretions from the liver and the pancreas in the form of bile and pancreatic juice. Apart from this, the wall of the small intestine also secretes juices. When the partly digested food reaches the small intestine, the juices secreted by the small intestine complete the process of digestion. Nutrients from the digested food pass into blood vessels, which are present in the walls of the small intestine. This process is known as absorption. From the small intestine, the food is passed on to the large intestine where the water and remaining salts gets absorbed. The remaining waste material then enters the rectum. It is stored there in the form of semi-solid faeces. The faecal material is finally removed from the body through the anus. This process is known as egestion.

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The digestive system  is concerned with the breakdown of complex food substances and its conversion in to simpler components , its absorption through the blood stream and  assimilation in the cells and tissues producing desired effects of growth etc.The digestive system  in man comprises of  different components each assigned with a specific function.Basically, the the digestive system can be considered as a the food pipe or esophagus  initiating  from the buccal cavity or mouth and terminating in the anus with diversifications at different stages  of its  progression  form the mouth to anus.

 Components of the  digestive system  in human  body:
  The digestive system in  human body comprises of the following: 
                                             digesrtive system in humajn body

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Digestive organs and their functions

(i) Mouth:Digestion of food begins in the mouth. The mouth comprises of the following:

Teeth: They tear and break down the food.

Saliva: It contains a digestive enzyme called salivary amylase, which breaks down starch into sugar.

Tongue: It is a sense organ with taste buds, which help us to differentiate between various food items. The muscular movements in the tongue move the food from the mouth into the throat, or pharynx.

(ii) Pharynx:It is a common passageway for food and air. It opens into the oesophagus (which leads to the stomach) and trachea (which leads to the lungs).

(iii) Oesophagus:The circular smooth muscles in the oesophagus contract when food is swallowed. This prevents the chewed food material from moving back into the mouth. This is followed by the contractions and relaxations of the longitudinal smooth muscles, which push the digested food forward. These movements are called peristaltic movements, which push the food into the stomach.

(iv) Stomach:The stomach stores and mixes the food received from the oesophagus with the gastric juice. The gastric glands present in the walls of the stomach secrete several substances, which together constitute the gastric juice.

The main components of gastric juice are hydrochloric acid, mucus, and pepsinogen.

Hydrochloric acid dissolves bits of food and creates an acidic medium. In this medium, pepsinogen is converted to pepsin, which is a protein-digesting enzyme.

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