explain human digestive system with diagram and all parts also explain????
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Answers
The human digestive system is a series of organs that converts food into essential nutrients that are absorbed into the body. The digestive organs also move waste material out of the body. The enzymes in saliva help break down foods, and the lubrication function of saliva makes it easier for food to be swallowed.
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PARTS OF DIGESTIVE SYSTEM:
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The process of digestion is a fascinating and complex one that takes the food we place in our mouth and turns it into energy and waste products. This process takes place in the gastrointestinal tract, a long, connected, tubular structure that starts with the mouth and ends with the anus. The food is propelled forward within the system, altered by enzymes and hormones into usable particles and absorbed along the way. Other organs that support the digestive process are the liver, gallbladder, and pancreas. The time it takes for food to travel from entering the mouth to be excreted as waste is around 30 to 40 hours.
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Mouth
The anterior opening of the alimentary canal is the mouth. It leads to a buccal cavity or oral cavity, where teeth, tongue and salivary glands are present. Here, ingestion, mastication, and swallowing of food occur. In humans, there are a total of 32 permanent teeth. There are four different types of teeth, namely, incisors, canines, premolars, and molars. These help in the chewing of food.
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Salivary Glands
They are exocrine glands that produce saliva in the oral cavity. They secrete an enzyme called amylase, which helps in the breakdown of starch into maltose. There are three types of salivary glands, namely:
- Parotid gland
- Submandibular gland
- Sublingual gland
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Stomach
The esophagus leads to a sac-like organ called the stomach. It is a muscular, hollow organ, having a capacity of 1 litre. The stomach holds food and also is a mixer and grinder. It secretes strong acids and powerful enzymes that help in the process of breaking down of food. Food is generally in a liquid or pastes consistency when it leaves the stomach.
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Small Intestine
The small intestine is a long tube, which loosely coils in the abdomen area. Here, enzymes from the pancreas and liver further break down the food. Three segments make up the small intestines, which are the duodenum, jejunum, and ileum. The contractions of the small intestine help in the movement of food, along with its breakdown, after mixing with the digestive secretions. The jejunum and ileum areas of the small intestine are responsible for the absorption of food into the blood, though their villi.
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Pancreas, Liver and Gall Bladder
These organs also play a significant role in the human digestive system. The pancreas secretes enzymes which help in the breakdown protein, fat, and carbohydrate. The liver secretes bile and cleanses and purifies the blood coming from the small intestine. The gallbladder stores the bile that the liver produces. It releases bile into the small intestine to aid in the digestion process.
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Large Intestine
The large intestine is a long muscular tube that has different parts, which are caecum, colon, and rectum. The waste that is left over after digestion of food, reaches the rectum through the peristaltic movements of the colon.
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Digestive System Controls
Hormones and nerves control the human digestive system. The walls of the alimentary canal have many sensors which regulate the digestive functions. Even hormones are involved in the digestion process. The main digestive hormone, gastrin is secreted in response to the presence of food. Gastrin again stimulates the gastric acid secretion. All these regulate the digestion process.
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