Скачать или смотреть મનુષ્યનું પાચનતંત્ર Manushyanu pachantantra मानव पाचक तंत्र Human Digestive System by J.R.Dangar

મનુષ્યનું પાચનતંત્ર
Manushyanu pachantantra
मानव पाचक तंत्र
Human Digestive System
by J.R.Dangar science
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The human digestive system
[ also known as the digestive tract ] is a series of connected organs leading from the mouth to the anus. The digestive system allows us to break down the food we eat to obtain energy and nourishment.

The digestive system -- which can be up to 30 feet in length in adults -- is usually divided into eight parts: the mouth, the esophagus, the stomach, the small intestine and the large intestine with the liver, pancreas, and gallbladder adding secretions to help digestion. These organs combine to perform six tasks: ingestion, secretion, propulsion, digestion, absorption, and defecation.

-The mouth starts the process by ingesting and mechanically breaking down the food we eat into a swallowable form, adding some early secretions to start the process of digestion. The esophagus is the muscular tube connecting the mouth to the stomach. A ring-like muscle at the end of the esophagus controls the passage of food into the stomach. This ring-like muscle also controls the food from going back up into the esophagus. The stomach then further liquefies the food and adds digestive acids.

-From there the stomach contents are slowly released into the small intestine. The small intestine is where most of the digestion and absorption of nutrients takes place. There are millions of tiny finger-like projections lining the small intestine called villi These villi aid in the absorption of nutrients.

-After traveling through the nearly 20 feet of small intestine, unabsorbed material moves into the colon. Here the remaining liquids and salts are absorbed from the digested material. Bacteria further break down the undigested material, which continues to solidify and eventually passes from the body as feces through the rectum and anus during a bowel movement.


The mouth and oesophagus

Digestion begins in the mouth. The food is ground up by the teeth and moistened with saliva to make it easy to swallow. Saliva also has a special chemical, called an enzyme, which starts breaking down carbohydrates into sugars. Once swallowed, muscular contractions of the oesophagus massage the ball of food down into the stomach.

The stomach

The food passes through a sphincter, or small muscle ring, into the stomach. Here it is mixed with gastric juices. The stomach is a muscular bag and it churns the food to help break it down mechanically as well as chemically. The food is then squeezed through a second sphincter into the first part of the small intestine, called the duodenum.

The small intestine

Once in the duodenum, the food is mixed with more digestive enzymes from the pancreas and bile from the liver. Food is then squeezed into the lower parts of the small intestine, called the jejunum and the ileum. Nutrients are absorbed from the ileum, which is lined with millions of finger-like projections called villi. Each villus is connected to a mesh of capillaries. This is how nutrients pass into the bloodstream.

Pancreas

The pancreas is one of the largest glands in the human body. As well as digestive juices, it secretes a hormone called insulin. Insulin helps to regulate the amount of sugar in the blood. Diabetes is a condition caused by problems with insulin production.

Liver

The liver has a number of different roles in the body, including:

breaking down fats, using bile stored in the gall bladder

processing proteins and carbohydrates

filtering and processing impurities, drugs and toxins

generation of glucose for short-term energy needs from other compounds like lactate and amino acids.

The large intestine

Once all the nutrients have been absorbed, the waste is moved into the large intestine, or bowel. Water is removed and the waste (faeces) is stored in the rectum. It can then be passed out of the body through the anus.


મનુષ્યનું પાચનતંત્ર

મુખથી મળદ્વાર સુધી લંબાયેલી લાંબી નળીને પાચનનળી કહે છે.
મુખગુહામાં દાંત, જીભ અને લાળગ્રંથિઓ આવેલી હોય છે.
[1] દાંત - તે ખોરાકને ચાવે છે.
[2] જીભ - તે ખોરાકને લાળરસ સાથે મિશ્ર કરે છે.
[3] લાળગ્રંથિઓ - તે લાળરસ નો સ્ત્રાવ કરે છે, જે ખોરાકને પોચો અને ભીનો બનાવે છે.
અન્નનળી દ્વારા ખોરાક મુખગુહા માંથી જઠરમાં આવે છે.
જઠર પાચનમાર્ગનો સૌથી પહોળો માર્ગ છે.
જઠરની દીવાલમાં જઠર ગ્રંથિઓ આવેલી હોય છે.
જઠર ગ્રંથિઓ [1] મંદ HCl [2] પેપ્સીન [3] શ્લેષ્મ નો સ્ત્રાવ કરે છે. આ મિશ્રણને જઠરરસ કહે છે.
જઠર પછી પાચનમાર્ગનું સૌથી લાંબામાં લાંબુ અને ગૂંચળામય અંગ નાનું આંતરડું આવે છે.
નાના આંતરડામાં ખોરાક સાથે [1] સ્વાદુરસ [2] પિતરસ [3] આંત્રરસ ભળે છે.
નાના આંતરડામાં ખોરાકના પાચનની ક્રિયા પૂર્ણ થાય છે.
નાના આંતરડામાં નહિ પચેલો ખોરાક મોટા આંતરડામાં જાય છે. ત્યાં માત્ર પાણીનું શોષણ થાય છે.
મળદ્વાર દ્વારા મળનું ઉત્સર્જન થાય છે.