What are the various steps of …

Ingestion:

• In human beings, food is ingested through the mouth. The food is put into the mouth with the help of hands.

Digestion:

• The digestion of food commences in the mouth itself.
• The teeth cut the pabulum into small pieces, masticate and grind it. (Physical digestion)
• The salivary glands in our mouth produce saliva (watery liquid) which contains an enzyme salivary amylase which digests the starch (carbohydrate) present in the food into sugar. (Chemical digestion)
• Our tongue helps in mixing this saliva with food.
• The digestion of food remains incomplete in the mouth.

Oesophagus:

• The slightly digested food in the mouth is swallowed by the tongue and goes down the food pipe called oesophagus.
• When the marginally digested food enters the victuals pipe, the walls of victuals pipe start contraction and expansion forms of kineticism called as a peristaltic movement.
• This peristaltic movement of food pipe pushes the slightly digested into the stomach.

Stomach:

• The stomach is a J-shaped organ present on the left side of the abdomen.
• The stomach walls contain s three tubular glands in it walls which secrete gastric juice.
• The gastric juice contains three substances: Hydrochloric acid, the enzyme pepsin, and mucus.
• The hydrochloric creates an acidic medium which facilitates the action of the enzyme pepsin i.e. digestion of protein.
• The mucus helps to protect the stomach wall from its own secretions of hydrochloric acid.
• The partially digested food then goes from the stomach into the small intestine.

Small intestine:

• From the stomach, the partially digested food enters the small intestine.
• The small intestine is the largest part (about 6.5 m) of the alimentary canal.
• The small intestine is very slight and arranged in the form of a coil in our belly.
• The small intestine in human beings is the site of complete digestion of food (like carbohydrates, proteins, and fats)
• The small intestine receives the secretion of two glands: Liver and Pancreas.
• The liver secretes bile (greenish yellow liquid made in the liver and stored in the gallbladder).
• Bile performs two functions:
  1. Makes the acidic food coming from the stomach alkaline so that pancreatic enzymes can act on it.
  2. Bile salts shatter the fats present in the food into small globules making it easy for the enzymes to act and digest them.
• The pancreas secretes pancreatic juice which contains enzymes like pancreatic amylase for breaking down starch, trypsin for digesting proteins and lipase for breaking down emulsified fats.
• The walls of the small intestine contain glands which produce intestinal juice. The enzymes present in it finally convert the proteins into amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.
• In this way, the process of digestion converts the sizably voluminous and insoluble aliment molecules into small water-soluble molecules.

Absorption:

• The small intestine is the main region for the absorption of digested food.
• The inner surface of the minute intestine has numerous finger-like projections called villi which increase the surface area for rapid absorption of digested food.
• The digested food which is absorbed through the walls of the small intestine goes into our blood.

Assimilation:

• The blood carries digested and dissolved food to all the components of the body where it becomes assimilated as a component of the cells and is utilized for obtaining energy, building up new tissues and the repair of old tissues.

Egestion:

• The unabsorbed food is sent into the large intestine where more villi absorb water from this material.
• The rest of the material is abstracted from the body via the ****.
•  The exit of this waste material is regulated by the **** sphincter.