Question

nutritions in human​

Answer 1

Answer:

Nutrition is very important for human beings for their development , protection from diseases and body building.there are many types of nutrients like- vitamins, minerals, proteins fats and carbohydrates which should be taken by everyone in balanced diet.

Explanation:

energy giving nutrients- fats and carbohydrates.

protective nutrients- vitamins and minerals.

body building nutrients - protiens.

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Answer 2

$\bigstar\overbrace{ \underbrace{ \bold{NUTRITION \: IN \: HUMANS}}}$

Nutrition in humans follows the five steps those are Ingestion, Digestion, Absorption, Assimilation and Egestion. The digestive system is composed of several organs: the mouth, oesophagus, stomach, small intestine, large intestine, rectum and anus. These organs form the long tube-like alimentary canal through which the food we eat passes. The salivary glands, pancreas and liver are accessory organs that secrete digestive juices into the alimentary canal.

☯Ingestion and Digestion in the Mouth.

The mouth is the place where the food enters the alimentary canal. The main function of the mouth is to chew the food before it is sent to the oesophagus. The process of chewing the food is called mastication.

The salivary glands secrete saliva into the mouth. The saliva contains digestive juices that digest carbohydrates It also moistes the food, making it easier to swallow Thus, the process of digestion begins in the mouth.

The mouth is also used for other functions like talking and singing,

◉Teeth

The teeth are used to bite and chew the food. They cut and grind food to break it down into smaller particles. Since humans are omnivores, they have all the types of teeth in their mouth.

There are four types of teeth in the human mouth.

• Incisors : are the teeth found in the front of the mouth. They are chisel-shaped and mainly used for biting and cutting food.

• Canines : are pointed and used for piercing and tearing food into smaller pieces.

• Premolars : have a flattened surface and are used for grinding food into small pieces.

• Molars : are similar to premolars, but are larger. They are also used to grind food.

The teeth are coated with enamel it is the hardest substance in the body. Beneath the enamel is the dentine it is softer. The innermost portion of the tooth is called the pulp it contains blood vessels and nerves.

◉Tongue

The tongue is a sense organ that helps us taste food. We use the taste buds on the surface of the tongue to differentiate between sweet, bitter, salty and sour foods.

The tongue is a muscular organ that helps us mix food with saliva. It also helps us roll the chewed food into a ball or bolus which is pushed towards the back of the mouth where it is swallowed.

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☯Passing through the Oesophagus.

When the food is swallowed, a flap called the epiglottis prevents the food from entering the windpipe and choking the person. The swallowed food enters a long, muscular, pipe-like organ called the oesophagus that connects the An stomach to the mouth. The swallowed food travels to the stomach because of a wave-like motion in the walls of the oesophagus called peristalsis.

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☯Digestion in the Stomach

The stomach is a muscular organ that is found in the upper left side of the abdomen. The swallowed food stays in the stomach for around four hours.

• The walls of the stomach secrele digestive juices, acid and mucus.

• The digestive juices digest proteins in the food to simpler substances.

• The acid kills bacteria and other germs that are present in the swallowed food. It also helps the digestive enzymes to carry out their functions.

• The mucus coats the walls of the 24 stomach and prevents it from being digested by the digestive juices.

The walls of the stomach also contract and relax, thus helping to mix the digestive juices with the food. The food is made into a semi-solid called chyme which is then passed to the small intestine.

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☯Digestion and Absorption in the Small Intestine.

The small intestine is a long. narrow coiled tube that is around 7 metres long and found in the lower abdomen. The greater part of digestion and absorption takes place in the small intestine.

The walls of the small intestine secrete digestive juices. The liver secretes bile which it stores in the gall bladder Bile is released into the small intestine when needed.

• Bile breaks down fat into tiny droplets which can be easily acted on by the digestive juices.

• The digestive juices secreted by the walls of the small intestine break down fats into simpler substances that can be absorbed.

• The pancreatic juice breaks down starch into simple sugars, and proteins and fats into simple substances.

the small intestine also plays an important role in the absorption of the digested food into the blood stream. The inner walls of the small intestine have numerous projections called villi (singular. villus). The digested food enters the blood vessels in the villi through their thin walls.

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☯Absorption in the Large Intestine.

The large intestine is broader and shorter than the small intestine. It is around 1.5 metres long. The main function of the large intestine is to absorb water from the digested food. It also absorbs some vitamins and minerals.

The undigested food and waste is stored for a while in the rectum and sent out of the body through the anus. This process is called defecation.

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