Modes of Nutrition and Nutrition in human beings

Shyam Mohan June 13, 2022
Modes of Nutrition 
There are 5 modes of Nutrition 
1.Taking of Food (Ingestion)
2.Breakdown of complex food substances into smaller soluble food substances.(Digestion)
3.Digested Food is absorbed into body cells. (Absorption)
4.Absorbed food is use to provide energy or form new protoplasm. (Assimilation)
5.Removal of Waste Substances 

Nutrition in Human Beings 
Human Digestive System 
There are two parts of human Digestive System 
1.Alimentary Canal:- 
A long hollow tube which contains organs through which the food actually passes(Oesophagus,Stomach,Small Intestine,large Intestine etc.)
2.Accessory Organs:-Organs that helps in digestion but no foods passes through them.(liver, pancreas,salivary Gland etc.)

Mouth(Buccal Cavity)
  • Food is digested into mouth.
  • Food is crushed and chewed with the help of teeth.
  • Saliva moistens the food 
  • Tongue helps in mixing of food
  • Mouth has special glands that is knows as salivary gland.it secrets saliva.Saliva has a enzyme i.e, salivary amylase.Salivary Amylase converts complex sugars present in the food to simple sugars like Maltose. 
Oesophagus (food pipe)
  • Partially digested food moves into the food pipe.
  • When food enters in food pipe,walls of alimentary canals starts contraction and relaxation.Thus is known as Peristaltic Movement.
Stomach
  • Due to Peristaltic Movement food is pushed into Stomach.
  • It is muscular organ that is J shaped
  • Walls of stomach has "gastric gland".it secrets Gastric Juice that help in digestion.
Gastric Juice has three types of Enzyme 
  1. Pepsin:- It is enzyme those breakdown Protein.(Protein in Acidic Form)
  2. HCL:-.make the medium acidic 
  3. Mucus:- Protect inner line of the stomach from acidic medium 
After these process food go to Small Intestine.
Note:- Acidity is caused when enzyme by gastic juice make medium excessive acidic.So mucus becomes unable to protect inner lining of stomach.Small amount of acid passes into Stomach that caused acidity.

Liver
  • Liver is largest gland of the body.
  • Liver secrets bile juice.
  • Bile Juice stores in Gall Bladder.
  • After that Bile juice will go in the small intestine and perform two functions.
  •  (i)Make food alkaline
  • (ii)Emulastion of Fat
Emulastion of Fat:-it is process of breakdown large fat globules into tiny fat droplets.this is performed by bile salts.

Pancreas
  • It is cone shaped organ.
  • Pancreas secrets pancreatic juice.it contains three types of enzymes.
  • (i)Trypsin:-Tyrpsin Breaks Protein
  • (ii)Lipase:- Lipase breaks emulsified fat
  • (iii)Pancreatic Amylase:- it breaks Carbohydrates

Small Intestine 
  • Small intestine secrets Intestinal juice which do final digestion of food.
  • Intestinal Juice converts Carbohydrates into glucose,proteins into Amino Acids,Fats into Fatty Acid+Glycerols.
  • Digested food is absorbed by the walls of the intestine .Villi are finger like projections that is attached with the walls of small intestine.Villi increase surface area for better absorption.
 About Villi 
  • Villi are finger like projections that is attached by walls of small intestine
  • It increase surface area for better absorption 
  • Villi is coiled with blood vessels which take the absorbed food to each and every cell of the body.Food is utilised for obtaining energy,building up new tissues and the repair of old tissues.
Large Intestine(Colon) 
  • Undigested and unabsorbed food is sent into the large intestine.
  • Water will be absorbed in large intestine
  • Terminal portion of large intestine is known as rectum. At the end of rectum a core is present called anus.
Anus
  • The solid material is removed from the body via the anus.
  • Anus has a muscle called sphincter muscle which removes waste

Why Do Herbivores have longer small intestine then the Carnivores?
Ans:- the lengh of the small intestine differs in various animals depending on the food they eat.Herbioves need a longer small intestine to slow the cellulose(present in plant cell wall) to be digested.Meat is easier to digest,hence Carnivores like tigers have a shorter small Intestine.
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