Digestion and Absorption Class 12 NEET Notes

DIGESTION AND ABSORPTION CLASS 12 NEET NOTES

  • Carbohydrates, proteins and fats are major components of our food
  • Vitamins and minerals also required in small quantities
  • Food provides energy and organic materials for growth and repair of tissues

WHAT IS DIGESTION?

  • Conversion of complex food substances into simple absorbable substances is called digestion.
  • Animals exhibit holozoic nutrition, i.e. animals eat food which cannot be used by the cells directly; hence, food is digested first.
  • Our digestive system applies both mechanical and biochemical methods for digestion

HUMAN DIGESTIVE SYSTEM

Human digestive system consists of I) Alimentary Canal II) Digestive Glands

I) ALIMENTARY CANAL

  • The alimentary canal is a 6–9-metre long tube varying in diameter.
  • It extends from the mouth to the anus and consists of Mouth, Oral Cavity, Pharynx, Esophagus, Stomach, Small intestine, Large intestine and Anus

MOUTH

  • Anterior opening of the alimentary canal
  • Bounded by two soft & movable lips
  • Intake of food
  • Leads to the buccal cavity

BUCCAL CAVITY OR ORAL CAVITY

  • First cavity of the alimentary canal
  • Oral cavity consists of:
    • Upper part – Palate
    • Lower part – Teeth & Tongue
  • Vestibule is space between buccal cavity and lips
Palate:
  • Palate is roof of buccal cavity
  • Palate has two parts i) Hard palate ii) Soft Palate

Hard palate:

  • Bony due to maxilla & palatine bones
  • Has palatine Rugae
  • Rugae most developed in carnivores

Soft palate:

  • Soft & Cartilage
  • End of soft palate hanging structure is uvula
  • Uvula help to close internal opening of Nasal chamber

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About the Author: Rajkumar

Rajkumar is a lecturer from TamilNadu, India. He holds a master degree in botany. Passionate, Blogger, Video Creator, Photography. He helps the students for advancement and provide Biology Materials. Life Motto: Live while you can! Teach and inspire while you could & smile while you have teeth

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