DIGESTIVE SYSTEM PART 1 (NEET)

Digestive system

To perform various functions of the body energy is required which is obtained from food. The process of conversion of complex indiffusible food material into simple and diffusible food by mechanical and biochemical process is termed as digestion.

The alimentary canal is tubular structure which extends from mouth to anus . It develops from ectoderm and endoderm. 

Ectoderm - upto hard palate

Endoderm - from soft palate to rectum

Ectoderm - from anal canal to anus

The alimentary canal is divided into following parts 

1- mouth and buccopharynheal cavity

2) oesophagus

3) stomach

4) intestine - small and large

1) MOUTH AND BUCCOPHARYNHEAL CAVITY

Mouth is a horizontal transverse slit like aperture which is surrounded by upper and lower lip,a specific muscle is associated with lip called orbicularis oris muscle.

Serous gland are found on the inner part of lip . Serious gland is the modification of mucus glands. It's secretory substance is watery.

Mouth opens into buccopharynheal cavity this cavity is divided into two parts

1) Buccal vestibule the space between the gums and cheeks where the food is stored temporary for some time. It is a peripheral part. 

2) oral cavity - It is inner and central part which is surrounded by upper and lower jaw. Lined by stratified squamous epithelium. Upper jaw is fixed and lower jaw is movable. The roof of oral cavity is called as palate .