Fundamental Biology

 STRUCTURE OF TOOTH The human tooth is mainly divided into three regions 1. Crown 2. Neck 3. Root 1.Crown The crown is upper or covers the tooth. Crown is made up of enamel. Enamel is hardest substance of body. Below the enamel dentine is present. Dentine Dentine is made up of hard substance like bone. Dentine make major part of tooth. Pulp cavity Pulp cavity present inside the dentine. It's a jelly like part. It's supply with blood vessels,nerve fiber. 2. Neck It's short portion near the gumline. 3. Root It's surrounded by jaw bone. It holds tooth firmly in jaw bone. 𝩧𝩧ⅰⅰⅰⅰ Types of teeth categorised into Attachment - • Thecodont • Plerodont • Acrodont Sets of teeth - • Monophyodont • Diphyodont Shape of teeth - • Homodont • Heterodont

The process of digestion is accomplished(साध्य) by   mechanical   and   chemical processes . Buccal cavity M echanical processes The buccal cavity performs two major functions, masticationचर्वण of food and facilitationसुलभ of swallowingगिळणे. The teeth and the tongue with the help of saliva masticate and mix up the food thoroughlyपूर्णपणे.  Mucus in saliva helps in lubricating and adheringचिकट the masticated food particles into a bolusअन्नाचा गोल,गोळा. Pharynx & Oesophagus  The bolus is then conveyedपाठवणे, सुपूर्द into the pharynx and then into the oesophagus by swallowing or  deglutitionगिळणे .  The bolus further passes down through the oesophagus by successive waves of muscular contractions called  peristalsis .  The  gastro-oesophageal sphincter  controls the passage of food into the stomach. Chemical processes The saliva secreted into the oral cavity contains electrolytes (Na+, K+, CI-, HCO+) and enzymes -  salivary amylase  and  lysozyme .  The chemical process of digestion i