KNOWYOUR BODY-NAILS AND TEETH

Nails  are  part  of  our   toes  and fingertips.They  are  made  from hard keratin .Nails  grow  above  the fingertips, and  toes  in the form  of  dead cells,As  these   are dead  cells , their  cutting  does not cause bleeding  or pain.
Teeth  help  us  to  speak clearly.They  also  give shape  to  the  face.But the most  important  function  of teeth  is  the chewing  of food.When  a  baby  is about  six months  old  ,20  primary  teeth begin  to  erupt  .These  are called  milk  teeth.Children   lose  their milk  teeth  and  grow  another  at  the   age  of  six years, which  are  replaced   by  permanent  teeth.Most  of  the  adults  ,have   a set  of  32  teeth  by the  age of 20.Teeth  are  of  different  shapes  and they  do  different  things .Teeth   are fixed  into  our  jaws.A tooth   has  an  outside  hard  layer  of enamel.This  covers  the dentine.It  is  the hardest   substance  of  the body.But  it tend  to be  eroded  and destroyed   by  the acid  produced  in the mouth   during the breakdown  of food.We  need to  brush  our  teeth  daily, so  that  they  may not rot or decay.Human  beings  have  four kinds  of teeth.The incisors  for cutting  of food.The canines   are  for tearing  the food.The premolar and  molar  are for   grinding  and crushing  the food.The  Keratin  has  high  content  of sulfur.