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The   Brain  is  the  Major  Organ  of  the  central  nervous  system and the control  centre  for all the    body's  voluntary   and  in voluntary  activities.It  is  also  responsible   for  the complexities  of thought,memory,emotion,and language.In  adults  ,this  complex  organ  is  a  mere  1.4  kg  in weight.Containing  over 10  thousand  million  nerve cells Three  distinct  regions  can  be  seen -the  brain stem,the cerebellum, and  the large  cerebrum.The  brain stem  controls   the vital  body functions,such as breathing  and digestion.The   cerebellum's  main  functions  are  the maintenance  of  posture, and  the  coordination  of  body  movements.The  cerebrum      which  consist  of   the right  and left  cerebral  hemisphere. joined   by    the corpus    callosum, is  the  site  of most  conscious    and intelligent  activities.  

The  Spine  or vertebral,column has  two  main  functions;it serve  as a  protective  surrounding  for  the delicate  spinal  cord. and form the  supporting   back  bone of the Skeleton .The spine consist  of 24   separate   differently  shaped  bones vertebrae  with  a curved  ,triangular  bone the sacrum at the  bottom.The  sacrum  is made up  of  fused  vertebrae  ; at  the  lower  end   is  a  small  tail  like  structure  made up  of tiny  bones ,collectively  called  the coccyx.Between  each pair  of vertebrae  is a disk  of cartilage  that cushions  the  bones during the movement.The  top  two  vertebrae differ  in  appearance  from  the others  and works  as a pair ;the  first  called  the atlas ,rotates   around  a stout vertical  peg  on  the second,the axis.This arrangement  allows  the skull  to  move freely up  and down, and from side to side.

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

We  need  energy to  do our  daily works.We  get  this  energy  from  the  food  that  we eat.When  we eat  ,teeth  help  in breaking the food  into pieces  ,and then    in our digestive  system,the  pulp   passes through  the stomach and  intestines.The useful  digested  food passes  through  the  intestine   into  the   blood,to  liver,and the  waste   products  are pushed  out of the body. That useful   digested  food is converted   into  energy   that  help  us in working.All  kinds  of food help  in  giving energy  to  the body.Balanced diet  play a very  important  role in giving  an appropriate amount  of energy   to the body.A   Balanced  diet  is  that  which  include a sufficient  amount  of all necessary nutrients like carbohydrate,protein,Minerals,water, fats etc.90%  of  our energy  comes from  fossil   fuels.The  main  source  of energy  is the sun  ,Plant make  their food   with  the help  of  the sunlight.  

The   Urogenital  system  mainly  related  to two  types  of functions.One  is related  to  the  kidneys that maintain  the  volume and  composition   of  body fluids   within   very  narrow  limits.Second  is related  to   the sex organs that facilitates  reproduction.Kidneys  help  in maintaining   the body's  internal   environment   in  physiological   state.A  healthy  kidney performs  regulation  of  water   in  the body, maintains normal acid  /base equilibrium,eliminates metabolic waste products  and also  maintains  the retention  of  vital  substances.The   is why  the kidney  receives   the  one  quarter  of the  cardiac   output  which  is  about  1.3 liters per minute.Eventually,only   about  1 percent of the  original volume  is passed   down  the ureter  to  the bladder  reservoir  for discharge.The  kidney filter 180 quarter of blood   daily.1/4  of all the blood  in human  body is filtered   by the kidney every minute.The yellow  colour  of the urine  is caused 

We   need food  to keep  us alive.What happens  to that food  inside our body? The process from  the moment  the food enter the mouth until  it mixes  into blood stream is called  digestion.Digestion  usually  takes up  to 18 hours.There are about  8 meters  of tubes and chambers inside our body that process  the food eaten by us.It consist of organs that  help in chewing ,swallowing,breakdown and absorption   of food as well as expulsion  from the body of what is left afer  the process.In  the mouth the  tongue and teeth  helps   in  breaking of food  .Then  this  bolus  is transferred  to the stomach after we swallow  it. Gastric juce in  the  stomach  ,is rich  in  hydrocloric  acid  and the protein-spilitting  enzyme  pepsin.Then  food reaches Duodenum through  a muscular   valve.The   pancreatic juce contains  enzymes for splitting  carbohydrate,protein and fat  in  the  food.Bile  a bitter liquid  in the liver  also   help  in this process.This  useful  digested  food  passes 

A human nose  can distinguish around  4000 different  substances.We  use our nose  to breathe  and to smell.We can differentiate  the god and bad odor.Smell  floats in the air.We smell  things  we take in air  through  our noses.The sensory cells  in the nose,detect the smell and send message to the brain.Our sense  of smell  also  help  our sense of taste.So, our sense of smell and taste are  closely linked. Our tongue  receptors   differentiate  only four  types of taste qualities; sweet,sour,salt,and bitter.There  are thousands  of taste  buds all over  the tongue.These   survive  only for a matter of days  under go  rapid and continuous   replacement.Each  taste  bud  consist  of  sensory  cells  that  are  connected    to  the mid brain through taste  fibers.The  sensors  send  massage  to  the  brain about what we  are  eating.The  front  of the tongue  taste  sweet things,the sides of the tongue  taste  salty  and sour things.The back  of the tongue  tastes bitter  things.The