Digestive system

• Digestion is the breakdown of naturally occoccurring foodstuffs into diffusable form.
• • Enzymes play a key role in the digestion of food.
  • They are protiens.
• 4 characteristics of Enzyme.

  They are Destroyed by heating.

  They are substrate specific.

  Always forms the same end product.

  They act like a catalyst
• The digestive system consists of:

  1). alimentary canal

  2). Digestive glands
• The alimentary canal starts with the mouth and ends at the anus.
• Alimentary canal is 9 meters long and highly coiled in certain regions.
• There are 3 different types of salivary glands.
• What does the lips help in?

  They help in closing the mouth, sucking and sipping liquids, speaking.
• Function of the tongue.

  It helps in manipulating the food while chewing and mixing the food with the saliva, it also helps in swallowing, tasting and speaking.
• How many teeths do an adult human normally have?

  32 teeth.
• Mention the name of different types of teeth.

  1). Incisors

  2). Canines

  3). Premolars

  4). Molars
• Mention the function and the location of the teeth.

  1). Incisors : they are the 4 front teeth. Their function is to cut and bite the food.

  2). Canines : they are 1 on the either side of incisors. It's function is for holding and tearing the food.

  3). Premolars : they are 2, next to Canines, they are bicuspid. It's function is to grind and crush the food.

  4). Molars : they are the last 3 teeth. Their function is same as the premolars.
• The last molar in the jaw is called the wisdom tooth. Which appears in the age of 17-20.
• Teeth that are different in shape are called heterodont.
• Teeth that are of same shape are called homodont.
• The milk teeth have 20 teeth. They don't have premolars.
• The exposed part above the gum - crown
• The part that is embedded in a cuplike socket of the jaw bone - root.
• A slight constriction between the crown and the root - neck.
• The hardest substance in the body - Enamel.
• A part that is harder than the bone but not as hard as the enamel - Dentine.
• Mention the 3 different types of salivary glands and their location.

  1). PAROTID GLAND : located in the fornt and beneath each ear.

  2). SUB-MANDIBULAR GLAND : located in the inner side of the lower jaw.

  3). SUB-LINGUAL GLAND : located below the tongue
• Saliva has an enzyme called salivary amylase which breaks down starch into
• Functions of saliva

  1). It's lubricates the food.

  2). Acts as a solvent.

  3). Helps to form bolus.

  4). It cleans the mouth
• Oesophagus has a special movement called Peristalsis which is a rhythmic contraction of circular muscles to help the food pass through the oesophagus
• 1). The opening of the stomach into the intestine - pyloric sphincter

  2). The opening between the Oesophagus and stomach - cardiac sphincter

  3). The juice released by the stomach - Gastric juice.

  4). The food that attains a pulp like form - Chyme
• 3 parts of the small intestine

  1). Duodenum

  2). Jejunum

  3). Ileum
• Short note on Bile juice.

  It's a yellowish-green and watery fluid which is produced in the liver, it's transported through the hepatic duct. The bile juice has sodium bicarbonate.
• Mention the 3 parts of large intestine.

  1). Caecum

  2). Colon

  3). Rectum
• The large intestine absorbs water from chyme.
• Assimilation is the conversation of the absorbed digested food into body material.
• The liver is the largest gland in the body and it's located in the upper right side of the abdomen just below the diaphragm.