Page 406 - General Knowledge

GENERAL KNOWLEDGE 2019

Molars - for chewing and grinding.
 Cheek teeth – Both premolars and molars.
 Milk teeth do not include molar teeth.
 In humans, first set of teeth come in between 6-8 months.

 Enamel is the hardest part of teeth.
 Tusks are the incisors of upper jaw in elephants.
 Among mammals, horse and pig have maximum number of teeth.
Tongue
 Saliva secreted by salivary glands.
 It is mixed with the chewed food by the tongue.
 Tongue contains taste buds that sense bitter, sour, salty or sweet taste.
Functions of digestive system
 Splitting of complex food materials into simple molecules by hydrolysis to generate energy.
 Main function is to easily absorb by intestine.
 Man and other animals have holozoic nutrition.
Digestion of Food

Digestion in Mouth
 Salivary amylase acts on starch in mouth.
 Starch (complex form) is converted into maltose (simple form) via ptyalin.
Digestion in Stomach
 Food passes down through oesophagus into stomach.
 Pepsin digests proteins and converted into peptones.

 Renin converts milk into curd.
 Chyme – Digestion food is now known as Chyme.
Digestion Process

Ingestion of food

 Takes place in buccal cavity.
 Salivary glands have starch splitting enzyme Ptyalin.
 Parotid gland – Largest salivary gland.
Digestion in Duodenum
 Chyme moves to duodenum.
 Food mixed with liver to breakdown fast into smaller globules.
 Amylase – Converts starch into sugar.
 Lipase – Converts fats into fatty acids and glycerol.
Digestion in Intestine
 Food passes in to ileum, mixed with intestinal juice.
 Maltase – converts maltose into glucose.
 Lactase – converts lactose into glucose and galactose.
 Sucrase – converts sucrose into glucose and fructose.
Ejection of unwanted food
 Digested food - Passes into large intestine.
 Large intestine cannot absorb food, but absorbs water.

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