Digestive system

• The digestive system is responsible for breaking down food into nutrients that can be absorbed by the body.
• Digestion begins in the mouth with mechanical breakdown through chewing, followed by chemical breakdown through enzymatic action.
• Where does the digestive system take place

  mouth, stomach, and small intestine
• Carbohydrates


  • Starch is the principal carbohydrate ingested by humans
• Fats


  • Function as principal energy reserve
  • Triglycerides as the richest energy source
  • Have a greater capacity to combine with oxygen and consequently have a higher heat content
• The liver is the principal organ responsible for the degradation and synthesis of amino acids
• The amino acids synthesized in the liver and the amino acids obtained from protein digestion are transported by the blood to all the tissues of the body
• What are the factors aiding in digestion

  • Enzymes
  • Cooking
  • Mastification
  • Auto-digestion
• Their role is to change the macromolecules to simpler molecules that are now absorbable in our body

  Enzymes
• make the molecules partially hydrolyzed thereby making the molecules more readily digestible. Also, cooking improves the flavors, thus stimulating the secretion of digestive juices

  Cooking
• breaking down the size of the particles present greater surface area of the particles for the action of the digestive juices and therefore enhances digestion

  Mastication
• ripening of fruits, maturation of vegetables with accompanying changes in taste and consistency are all secondary aid to digestion

  auto-digestion
• made up of about 99.3% water and 0.7% solid. 


  saliva
• The solid of the salive is made up of _______ organic and ______ inorganic

  0.5%;0.2%
• The organic constituents of saliva are


  mucin, albumin, globulin, ptyalin, maltase, urea, cholesterol, phospholipids
• What are the inorganic constituents of saliva are

  calcium phosphate and carbonate
• What makes saliva digestive

  ptyalin
• facilitates swallowing due to the lubricating effect of __________?

  mucin
• Saliva is _______ for soluble substances

  Solvent
• Saliva _______ for irritant substances like acids and alkalies

  diluent
• In Gastric Juice, the solids are the organic constituents like the mucin, enzymes pepsin, rennin and lipase


  mucin, enzymes pepsin, rennin and lipase
• the inorganic components of gastric juices are the 


  KCl, earthly phosphates, NaCl, etc
• The pancreatic juice secreted to the amount of about

  500ml
• What is the pH of pancreatic juice

  pH 8
• What are some important solid constituents of pancreatic juices 


  trypsin, chymotrypsin, amylopsin, and steapsin
• made up of 98.5% water and around 1.5% solid

  pancreatic juice
• What are some enzymes in intestinal juice 


  sucrase, maltase, and lactase
• muscular baglike organ that continues mechanical and chemical digestion


  Stomach
• chemical digestion is finished here, food has been broken down into nutrients, which are absorbed into the blood


  Small instestine
• main job is to absorb water fromundigested food  mass

  Large intestine
• • undigested materials become solid waste which is stored in the ________ and is expelled through the _______

  Rectum; anus
• muscular organ uses peristalsis: wavelike movement to squeeze food to stomach

  Esophagus
• _______ is a powerful mixture of hydrochloric acid and enzymes like pepsin.

  Gastric juice
• breaks down proteins and creates an acidic environment that kills bacteria that might be present in food

  Hydrochloric acid
• further breaks down proteins into smaller peptides.

  Pepsin
• Produced by the pancreas

  Pancreatic Juice
• • Further breaks down carbohydrates into simple sugars.

  Amylase
• • Breaks down fats into fatty acids and glycerol.

  Lipase
• • Break down proteins into amino acids.


  Trypsin and chymotrypsin
• Where is bile secreted 


  Bile