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Ashiq wazir digestive presntion+.ppt

  1. co12 - Characteristics Of Life: C. = Cells H. = Homeostasis – Maintain Balance A. = Adapt to environment R. = Reproduce G. = Grow and develop E. = Run energy transformations R. = Respond - For organisms to grow, repair themselves, fuel their cells, reproduce, and undergo cell division; they must acquire building blocks and energy-rich molecules from their environment.
  2. 12-2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. INGESTION – Act of taking in food and drink into body DIGESTION BREAKDOWN – Chemical and Physical ABSORPTION – Nutrient molecules absorbed from gut into bloodstream ELIMINATION – Ridding the body of undigested food waste
  3. During Mechanical digestion food is broken down to create more surface. Food is mushed up and broken apart. Example. Chewing with teeth or churning food in stomach. No new molecules are produced!
  4. During Chemical digestion food molecules are broken down by enzymes to produce brand new smaller molecules. This requires digestive enzymes and water as a substrate to run these hydrolysis reactions.
  5. In many parts of the digestive tract both types of digestion are happening simultaneously. For example: in the stomach.
  6. Fig. 12.1 Our goal today is to get more familiar with the anatomy (parts) and physiology (function) of the digestive tract.
  7. Fig. 12.2a The mouth is a good starting point: different teeth have different functions
  8. Fig. 12.2b Two main regions of a tooth
  9. 12-9 • Tonsils at the back sides of the mouth protect against infections. • Tonsillitis results when the tonsils become inflamed; the infection can spread to the middle ears. • Three pairs of salivary glands (parotid, sublingual, submandibular) send saliva (containing salivary amylase for digestion of starch to maltose) into the mouth.
  10. Fig. 12.3 During swallowing, we need to prevent food from going up into the nasopharynx or into the trachea.
  11. Fig. 12.4 Why do you think that it is important that the digestive tract is lubricated on both the inside (mucosa puts out mucus) as well as on the outside (serosa puts out lubricant)?
  12. 12-12 • The esophagus is a muscular tube that conducts food through the thoracic cavity and diaphragm into the stomach. • Peristalsis begins in the esophagus; this collapsed tube moves the bolus of food downward after swallowing occurs. • Heartburn is a burning pain when acidic stomach contents enter the esophagus.
  13. Fig. 12.5
  14. 1. Storage of a meal – most expanded structure along the alimentary canal
  15. 2. Mechanical Digestion of food – Stomach is very muscular and it squeezes to churn and mix food to physically break it down
  16. 3. Chemical Digestion of food – Adds PEPSIN enzyme to start chemically breaking proteins into small peptide chains
  17. 4. Protection against Germs – HCl (acid) helps activate enzymes but it also helps kill many of the bacteria that we ingest.
  18. Fig. 12.6
  19. The Duodenum is only about 45 cm (18 inches long) but it plays a couple of very important roles: 1. Receives incoming Stomach Chyme, Pancreatic Juices and Bile from Liver and Gall bladder. 2. Secretes digestive juces/enzymes from duodenal glands
  20. 1. Receives undigested waste and helps absorb fluid from those wastes back into the bloodstream, to help keep us from dehydrating 2. Helps compact and form feces. 3. Harbours helpful bacteria which can further break down wastes to free up minerals and some bacteria will help produce and free up some vitamins, such as Vitamin K