1 / 21

We have learnt…

We have learnt…. What are the 4 stages of nutrition? Why must we digest our food? What are the two types of digestion? What is the structure and function of: Mouth Oesophagus. Question 1. What is the enzyme that is produced by the mouth? Protease Lipase Amylase Cellulase. Question 2.

novia
Download Presentation

We have learnt…

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. We have learnt… • What are the 4 stages of nutrition? • Why must we digest our food? • What are the two types of digestion? • What is the structure and function of: • Mouth • Oesophagus

  2. Question 1 What is the enzyme that is produced by the mouth? • Protease • Lipase • Amylase • Cellulase

  3. Question 2 What is the process of moving food down the oesophagus • By gravity • Absorption • Excretion • Peristalsis

  4. Question 3 Digestion is present in the oesophagus. True/False

  5. Question 4 Which of the following is not one of the stages of holozoic nutrition? • Absorption • Egestion • Ingestion • Digestion

  6. Lesson Objective • Describe the structure and the main functions of the stomach in relation to digestion. • Holiday Assignment

  7. The Stomach

  8. Stomach : Structure • Thick muscular bag with thick muscle walls • At the end of the stomach, there is a muscular valve called pyloric sphincter • Controls the entry of food from the stomach into the intestines

  9. Stomach : Functions • Mechanical Digestion • Peristalsisin the stomach helps to mix and churn the food • Digestion of proteins. • Storageof food, where the partly digested food particles becomes liquefied chyme.

  10. Stomach : Functions Protein digestion begins in the stomach • Proteins  polypeptides • Protein digestion in the stomach requires the gastric juice • Food in the stomach stimulates the gastric glands to secrete gastric juice

  11. Gastric Juice • Gastric juice is a dilute solution of: • Hydrochloric acid (~pH 2) • Pepsin • Rennin Gastric Juice

  12. Stomach : Functions Functions of dilute HCl: • Denatures salivary amylase • Activatesinactive enzyme, Pepsin • Provide slightly acidic for action of gastric enzymes • Kills potentially harmful microorganisms

  13. Stomach : Functions Pepsin (protease) • Digest proteins into polypeptides proteins polypeptides pepsin Pepsin does not digest proteins to amino acids!

  14. Stomach : Functions • Function of Rennin (for your information): Rennin curdles milk proteins • converts the soluble caseinogen found in milk to insoluble casein • caseinogen (soluble) casein (insoluble) • this process requires Ca2+ • This allows the insoluble casein to remain in the stomach long enough for digestion by pepsin.

  15. Summary • Stomach • Structure • Functions Mechanical Digestion Chemical Digestion • Hydrochloric acid (~pH 2) • Pepsin • Rennin

  16. Remember your job application? Let us assess without you will get the job!

  17. Mouth Applying for job : Digestion of Starch Condition: pH 7 Skills: • Tongue • Teeth • Saliva

  18. Stomach • Applying for job: Digestion of protein • Condition: pH2 • Skills: • Mechanical Digestion • Chemical Digestion (Gastric Juice) • Hydrochloric acid • Pepsin • Rennin

  19. Holiday Assignment • Ten Years Series Questions • Watch animation and complete the worksheet

More Related