Small intestines + Liver I

1. Nutrition in Mammals Chapter 6

2. Lesson recap

4. Stomach

5. Small intestines4. Adaptations of the intestines for absorption

7. Circular muscle contracts; lumen constricts Antagonistic muscles Longitudinal muscle relaxes

8. Demonstration

9. *Stomach Structure of Stomach Distensible = can stretch & expand Send “Full” signal to brain Numerous pits with gastric glands Pyloric splincter = ring of muscle connecting the small intestines.

11. Small Intestines – Last chance to digest!

12. Demonstration How does the movement of the intestinal wall look like?

13. How do villi help to increase rate of absorption in the small intestine? OR How does the villus structure help to increase rate of absorption in the small intestine?

14. Does surface area matter for absorption?

15. If the small intestines were only a hollow tube… 0.5m2 200.0m2

17. Lined with vili

18. Microvilli on villiAdaptation of the small intestines

19. How is the intestinal wall adapted for absorption?

21. Increased intestinal surface area 1 cell thick epithelium

22. Numerous capillaries to maintain concentration gradient Many capillaries carry substance away Each villus has a lacteal/lymphatic capillary surrounded by blood capillaries. Continuous transport of digested food substances away Adaptation of the small intestines

23. Q. How is Concentration gradient maintained at the site of the intestinal villus? A concentration gradient is maintained at the villus by the continual transport of digested food substances away from the villus. Adaptation of the small intestines

24. Absorption at the small intestines villus

25. Glucose & amino acids enter into blood capillaries via diffusion & active transport Glycerol & fatty acid diffuse into the epithelium, then combines back to fat moleculeswhen they enter lacteal Water & mineral salts also absorbed. How does absorption take place?

27. Stomach

28. Small intestines4. Adaptations of the intestines for absorption

29. Today’s Guest Mr. Liver

30. Q. How are food substances transported and utilized?Chapter 6 Pg 105

31. Liver Boss, I’m done with absorbing all the nutrients. My villus is rich. What do I do with them now? Good job! You’re done with all the goodies? Pass them to me and I’ll re-distribute!

32. But you’re quite a distance away, Can I send them to you by air mail? Huh? What is air-mail? There are no planes around the area. You need to ship the ‘goodies’ to me

33. Hepatic portal vein

34. Q. What are the ‘goodies’ to be transported? Glucose Amino acids

35. Fate of Glucose Redistributed Excess return So what do I do now with the excess glucose? Let’s check out for laborers in the market

36. In the Blood Market…. glucagon glucagon insulin insulin glucagon glucagon insulin

37. From pancreas…