Animal Structure and Function

1. Animal Structure and Function Digestive Circulatory and Respiratory Excretory Nervous Muscular Endo, repro, develop Immune

2. DIGESTIVE SYSTEM

3. “tube within a tube” • This

4. “tube within a tube” • Develops from this

5. Coelom and germ layers

6. Don’t be grossed out but… ECTODERM DIGESTIVE TRACT (inside tube) MESODERM ENDODERM

7. Purpose for digestive system • To break down food into useable nutrients that can be absorbed and transported to cells throughout body • Remember – we are heterotrophs!

8. We need… • water, salts • Vitamins and minerals – to maintain overall health • Macromolecules • Carbs for energy • Proteins for building and repairing of tissues • Lipids for stored energy source, brain development (babies), essential for fat-soluble vitamins

11. ANATOMY- know pathway food travels

12. PHYSIOLOGY of human digestive tract • Two main parts • Alimentary canal – the tube or pathway that the food travels through • Accessory glands – outside of the “tube” but aid in digestion by secreting enzymes into the tract

13. Accessory glands • Fill in the enzymes they secrete as we go through the whole process • Salivary gland – • Pancreas – • Liver – • Gall bladder –

14. Oral Cavity – physical (teeth grinding) and chemical digestion (saliva) • Saliva = key enzyme is amylase which breaks down starch and glycogen into smaller carbs and maltose also contains: • mucin (glycoprotein to protect lining of mouth) • buffers and antibacterial agents

15. Pharynx • Pharynx – passageway for both air into lungs and food into esophagus • epiglottis – blocks trachea when swallowing so bolus (food ball) enters the esophagus

16. Esphagus • peristalsis starts here • bolus must pass through the esophageal sphincter

17. Stomach • gastric juice • pepsin • mucous

18. Small Intestines – the main player

19. Inside lining of Small Intestine MAJOR SURFACE AREA FOR MAJOR ABSORPTION!

20. Enzymes secreted into S.I.- you tell me their functions • pancreatic amylases from the pancreas • disaccharidases from the lining • trypsin and chymotrypsin from the pancreas • exopeptidases from intestinal lining • lipase from the pancreas http://www.biologyinmotion.com/bile/index.html • bile from the gall bladder

21. Control of pancreatic enzymes • Why secrete the inactive forms? • Trypsinogen • Chymostrypsinogen HINT: once activated they break down proteins and your tissues contain a lot of…

22. Asorption of nutrients in the small intestine • capillaries receive – carbohydrates and proteins • Nutrient rich blood from S.I. is carried via hepatic portal vessel to the liver • Liver is in charge of distributing nutrients to blood (and rest of body

23. Asorption of nutrients in the small intestine • Lacteals receive – packaged lipids • These lead to the lymphatic system which carries the lipids to the heart

24. Large Intestine • water reabsorption • salt excretion - if salt content is too high in blood • eliminate undigested food- feces formation and elimination

25. Large Intestine

26. Reclaiming Water in The L.I. • If lining of LI is infected with bacteria or virus – water unable to be reabsorbed so fecal material is watery = • diarrhea • If too much water is reabsorbed or sluggish peristalsis = • constipation

27. Radiological Images of GI Tract • http://www9.biostr.washington.edu/hubio511/RadAbdo/

28. Homeostasis and Control of Digestive System • Nervous system • Smelling, tasting and seeing (hearing the sizzle?) all stimulate the secretion of gastric juices

29. Negative feedback • Gastrin is secreted when food is present in the stomach • Gastrin increases the secretion of gastric juices • When the pH gets too low – gastrin secretion stops which in turn slows down gastric juice production (which caused the pH to lower in the first place)

30. Hormonal Control PANCREAS bicarbonate SECRETIN

31. Hormonal Control Bile Pancreatic Enzymes CCK

32. Comparative Physiology

33. HERBIVORE OR CARNIVORE?

34. Who’s GI Tract? Check text

35. The End! • Oh the pictures I could have put on this last slide!