Unit 2A Human Form & Function

1. Unit 2AHuman Form & Function Body systems The digestive system

2. Study Guide Read: • Text page 87- 98 Complete: • RQ 5-13 • AYK 1-8

3. Digestion • Digestive processes can be chemical (involving digestive enzymes), or mechanical. • Chemical digestion the breaking down of the nutrients we eat into simpler organic compounds that can be absorbed by the body. • Mechanical digestion is the breaking down of large sized food to smaller sized food.

5. The anatomy of the digestive system US Govt NIH

6. Structure of the alimentary tube Villus Mucosa Thin muscle layer Submucosa Longitudinal muscle layer Circular muscle layer Peritoneum

7. Chemical digestion in the mouth

8. The salivary glands Parotid gland Submandibular gland Sublingual gland

9. Section through the head Nasal cavity Palate Teeth Tongue Pharynx Epiglottis Hyoid bone Vocal cords Larynx Esophagus The Miles Kelly Art library, Wellcome Images

10. The tongue Jari Keinänen

11. Mechanical processes in the mouth • Chewing (mastication) • Bolus formation • Swallowing

12. Human teeth are generalised – they can process both meat and fibrous plant foods Incisor teeth Canine tooth Premolar and molar teeth The Miles Kelly Art library, Wellcome Images

13. Human dentition Pre-molars Molars Incisors Canine Gray’s Anatomy

14. Tooth section Enamel Dentine Crown Pulp cavity Gum Neck Cementum Root canal Root The Miles Kelly Art library, Wellcome Images

15. Swallowing and peristalsis Epiglottis closes entrance to windpipe Tongue pushes bolus into throat Peristalsis carries bolus into stomach The Miles Kelly Art library, Wellcome Images

16. Peristalsis Wave-like contraction of the muscular wall travels along the gut BOLUS

17. Chemical digestion in the stomach

18. Mechanical processes in the stomach • Muscular churning mixes food with gastric juices (forms chyme) • Rennin (in infants only) curdles milk

19. Absorption in the stomach • Limited absorption of water, glucose, alcohol and some drugs takes place in the stomach.

20. Section through the stomach Fundus Esophagus Rugae Pyloric sphincter muscle G Meyer ANHB – UWA

21. Section through the stomach Esophagus Three muscle layers Rugae Pyloric sphincter muscle Duodenum

22. Chemical digestion in the duodenum

23. Mechanical processes in the duodenum • Bile salts emulsify fats (reduce them to small droplets which increases their surface area).

24. Inside the duodenum

25. Chemical digestion in the small intestine

26. Absorption in the small intestine • Glucose, amino acids, water and minerals are absorbed into the blood capillaries. • Fatty acids and glycerol are absorbed into the lacteals (forming chyle).

27. Section through small intestine showing villi Secretory cells Villus Gland L. Slomianka ANHB-UWA

28. Section through a villus Epithelial cells & goblet cells Lacteal Network of blood capillaries Intestinal gland Lymph vessels

29. Functions of the large intestine • Further absorption of water and some salts. • Bacterial activity – there are trillions of resident bacteria in the large intestine. They are believed to have several important roles in addition to digesting cellulose in plant foods and synthesising some vitamins (e.g. folic acid).

30. The large intestine LIVER Colon(transverse branch) Colon(ascending branch) Caecum Colon(descending branch) Appendix Rectum

31. Some major functions of the liver • Deaminates amino acids • Converts glucose to glycogen • Produces bile • Stores iron, and vitamins A, B12, D, E & K • Synthesises vitamin A & plasma proteins • Detoxifies drugs (including alcohol) and other toxins.

32. Liver Stomach Pancreas Wellcome Photo Library

33. External features of the liver Inferior vena cava Hepatic artery Gall bladder Bile duct Hepatic portal vein Miles Kelly Art Library

34. Liver lobule Artery, vein & bile duct Central vein Lobule L. Slomianka ANHB-UWA