2. 1) Blood glucose concentration regulation Liver Pancreas (receptor) Liver Pancreas (receptor) Low blood glucose (stimulus) High blood glucose (stimulus) Normal blood glucose (norm) Secretes more insulin Secretes more glucagon glycogen  glucose glucose  glycogen negative feedback negative feedback

3. 2) Regulation of blood water potential (water Φ) Kidney tubules Pituitary gland (receptor) Kidney tubules Pituitary gland (receptor) water Φ increases water Φ decreases Normal water Φ (norm) secretes more ADH secretes less ADH  reabsorb less water  reabsorb more water negative feedback negative feedback hypothalamus hypothalamus stimulates stimulates causes causes

4. 3) Temperature regulation

5. Body hair

6. Why don’t we look like that?

7. The fuss about hair… Yu Zhenhuan (hairiest man in China) Austin powers

12. Structure of skin

14. Structure of human skin

15. Quiz

16. Label the parts below:

17. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

18. Microscopic skin slides

19. Microscopic skin slides

20. A. Epidermis

30. Structure of human skin (known as fat storage + insulating tissue) - secretes sebum (oily substance into hair follicle) 1) lubricates hair + keeps skin smooth & soft 2) prevents dehydration + has antiseptic action (prevents bacteria growth) - vasomotor nerves bring about vasodilation and vasoconstriction (helps regulate body temperature) - consists of nerve endings - sense pain, pressure/ temperature changes in external environment - sweat = mainly water + inorganic salts (NaCl) + metabolic waste product (urea) - sweat evaporation helps in temperature regulation - contraction causes hair to “stand on end”  responsible for goose bumps

31. Temperature Regulation

32. How do these mammals survive the cold?

34. 3) Temperature regulation – cold day Low body temperature Hypothalamus activated 1) vaso constriction 3) ↓ sweat production 4) shivering 5) metabolic rate ↑ Restore to normal temperature negative feedback 2) Dilation of of shunt vessels Temperature receptors in skin activated

35. Temperature regulation (summary) Normal body temperature hot cold Detected by temp. receptors (skin) Send nerve impulses to brain Brain sends impulses to relevant body parts 1) Blood vessels (constrict/dilate) 3) Sweat glands (active?) 4) Metabolic rate ( ↑ or ↓ ) 5) Hair erector muscles (relax/contract) negative feedback 2) Shunt vessels (Constrict/ Dilate) 6) Breathing rate increases? 7) Shivering?

36. Discuss as a group what you think would be some advantages of our bodies having a constant temperature