Excretion to external environment (through kidneys, lungs, gills,

1. Excretion to external environment (through kidneys, lungs, gills, digestive tract, or body surface, e.g., sweat, tears, sloughed skin) Input from external environment (through ingestion, inhalation, absorption through body surface, or artificial injection) Storage depots within body (no function other than storage) Metabolically produced by body Metabolically consumed in body (irretrievably altered) Inputs to internal pool Outputs from internal pool (Inside body) Internal pool (extracellular fluid concentration) of a substance Reversible incorporation into more complex molecular structures (fulfills a specific function) Fig. 13-1, p.573

2. Fig. 13-2, p.574

3. Table 13-1, p.575

4. Difference between ECF and ICF • Cellular proteins • Cellular organic osmolytes • Unequal distribution of Na+ and K+

5. Fig. 13-3, p.576

6. Osmotic and volume balance Osmotic problems threaten cells and animals • Evaporation of body water into air (eg. sweating or breathing) • Osmosis into or out of environment (eg. fresh water or saline water) • Freezing (locks up water in ice crystals and concentrates ions in unfrozen water) • Excretion (require water for waste removal) • Diseases (eg. Diabetes)

7. Fig. 13-4a, p.577

8. Fig. 13-4c, p.577

9. Fig. 13-5, p.578

10. Fig. 13-6, p.579

11. Fig. 13-7, p.579

12. Table 13-2a, p.580

13. Table 13-2b, p.580

14. Table 13-2c, p.581

15. Fig. 13-8, p.582

16. Fig. 13-10, p.585

17. Medium <5 mOsm Absorbs water through gills and skin Body fluids ca. 300 mOsm Obtains salts through “chloride” cells in gills and with food Removes much water and some salt via dilute urine Salts lost via feces Fig. 13-11, p.586

18. Adaptation of Freshwater Animals • Active transport of ions • Hypotonic urine • Lower internal osmolarities • Low permeability of integument

19. Terrestrial animals Dietary H2O NaCI H2O retention H2O lost via respiration NaCI retention H2O NaCI lost via excretion Fig. 13-12, p.587

20. ECF Hypertonicity • Insufficient water intake (eg. Drought, desert) • Excessive water loss (heavy sweating, panting, vomiting, diarrhea, diabetes, breath in dry air, exposed to salt water) • Drinking hypertonic saline water • Alcohol inhibits vasopressin secretion

21. ECF Hypotonicity 1. Intake of relatively more water than solutes 2. Retention of excess water without solute

22. Table 13-3, p.590

23. ECF volume Relieves Osmolarity Arterial blood pressure Relieves Relieves + + Hypothalamic osmoreceptors (dominant factor controlling thirst and vasopressin secretion) Left atrial volume receptors (important only in large changes in plasma volume/arterial pressure) + + Thirst Vasopressin Arteriolar vasoconstriction H2O intake H2O permeability of distal and collecting tubules Plasma osmolarity Plasma volume Hypothalamic neurons H2O reabsorption Urine output Fig. 13-13, p.591

24. Table 13-4, p.592

25. Na+ load in body Arterial blood pressure a b GFR Aldosterone Na+ filtered Na+ reabsorbed Excretion of Na+ and accompanying Cl2 and fluid Conservation of NaCl and accompanying fluid Fig. 13-14, p.593

26. Fig. 13-15, p.594

27. Fig. 13-16, p.596

28. Fig. 13-17, p.596

29. Three pH defenders and Four pH buffer systems • Three defense against pH changes • Chemical buffer systems • Respiratory control • Excretory control

30. Fig. 13-19, p.599

31. Three pH defenders and Four pH buffer systems • Four buffer systems • Carbon dioxide-bicarbonate buffer • Peptide and protein buffer • Hemoglobin buffer • Phosphate buffer

32. p.600

33. H+ secretion HCO3– conservation H+ excretion HCO3– excretion Plasma [H+] Plasma [HCO3–] Plasma [H+] (or plasma [CO2]) Fig. 13-20, p.603

34. Fig. 13-23, p.606