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Regulating the

Regulating the. Internal Environment. homeostasis. Thermoregulation Osmoregulation Excretion. Regulators & Conformers. Regulation of Body Temperature. Transfer of heat by air or water movement. Emission of electromagnetic waves. Removal of heat from the surface of a liquid.

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Regulating the

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  1. Regulating the Internal Environment homeostasis • Thermoregulation • Osmoregulation • Excretion

  2. Regulators & Conformers

  3. Regulation of Body Temperature Transfer of heat by air or water movement Emission of electromagnetic waves Removal of heat from the surface of a liquid Direct transfer of heat

  4. Endotherms: High metabolic rate to maintain a high and very stable internal temperature Ectotherms: Low metabolic rate, body temperature determined by environment

  5. Thermoregulation • Adjusting the rate of heat exchange between the animal and its surroundings • Vasodilation/vasoconstriction • Countercurrent heat exchanger • Cooling by evaporative loss (skin, breathing) • Behavioral responses (basking, hibernation, migration) • Changing the rate of metabolic heat production (endotherms only)

  6. Countercurrent heat exchangers Bird legs Marine mammal flippers

  7. ENDOTHERMY • Shivering • Movement • Brown fat • Insulation (hair, fat, feathers) • Goose bumps • Vasoconstriction • Vasodilation • Blubber • Sweat glands • Panting

  8. FISHES • Most conformers • Endothermic fishes • circulatory adaptations

  9. Invertebratesaquatic – thermoconformers; terrestrial – behavioralendothermic – many flying insects

  10. Human Thermoregulation

  11. Torpor – physiological state (low activity) Hibernation – long term torpor (winter) Estivation – summer torpor

  12. WATER BALANCE & WASTE DISPOSAL Osmoregulation – management of body’s water content & solute composition Contractile vacuoles Transport epithelium – layer(s) of specialized cells that regulate solute movement move specific solutes in controlled amounts in particular directions joined by impermeable tight junctions forming a barrier at the tissue-environment boundary

  13. Salt secreting glands in marine birds Blood flow and salt flow counter current Note tight junctions in epithelium

  14. Nitrogenous wastes correlated to phylogeny & habitat Ammonia – very soluble, very toxic, aquatic species Urea – produced in the liver, land animals, less toxic, conserves water Uric acid – largely insoluble, excreted as semi solid paste, minimal water loss, birds & reptiles

  15. EXCRETORY SYSTEMS Filtration – pressure filtering body fluid, largely nonselective, produces filtrate Reabsorption – reclaims valuable substances by active transport Secretion – extraction of toxins & excess ions from blood Excretion – removal from body

  16. Flame-BulbSystem of a Planarian

  17. Metanephridia of an Earthworm

  18. Malpighian Tubules in Insects

  19. HUMAN EXCRETORY SYSTEM

  20. www.bioengineering.canterbury.ac.nz/graphics

  21. http://www.lakemichigancollege.edu/liberal/bio/anat/urin.htmlhttp://www.lakemichigancollege.edu/liberal/bio/anat/urin.html

  22. NEPHRON – functional unit of a kidney • Glomerulus – ball of capillaries, very porous • Bowman’s capsule – cup shaped swelling surrounding glomerulus • Filtration – blood pressure provides the force, nonselective: glucose, aa, salts, ions, urea, H2O etc. • Filtrate (essentially lymph) pathway – PCT, Loop of Henle, DCT, collecting duct • Cortical nephrons (cortex) – 80% of human’s • Juxtamedullary nephrons – extend into medulla • Blood vessels – afferent arteriole, efferent arteriole, peritubular capillaries, vasa recta

  23. Active Passive 1. PROXIMAL TUBULE • Reabsorption: • of salt (most imp) • Active or passive • Nutrients • Bicarbonate ions • Secretion: • H+ ions (pH) • Ammonia (pH) • Drugs, poisons Epithelium: Exterior side smaller surface area, minimizes leakage

  24. 2. DESCENDING LIMB - LOOP OF HENLE Active Passive Reabsorption of H2O continues Epithelium not very permeable to salts Interstitial fluid – osmolarity ↑ as fluid moves down from cortex to medulla

  25. 3. ASCENDING LIMB - LOOP OF HENLE Active Passive Transport epithelium permeable to salt NOT water Thin segment – passive Thick segment – active Filtrate becomes more dilute as it moves into cortex

  26. Active Passive 4. DISTAL TUBULE Secretion & reabsorption Regulation of: K+ (secretion) and NaCl (reabsorption) pH regulation (H+ & HCO3-)

  27. 5. COLLECTING DUCT Active Passive • Carries filtrate through medulla into pelvis • Actively reabsorbs NaCl • Epithelium (cortex) permeable to H2O but NOT salt, urea • High conc. of urea causes some to diffuse out

  28. Concentration of urine in the human kidney based on urea & salt

  29. Concentration of urine in the human kidney based on urea & salt

  30. Concentration of urine in the human kidney based on urea & salt

  31. REGULATION OF KIDNEY Antidiuretic hormone (ADH) – DCT & collecting duct Juxtaglomerular apparatus (JGA) – near afferent arteriole, responds to low blood pressure or volume Angiotensin II – activated by renin, constricts arterioles, reabsorption of NaCl in PCT, triggers release of aldosterone Aldosterone– adrenal medulla, DCT reabsorption of NaCl Renin-angiotensin-aldosterone system (RAAS) Atrial natriuretic factor(ANF) – oppose RAAS

  32. Hormonal control of the kidney by negative feedback circuits ADH enhances fluid retention by making the kidneys reclaim more water RAAS – JGA responds to in blood pressure/volume

  33. Vampire bat excretes • dilute urine while feeding (shedding weight for flight home) • concentrated urine while roosting

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