Osmoregulation: The Basics Osmoregulation/Renal Physiology Osmoregulation: The Basics Balancing salt concentration (solute concentration) in the blood. Organisms can be osmoconformers Fresh Water: Salt Water: Organisms can be osmoregulators (240-450 mosm/liter) (humans optimum is 300mosm/liter) Water balance in cytoplasm…working for optimal conditions Cytoplasm Interstitial Fluid Blood (…and in kidney) Excretory System: handles nitrogenous waste Most organisms (vertebrates) have Kidneys to handle osmoregulation and excretion

Osmoregulation/Renal Physiology THE LIFE AQUATIC: opposing osmotic forces Marine Fishes: loss of water to hyperosmotic environment, balanced by drinking lots of water and active transport of Cl- out of body across gills. Produce very little urine. Freshwater Fishes: gain water from a hypoosmotic environment. Must actively transport Cl- into body across gills to maintain electrolyte levels. Excrete large amounts of dilute urine.

Osmoregulation/Renal Physiology THE LIFE TERRESTRIAL The threat of desiccation is perhaps the largest regulatory problem confronting terrestrial plants and animals. Human renal system works to maintain a blood osmolarity at 300 mosm/liter Humans can die with 12% water loss Dehydration is common: easy to see effects All animals loose water through respiration. Why? The human kidney (and kidneys of other terrestrial vertebrates) functions to remove nitrogenous waste, and also conserve water. Human kidneys produce a hyperosmotic urine.

Osmoregulation/Renal Physiology Nitrogenous Waste: A metabolic reality Why: Because animals often eat at 1° and 2° consumers…and they’re made of PROTEIN Ammonia: Fresh Water Fishes Aquatic Invertebrates Urea produced in liver Mammals, amphibians Uric Acid Insects, reptiles, birds

Cost/Benefits of different Nitrogenous Wastes Osmoregulation/Renal Physiology Cost/Benefits of different Nitrogenous Wastes Toxicity Dilution/Concentration Energetic Costs

Osmoregulation/Renal Physiology Cost/Benefits of different Nitrogenous Wastes Place ammonia, urea and uric on each of these spectra Toxicity Hi Lo Dilution/Concentration [Hi] [Lo] Energetic Costs Lo Hi

Osmoregulation/Renal Physiology Osmoregulation, carried out in the kidney is driven by the nephron: It has four essential functions.

Gross Anatomy of the Kidney Osmoregulation/Renal Physiology Gross Anatomy of the Kidney

The Low Down on Kidney Function Osmoregulation/Renal Physiology The Low Down on Kidney Function Organs of filtration, absorption and secretion Functional Unit is the NEPHRON (106/kidney) Only 10 cm long, but contain 80 km of tubule length (~ 50 miles) Only 1% of body mass, but receive 20% of resting cardiac output Filter 1,100 - 2,000 L blood/day Collect 180 L of filtrate Produce 1.5 L of urine (on a good day)

Nephrons: Millions of Tubules & Blood Vessels /Kidney Osmoregulation/Renal Physiology Nephrons: Millions of Tubules & Blood Vessels /Kidney Tubules Blood Vessels

A closer look at the Nephron Osmoregulation/Renal Physiology A closer look at the Nephron (look at how active transport of NaCl drives passive reabsorption “water chases the solutes”) ADH increases the Permiability of water Across the collecting Duct. When ADH is Blocked (by caffeine) You need to urinate more often.

Descending Loop of Henle: Permeable to… Osmoregulation/Renal Physiology Descending Loop of Henle: Permeable to… Transfer of Fluid from…

Ascending Loop of Henle Permeable to… Osmoregulation/Renal Physiology Ascending Loop of Henle Permeable to…

Descending Loop/ Ascending Loop/ Collecting Duct (permeable to… Osmoregulation/Renal Physiology Descending Loop/ Ascending Loop/ Collecting Duct (permeable to…

Osmoregulation: Water Budgets Osmoregulation/Renal Physiology Osmoregulation: Water Budgets

Osmoregulation with ADH Osmoregulation/Renal Physiology Osmoregulation with ADH Hypothalamus detects change in blood osmolarity (> 300 mosom/L) Release ADH, affects distal tubules and collecting ducts How… 300 mosm/L

Osmoregulation with RAAS Osmoregulation/Renal Physiology Osmoregulation with RAAS JGA = juxtaglomerular apparatus Responds to drop in BP JGA Renin Angiotensinogen Angiotensin II Adrenal Glands Arteries Aldosterone Vasoconstriction

Short term and Long term response to stress Osmoregulation/Renal Physiology Short term and Long term response to stress

Renal Function is tied to… Osmoregulation/Renal Physiology Renal Function is tied to… BLOOD.

Plasma: the liquid Matrix Osmoregulation/Renal Physiology Plasma: the liquid Matrix Muy Importante!

Osmoregulation/Renal Physiology The Suspended Cells

The Physiology of Blood Osmoregulation/Renal Physiology The Physiology of Blood RBCs and Hemoglobin… RBC production regulated by erythropoeitin… Luekocyte production: depends on what the body needs: associated with disease and infection, and inflammation 1st bullet : 2nd Bullet: 3rd Bullet:

Osmoregulation/Renal Physiology Blood Clotting: An enzymatic cascade Begins with injury, ends with Fibrin net

Renal Function is tied to… Osmoregulation/Renal Physiology Renal Function is tied to… EXCRETION (WASTE REMOVAL)

Physiological Connections Osmoregulation/Renal Physiology Physiological Connections Air pressure at sea level = 760 mmHg (O2 comprises 21% of air, hence 160 mmHg) Gases diffuse along a pressure gradient Differences are called Partial Pressures “Respiration happens passively by diffusion.” --Ron Carlson

CO2 Transport & Exchange Osmoregulation/Renal Physiology CO2 + H20 H2CO3 HCO3- + H+ CO2 Transport & Exchange

Oxygen Disassociation Curves Osmoregulation/Renal Physiology Oxygen Disassociation Curves Notice the steepness of the curve. As PO2 drops, Hb “dumps“ O2

Osmoregulation/Renal Physiology A few more terms Osmoconformer: Osmoregulator: Stenohaline: Euryhaline:

Invertebrate Excretory Systems Osmoregulation/Renal Physiology Invertebrate Excretory Systems

Marine Birds: Special Adaptations to xeric environment Osmoregulation/Renal Physiology Marine Birds: Special Adaptations to xeric environment