Water and Electrolyte Balance in Animals Terrestrial animals like this cheetah lose water every time they breathe and urinate! Drinking is an important way to gain water and maintain homeostasis! Chemical reactions of life happen inside of water! Humans can survive for weeks without eating, but only for 3 days without water. Water balance is achieved when water intake = water loss

Review: Types of Transport Diffusion = movement of substances from high concentration to low cocnentration

Review: Types of Transport Diffusion = movement of substances from high concentration to low cocnentration

Review: Types of Solution Diffusion = movement of substances from high concentration to low cocnentration

Osmoregulation Osmoconformers = Osmostic stress = when the concentration of dissolved substances in a cell or tissue is abnormal; osmoregulation is the process by which living organisms control the concentration of salt and water in their bodies; tissues are isotonic with respect to seawater

Osmotic Stress in Seawater Hypertonic environment Osmoregulators = Hypertonic environment Osmoregulators = fish that actively regulate osmolarity;hypotonic relative to environment; water flows out of gills by osmosis  drink large quantities of seawater; drinking large amounts of water throws off electrolyte balance; have to actively pump out excess ions

Osmotic Stress in Freshwater Hypotonic environment

Osmotic Stress in Freshwater: Salmon Chloride Cells have membrane proteins that can “flip”

Osmotic Stress on Land: Insects

Osmotic Stress on Land: Insects Ability to close spiracles; spiracles located on underside of abdomen; waxy cuticle outer layer of exoskeleton

Types of Nitrogenous Wastes NH3 (ammonia) NH4+ (ammonium ion) TOXIC!

Ammonia Urea Uric Acid Image Solubility Toxicity Water Loss Energy Loss Organisms NH3 (ammonia)

The Master of Osmoregulation: The Vertebrate Kidney Cortex; medulla; most of kidney’s mass is made up of small structures called nephrons  over 1 million nephrons in each kidney!

A nephron; bowman’s capsule and glomerulus (ball of yarn) form a structure called the renal corpuscle

Renal Corpuscle: Filtration by Size Water and small solutes (electrolytes) pass through pores; proteins, blood cells and other large components of blood do not. Blood pressure supplies the force for filtration; strains large volumes of blood without any ATP needed; form a filtrate  about 25% of water and solutes present in blood is removed  capable of producing 180 liters of filtrate per day; about 99% is recycled

Reabsorption: The Proximal Tubule Active Transport via Protein Pumps

Reabsorption: The Loop of Henle Creating an Osmotic Gradient

Predict what happens to the osmotic gradient when the drug flurosemide inhibits membrane proteins that pump sodium and chloride ions out of the thick ascending limb.

Tight Control via Hormones The Collecting Duct: Tight Control via Hormones ADH =

What impact will this have on an individual? Alcohol inhibits AHD  What impact will this have on an individual? Nicotine stimulates ADH release What impact will this have on individual?

What impact will this have on an individual? Alcohol inhibits AHD  What impact will this have on an individual? Nicotine stimulates ADH release What impact will this have on individual?

Tight Control via Hormones The Collecting Duct: Tight Control via Hormones Aldosterone = Low blood volume: Sodium re-absorption increases, water follows; blood volume restored