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Wringing out a washcloth in Space!. CSA Astronaut Chris Hadfield performed a simple science experiment designed by grade 10 Lockview High School students Kendra Lemke and Meredith Faulkner: http://www.youtube.com/watch?v=o8TssbmY-GM&feature=player_embedded.
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Wringing out a washcloth in Space! • CSA Astronaut Chris Hadfield performed a simple science experiment designed by grade 10 Lockview High School students Kendra Lemke and Meredith Faulkner: http://www.youtube.com/watch?v=o8TssbmY-GM&feature=player_embedded
Osmotic Pressure • A measure of the tendency of water to move into a solution. • The more dissolved particles in a solution, the higher the osmotic pressure of that solution. • Since blood contains many large protein molecules, the osmotic pressure of blood should be higher than in the extracellular fluid. If it’s too high, body cells suffer dehydration.
Antidiuretic Hormone (ADH) • Produced in the hypothalamus; Stored in and released by the posterior pituitary gland • Also known as vasopressin
Antidiuretic Hormone (ADH) • Increases water re-absorption from the nephron by increasing the permeability of distal and collecting tubules • Causes urine to become more concentrated • Helps regulate osmotic pressure and therefore water content of body fluids
Osmoregulation • Preventing Dehydration by controlling the volume of water in blood • Control of osmotic pressure • This is a good example of the endocrine and nervous systems working together: more than one response by the body required to maintain homeostasis
Blood osmolarity increases (H2O in blood too low) ↓ ↓ Detection by osmoreceptors Hypothalamus in hypothalamus increases ADH production ↓ ↓ Body feels thirsty ADH released from pituitary ↓ ↓ Drink water ADH sent to kidneys ↓ ↓ Blood osmolarity Kidneys increase decreases reabsorption of water into blood ↓ Blood osmolarity decreases
Formation of Nitrogenous Wastes Protein is digested in stomach & small intestine ↓ ↓ Most amino acids Excess amino acids used to build protein broken down in liver ↓ ↓ Carbon-rich Nitrogenous byproduct used in respiration waste = ammonia ↓ ↓ converted to converted to urea in amphibians uric acid in reptiles, and mammals birds and insects
When things go wrong: • Kidney Stones • Calcium mineral deposits • Must pass through the ureter & urethra to pass • May cause excrutiating pain! • Gout • Tender, hot & swollen joints • Caused by improper formation of nitrogenous wastes (too much uric acid!) • Crystallization of uric acid in joints