Excretory System! Emma, Lizzie, Caitlin, and Natalie

Urinary System There are four key players: 2 Kidneys: filters water, mineral ions, & organic wastes. Gives back 99% of the water and solutes to the blood, the 1% it keeps is the urine 2 Ureters: a tubular channel for urine to pass between the kidney and the urinary bladder 1 Urinary bladder: a muscular sac that stores the urine before sending it to the urethra 1 Urethra: a muscular tube that carries the urine from the bladder to outside of the body

Basic Function It balances the amount of salts and water in the body --Osmoregulation: process that regulates body fluids and salt levels It eliminates the liquid waste products "Bladder Diagram." ENCOGNITIVE.COM. Ed. Elmer Lee. N.p., n.d. Web. 08 Nov Shah, Pravina. "Welcome ToGujarat Kidney Foundation."..::WelCome to Gujarat Kidney Foundation::.. N.p., n.d. Web. 08 Nov

Kidney Movie! 0:00 to 0:37 VY

About the Nephron: There are millions of nephrons in each kidney and they play the most important role in filtering and making adjustments to the water and solutes in the blood It starts as a Bowman's capsule where the wall cups around the glomerular capillaries to form the blood filtering unit: the glomerulus. The Nephron has a proximal tubule, a hairpin-shaped loop of Henle, and distal tubule. It ends as a collecting duct which leads the fluid into the renal pelvis and then into the ureter.

The Nephron The main function of the nephron is to secrete sodium to create a hypertonic exterior compared to the hypotonic tubule. Water will diffuse out of the tubules through Osmosis to balance the concentration of water and sodium secreted outside of the tubule Urine forms in nephrons by three processes: filtration, tubular reabsorption, and tubular secretion

Processes of Urine Formation Filtration: Blood pressure from the heart's contractions drives filtration. Takes place at the glomerulus, pressure "filters" blood by forcing water and solutes (everything EXCEPT protein) out of the glomerular capillaries into the proximal tubule. High filtration rate is possible because glomerular capillaries are times more permeable to water/small solutes. Filtration rate depends on flow volume to the kidneys. When blood pressure decreases kidneys receive less total volume of blood. Tubular Reabsorption: The process of reclaiming water and solutes from the tubular fluid and returning them to the blood. It's along the nephron's tubular regions, moving from nephron wall into peritubular capillaries. Membrane transport proteins move solute across the wall to the peritubular capillaries. Tubular Secretion: A process in which the renial tubule extracts chemicals from capillary blood and secretes them into the tubular fluid. Happens in the tubule wall in the opposite direction of reabsorption. The main solutes are H+ and K+ ions. Prevents foreign substances from accumulating in the blood.

Mardiana, Siti. "Nukilan Rasa from the Beginner." : Mammal's Kidney. N.p., 02 May Web. 08 Nov Transport, Active and Passive

Homeostasis The excretory system regulates the balance of water and ions in the body fluid. It adjusts how much ions and water the body excretes and maintains It establishes an equilibrium through Osmosis (water diffusion) to balance the concentration of water and sodium secreted outside of the tubule

Analogy The excretory system is very similar to a coffee filter. When you make coffee, you add grinds (solute or ions) to water (solvent) to give the beverage its taste. Then when you pour the liquid into a cup to drink, you must use a coffee filter to remove the grinds and leave the mixture of water and coffee for you to enjoy. The coffee filter is similar to the kidneys which adjust the filtrate composition, returning all except 1% (urine) to the blood. The filter returns most of the flavor to the drink but keep the 1% of grinds separate.

References: 1. Elcheguevarra. "Urinary System." YouTube. YouTube, 03 May Web. 08 Nov Elmer, Lee. "Bladder Diagram." ENCOGNITIVE.COM. N.p., n.d. Web. 08 Nov Mardiana, Siti. "Nukilan Rasa from the Beginner." : Mammal's Kidney. N.p., 02 May Web. 08 Nov Shah, Pravina. "Welcome ToGujarat Kidney Foundation. "WelCome to Gujarat Kidney Foundation::.. N.p., n.d. Web. 08 Nov Starr, Cecie. "Digestion and Human Nutrition." Biology The Unity and Diversity of Life. N.p.: n.p., n.d Print.