1. Regulation of extracellular fluid volume and blood pressure 2. Regulation of osmolarity 3. Maintenance of ion balance 4. Homeostatic regulation of pH 5. Excretion of wastes 6. Production of hormones Urinary System: 1 st step water and solutes move from plasma to nephrons that make up most of the kidneys where fluid composition altered, leave kidney and enter ureter, travel urethra. Kidneys make urine, renal arteries blood to kidneys, renal veins blood away from kidneys. Kidney: 2 layers outer cortex and inner medulla. Functional unit of kidney is the nephron. Blood enter kidney through renal artery-> afferent arterioles-> into ball-like network of capillaries=glomerulus-> blood leave efferent arterioles then into peritubular capillaries surround proximal tubule, some enter into the medulla, called vasa recta. Filter fluid out of blood into nephron, then some of the fluid reabsorbed into peritubular capillaries and then into blood Nephron: Begin with Bowman’s capsule surround the glomerulus, fluid filter into it (glomerus+bowmans cap=renal corpuscle). Bowmans->proximal tubule->loop of henle (descending and ascending limbs)->distal tubule- >collecting duct (dist-tubule+collecting=distal nephron)->renal pelvis Portion of distal passes between afferent and efferent arterioles=juxtaglomerular apparatus. Kidney overview: Filtration: move from blood into lumen of nephron only occur at renal corpuscle