AP BIOLOGY

Detailed explanation-1: -As blood flows into each nephron, it enters a cluster of tiny blood vessels-the glomerulus. The thin walls of the glomerulus allow smaller molecules, wastes, and fluid-mostly water-to pass into the tubule. Larger molecules, such as proteins and blood cells, stay in the blood vessel.

Detailed explanation-2: -The filtrate absorbed in the glomerulus flows through the renal tubule, where nutrients and water are reabsorbed into capillaries. At the same time, waste ions and hydrogen ions pass from the capillaries into the renal tubule.

Detailed explanation-3: -The filtrate flows from the proximal tubule and into the Loop of Henle. The loop of Henle concentrates the filtrate, by removing more water from it, and passes it to the distal tubule. From the distal tubule it travels to the collecting duct-now called urine.

Detailed explanation-4: -The process by which glomerular filtration occurs is called renal ultrafiltration. The force of hydrostatic pressure in the glomerulus (the force of pressure exerted from the pressure of the blood vessel itself) is the driving force that pushes filtrate out of the capillaries and into the slits in the nephron.

Detailed explanation-5: -Most of the Ca++, Na+, glucose, and amino acids must be reabsorbed by the nephron to maintain homeostatic plasma concentrations. Other substances, such as urea, K+, ammonia (NH3), creatinine, and some drugs are secreted into the filtrate as waste products.