Why a fish, a rabbit and a pigeon get rid of nitrogen in three different ways. Then the parts of the human excretory system, the layers of the kidney and the nephron, the unit that makes the urine, with its blood supply.
3 lessons, about 1 h 30 min3 simulations11 problems3 practice questionsPython in every lesson
Created by StemPy LabCells make wastes all the time, and the most important of them contain nitrogen. Animals remove nitrogen as ammonia, urea or uric acid, and the choice depends on how much water the animal can spend. This lesson explains the three ways and the animals that follow each.
The human excretory system has two kidneys, two ureters, a urinary bladder and a urethra. Each kidney has an outer cortex and an inner medulla, with about a million nephrons. This lesson takes the kidney apart, layer by layer, and follows the urine out.
The nephron is the working unit of the kidney. It has a glomerulus in a Bowman's capsule and a long tubule, with the proximal tubule, the loop of Henle, the distal tubule and the collecting duct. Two sets of capillaries surround it. This lesson follows the fluid along the nephron and shows how its parts are placed in the cortex and the medulla.
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