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The excretory system is the system of an organism's body that performs the function of excretion, the bodily process of discharging wastes.

• Kidney System
  • Kidneys
  • Nephron
  • Urine
• Lung
  • Carbon dioxide
• Skin
  • Sweat
• Liver
• Malphigian tubule system (Arthropod excretory system)
  • Menses

The Excretory system is responsible for the elimination of wastes produced by homeostasis. There are several parts of the body that are involved in this process, such as sweat glands, the liver, the lungs, and the kidney system. Since we are focusing on the formation of urine within the kidneys, we will simply overview the kidney's role in excretion.

Every human has two kidneys. Each kidney is made up of three sections: the renal cortex, the renal medulla, and the renal pelvis. The blood arrives at the kidney via the renal artery, which splits into many afferent arterioles. These arterioles go to the Bowman's Capsules of nephrons, where the wastes are taken out of the blood by pressure filtration. Peritubular capillaries also surround the nephron so substances can be taken in and out of the blood.

The renal cortex is the outer layer of the kidney and the medulla is the inner layer of the kidney. The renal pelvis takes urine away from the kidney via the ureter. Both of the ureters lead the urine into the body's only urinary bladder, which expands and sends nerve impulses when full. From there, urine is expelled through the urethra and out of the body.

The urinary system is made up of the kidneys, ureters, bladder, and urethra. The nephron, an evolutionary modification of the nephridium, is the kidney's functional unit. Waste is filtered from the blood and collected as urine in each kidney. Urine leaves the kidneys by ureters, and collects in the bladder. The bladder can distend to store urine that eventually leaves through the urethra.

The word excretion means the removal of waste substances from the body. Several organs are involved with the excretory system, including the kidneys, sweat glands, lungs, and rectum. The primary organs of excretions, however, are the kidneys. Excretion is vital to the health of the body because the wastes are poisonous. If the wastes build up and are not eliminated, they can cause serious problems. As you know , carbon dioxide and water vapor are removed by the lungs. Other wastes , namely urea, uric acid, various salts, and assorted nitrogenous wastes , are removed by the kidneys and sweat glands.

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