Urinary system: Definition, and Functions of the Urinary System

Urinary system: Definition

The Urinary System is a collection of organs in the body that filter waste and other chemicals from the bloodstream. Urine is the means through which the chemicals are filtered out of the body. Urine is a liquid excreted through the urethra that is produced by the kidneys, collected in the bladder, and discharged by the urethra. Urine is used to remove surplus minerals and vitamins from the body, as well as blood corpuscles.

The kidneys, ureters, bladder, and urethra are all urinary organs. The urinary system collaborates with the body’s other systems to maintain homeostasis. the kidneys are the most critical organs in maintaining homeostasis Because they regulate the blood’s acid-base balance and water-salt balance,


1. The process of excretion is one of the most important activities of the urinary system.

2. Excretion is the process of removing waste products of metabolism and other non-essential components from an organism.

 3. The urinary system regulates the amount of water discharged in the urine to maintain a proper fluid volume.

4. Excretion is carried out by several body organs, but the kidneys are the most significant excretory organ.

5. The kidney’s major job is to keep the internal environment steady (homeostasis) so that cell and tissue metabolism can run smoothly. They achieve this by filtering the blood for urea, mineral salts, poisons, and other waste items. They also provide a source of water, salt, and electrolytes. For life to be sustained, at least one kidney must operate properly. The kidneys serve six vital functions:

A.Plasma ionic composition regulation. The amount of sodium, potassium, calcium, magnesium, chloride, bicarbonate, and phosphates excreted by the kidneys regulates their levels.

B.Plasma osmolarity is controlled. Because they have direct control over how many ions and how much water a person excretes, the kidneys regulate osmolarity.

C.Plasma volume regulation. Your kidneys play such an essential role in your health that they even affect your blood pressure. By managing how much water a person excretes, the kidneys regulate plasma volume. The volume of plasma has a direct impact on total blood volume, which in turn has a direct impact on blood pressure. Osmosis, or the passage of water into the blood, is caused by salt (NaCl).

D.Plasma hydrogen ion concentration regulation (pH). The kidneys and the lungs work together to keep the pH in check. The kidneys play an important role because they regulate how much bicarbonate is expelled or retained. The kidneys primarily contribute to blood pH regulation by excreting hydrogen ions and reabsorbing bicarbonate ions as needed.

E.The plasma is cleansed of metabolic waste products and foreign contaminants. Nitrogenous waste is one of the most significant things the kidneys excrete. Ammonia is produced while the liver breaks down amino acids. The liver swiftly mixes ammonia with carbon dioxide to produce urea, which is the principal nitrogenous end product of human metabolism. Because urea is less harmful than ammonia, the liver converts it to urea. Creatinine is produced through the breakdown of creatine phosphate in the body (a high-energy phosphate in muscles). Uric acid is insoluble, so if there is too much of it in the blood, it can pile up and form crystals, which can lead to kidney stones.

F.Hormone Secretion The endocrine system relies on the kidneys to help it release hormones. Renin causes the adrenal cortex to secrete aldosterone, which is then released. Aldosterone encourages the kidneys to reabsorb sodium ions (Na+). When the blood’s oxygen-carrying capacity is depleted, the kidneys release erythropoietin. Erythropoietin is a hormone that increases the formation of red blood cells. The kidneys assist in the activation of Vitamin D from the skin. Vitamin D aids calcium (Ca+) absorption from the gastrointestinal tract.

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