Content
Theurine It is a liquid made up of water and substances separated by the body, and that has functions linked to the elimination of unnecessary substances for the body, or associated with electrolyte control, blood pressure and acid-base balance. Urine is secreted by the kidneys, stored in the bladder, and eliminated during urination.
Normal characteristics: color and smell
Among the most important characteristics of urine is its colour, associated with the amount of water present in it: while the body that consumed a lot of water will have more transparent urine, in more dehydrated bodies it is common for the kidneys to retain water in the body, causing the urine to have a color stronger yellow.
Eventually the urine may have an atypical color, which may be due to benign issues (such as the consumption of strongly colored foods) or due to systemic diseases. When it is normal the urine has no odor, but on certain occasions it can have an unusual smell: like the color, it can be due to benign or minor issues, or to more or less serious diseases.
What is urine made of?
The body usually eliminates about one and a half liters of urine a day. This number, however, is best explained when looking at the composition of the urine:
95% of urine is made up of water, while 2% is made up of mineral salts (as chlorides, phosphates, sulfates, ammonia salts) and 3% organic substances (urea, uric acid, hippuric acid, creatinine). Urine is one of the two main sources of water loss from the body, along with sweat.
How is urine formed?
The formation of urine is a process that consists of three stages:
- Filtration: The blood that is transported by the afferent arteriole reaches the glomerulus, and the plasma solutes pass through the capillaries at a very high speed. Inside the glomerulus, metabolic waste is filtered, and the small nutrients that will be discarded: the passage of a quantity of water gives rise to the formation of a liquid there, which is called glomerular filtrate.
- Tubular reabsorption: The filtered fluid advances through the renal tubules, and there some of the substances are reabsorbed and incorporated into the blood again. Some of the substances that are reabsorbed are water, sodium, glucose, phosphate, potassium, amino acids and calcium.
- Tubular discharge: From the blood plasma to the uriniferous space, a large part of the blood substances is transported, while the waste substances are produced from the tubular capillaries to the lumen of the tubule, in the distal area.
Once formed, the liquid reaches the collecting tube where the only thing it can incorporate is a little more water, so it is not considered one more phase of the formation. However, it is that place where the liquid acquires the name of urine, and is transported to the urinary bladder, where it will be stored until the urination reflex occurs.
Urine analysis
Due to the characteristics of urine is that the analyzes that can be made of its composition are very useful- With a special strip of paper, a test can be done quickly that will show if there are any abnormal products in the urine, the most common of which are sugar, protein or blood.
Diseases such as cystitis, heart disease, or different urinary or kidney infections They can be detected through this type of analysis, which also has the functionality of detecting the consumption of certain drugs that are eliminated through the urine.
