Nephrons and Urinary Health: Function, Conditions, and Care
Nephrons: The Functional Units of the Kidney
Each kidney contains about one million nephrons. Nephrons are microscopic tubular structures, approximately 2-3 cm in length and about 5 mm in diameter, capable of forming urine. In their initial part, they have a widened capsule called Bowman’s capsule, which surrounds a ball of blood capillaries known as the glomerulus. The Bowman’s capsule is continuous with a long tubule that is responsible for carrying urine. The tubules forming the collecting ducts end in the renal pelvis.
The Formation of Urine
Urine formation occurs in the nephrons, allowing blood plasma to eliminate toxic substances. This process cleanses the blood and regulates the volume of water in blood plasma. It involves the following phases:
- Glomerular Filtration: Water and other small molecules pass from the blood capillaries of the glomerulus into the Bowman’s capsule through a wall that prevents the passage of large molecules. Some of these molecules are toxic, but some are useful and must be recovered.
- Reabsorption: Up to 99% of the water and all molecules of interest to the body are recovered and returned to the plasma. The rest of the water and toxic substances form urine.
Urinary Health
Renal Stones
When small amounts of liquids are ingested, some substances in the urine can accumulate and crystallize into stones. During the expulsion of these stones, a nephritic colic can occur, caused by the obstruction in the ureters.
Cystitis
Cystitis is an inflammation of the bladder that causes pain, frequent urination, and a burning sensation during urination. It is usually caused by a bacterial infection.
Acute and Chronic Renal Failure
In renal failure, the kidneys stop working completely, and a progressive destruction of nephrons occurs. The lack of urine output leads to the intoxication of the patient and even death. People suffering from renal failure need to undergo hemodialysis, a process where a machine connected to the patient performs the function of the kidney.
Urinary Tract Infections
If organisms enter the inner regions of the urinary tract, an infection can occur. Symptoms include burning with urination, redness, pain, and fever.
Maintenance of the Urinary System
- Maintain an adequate supply of water, drinking 1.5 to 2 liters per day.
- Follow a healthy diet, avoiding foods such as seafood, which produce a load rich in uric acid.
- Avoid alcohol and other toxic substances.
- Maintain proper hygiene in the external urogenital tract and skin.
Other Excretory Organs
The Sweat Glands
Sweat glands are structures distributed throughout the skin that produce sweat. Sweat is a liquid similar to urine, containing mineral salts (especially sodium chloride), urea, uric acid, lactic acid, and potassium. It also plays a significant role in thermoregulation, as it cools the body when it evaporates. Sweat can be controlled through antiperspirants (which should not be used excessively as they impede cutaneous perspiration) and deodorants.
The Liver
In addition to excreting bilirubin, the liver also participates in the degradation of alcohol. Many drugs, hormones, and toxins pass through the liver filter and are modified for elimination in bile and feces. Certain substances can cause irreparable damage to the liver. Cirrhosis is a liver disease due to excessive and continuous consumption of alcohol.
The Lungs
The lungs remove CO2 that arrives in the blood from every cell in the body. They also remove certain highly volatile substances, such as alcohol.