Excretory System

In this way, many substances that are not used by the body, especially toxic ones, are excreted from the body.

It is important to emphasize that the excretory system is responsible for much more than just eliminating waste. It is primarily responsible for controlling the chemical composition of the internal environment.

How the Excretory System Works

The elimination of harmful substances or substances that are in excess in our body is called excretion, a process that allows for the internal balance of our organism.

The products of excretion are called “excreta”, which are released from the cells into the fluid that bathes them (interstitial fluid), and from there are passed into the lymph and blood.

In the process of carbohydrate and lipid degradation, carbon dioxide and water are produced. Proteins are also metabolized, and their metabolism results in substances that are harmful to the body, including carbon dioxide and nitrogenous products, such as ammonia, urea and uric acid.

There is also water and mineral salts, with emphasis on sodium chloride (the main component of table salt).

To eliminate these substances, excretion is carried out through urine, breathing and sweat. Understand, below, how the excretion of these residues is done.

Urine Excretion

Excretion through urine begins with a process carried out by the kidneys. They act as a filter that retains impurities in the blood and leaves it in a condition to circulate throughout the body.

The kidneys participate in the control of plasma concentrations of ions, such as sodium, potassium, bicarbonate, calcium and chlorides.

Depending on the concentrations in the blood, these ions can be eliminated in greater or lesser quantities in the urine, through the urinary system. The main substances that form urine are urea, uric acid and ammonia.

Excretion of Carbon Dioxide

Carbon dioxide is excreted through the organs of the respiratory system. The elimination of this element is the end product of the metabolism of glycides (carbohydrates or sugars) and lipids (fats) in the process of cellular respiration.

In addition, water is also eliminated in the form of vapor, through exhalation.

Sweat Excretion

Sweat production is not related to the excretion process but rather to temperature regulation in the body.

However, mineral salts, such as sodium chloride, and water are eliminated through sweat, and due to its enormous importance for the cell, it is largely preserved in the body.

Organs that act in the Excretory System

To eliminate the waste from the chemical reactions that our body produces, different organs perform extremely important functions.

Find out below what these organs are and how they work in the excretory system.

Kidneys

The kidneys are organs of the urinary system, but they act directly in the elimination of waste that results from the action of the body’s metabolism.

Considering the substances eliminated by the kidneys, urea, creatine and blood toxins stand out.

In addition to this function, it also acts to regulate the body’s fluid volume and control blood pressure.

Nephrons

Nephrons are structures present in the kidneys whose main function is to form urine. They filter elements from the blood plasma and then eliminate them in the urine.

Located in the kidneys, they are present in large quantities in the human body, with approximately 1,200,000 nephrons in each kidney.

Ureters

The ureter is a tube that connects the kidney to the bladder, that is, it transports urine from the kidneys to the bladder, with one ureter for each kidney. It is one of the elements of the urinary system that helps in the excretion of unwanted substances.

To perform its function, it performs peristaltic movements that help carry urine to the bladder. To do this, its wall is formed by three different layers, which are formed by a mucous layer, a muscular layer and an adventitious layer.

urinary bladder

The urinary bladder is the organ responsible for storing urine produced by the kidneys and transported by the ureters. In addition to storage, it is also responsible for eliminating urine.

This is a muscular organ with high elastic capacity, as it can store up to 800 ml of urine.

Urethra

The urethra is the canal responsible for carrying urine out of the body. It is connected to the urinary bladder.

In men, the urethra ends in the penis, while in women it ends in the vulva.