The excretory Power


Have you ever tried breathing in and not breathing out?

If accumulating oxygen in your lungs feel uncomfortable, then you should appreciate the possibility of removing unwanted substances from the body. The same compulsion to remove oxygen from the lungs is seen in the entire body, and that is where the kidneys come in.

The body’s excretory system is made up of many organs that enhance life and well-being. Among these are a pair of bean-shaped organs that control the primary excretory functions of the body while balancing chemicals and substances in the body.

These bean-shaped organs are called the kidneys. However, their core excretory and regulatory functions have earned them the title of “The Excretory Powerhouse.” This article explores the functions of the kidneys and creates awareness of the importance of their processes.

What is so important about the kidney?

In every scientific and technical system, processes and information flow simply because there are mechanisms for sending out what comes in. Without this principle, there is sure to be an overload, resulting in a malfunction.

This rule is also true for the body. If the body has no way of removing waste, medical complications occur, some of which may be life-threatening. This excretory function of the kidney is so important that the International Society of Nephrology (ISN) and the International Federation of Kidney Functions (IFKF) set aside a day every year to observe it.

Every year, the second Thursday in March has been set aside to create awareness and educate the public about the importance of the kidney.



What do the Kidneys look like?


In all humans, the kidneys are located behind the abdominal cavity. They are positioned side by side with the right kidney slightly lower than the left kidney. The adrenal glands, responsible for producing hormones including adrenaline, are found directly on top of the kidney. Each kidney is encapsulated in two layers of fat: the perirenal fat and the pararenal fat. Beneath these layers of fat is the renal capsule that protects the kidney.

The functional surface area of the kidney called the parenchyma is divided into two areas: the outer renal cortex and the inner renal medulla. The nephron, the core functional component of the kidney, is found between the cortex and the medulla. The nephron consists of the renal tubule and renal corpuscle. The entire structure of the kidney works to filter waste products and excrete them from the body.




What exactly do the Kidneys do?

The functions of the kidney cause ripple effects throughout the body. Functional kidneys enhance other systems of the body to perform optimally. The kidneys have an inexhaustive list of life-saving functions. Some of them include:

  • Formation of Urine
  • Secretion
  • Excretion
  • Reabsorption
  • Osmo-regulation
  • Acid-base balance etc

However, in this article, we will explore excretion and regulation.




To excrete simply means to remove, eliminate or separate. This suggests that whatever is being excreted is unwanted. The kidneys help the body get rid of unwanted products through the formation of urine. During urine formation, three major processes occur; filtration, reabsorption, and excretion.

Small molecules are filtered at the renal corpuscle, precisely the glomerulus, leaving cells and large protein molecules. These smaller molecules form the ultrafiltrate and continue the process of urine formation. The ultrafiltrate, which contains water, glucose, amino acids, and other substances, is then reabsorbed via various channels and processes in the nephron.

After reabsorption, the ultrafiltrate then passes out of the nephron through the collecting duct to the ureters before it is finally excreted from the body. The nephron bears the herculean task of filtering, reabsorbing, and excreting the blood supplied to it. The ultrafiltrate is called the urine in the ureter and contains water, drug residues, urea, uric acid, and other substances which are no longer required by the body.


The regulatory function is very important because it helps maintain balance in the body. Substances and chemicals in the body can be very dangerous when in excess of dearth. The kidney plays the severe role of eliminating the excesses and ensuring that there is no deficiency. Some of the regulatory processes include:


  1. Sodium and water: The kidneys coordinate the reabsorption of sodium, potassium, and water using three hormones, namely, antidiuretic hormone (ADH), aldosterone, and atrial natriuretic hormone (ANH). These hormones ensure that the body does not lose these very important substances during filtration.
  2. Acid-base balance: The kidney balances acid and base levels by secreting H+ ions into the urine and reabsorbing HCO3 from the ultrafiltrate. This process is very important because it also helps to balance the blood pH. High and low acidity levels in the blood are called acidosis and alkalosis, respectively. These are dangerous conditions that harm the body’s vital organs and even lead to death.
  3. Blood Pressure: The renin-angiotensin system is a holistic hormonal system that affects blood pressure and fluid balance by increasing or reducing the absorption of sodium chloride.
  4. High levels of renin result in high levels of angiotensin II and aldosterone, which in turn relaxes the ECF and blood pressure. In the same vein, low renin levels result in decreased levels of angiotensin II and aldosterone, which in turn contracts the ECF and reduces blood pressure.

Consequently, these influential organs completely control excretion in the body. A sick kidney causes chronic ailments that could lead to death if not properly managed. Fortunately, early discovery of such ailments will go a long way in rescuing a person from chronic renal diseases.

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Though world kidney day is observed once a year, it is advisable to care for your kidney every day.