How Kidneys Work – The Vital Role of the Kidney in Human Beings

We celebrate World Kidney Day on every 2nd Thursday of March each year. This year we celebrated on 14th March 2013. Now it is obvious that why do we focus much more in saving our kidneys. What type of work the kidneys really do for us, why they are so important and why it is essential to take care of the kidneys. This article is all about the workings of our kidney. They are the waste disposal system of our body, which keeps on working 24 hours a day, 7 days a week and 365 days of a year – that is without taking a single leave. When it takes a leave, our life comes to danger. Let’s explore why:

What do Kidneys do?
Have you ever thought that what will happen if the garbage collector does not appear for a week or the output of your toilet is chocked? Just imagine, how your home will look like? Similarly we can consider kidneys as garbage disposal unit of our body, without which our life comes to an end.

Kidneys are the bean shaped organ located just under the ribs and in the middle of our back. There are total two kidneys located on either side of our spinal cord. Their weight is about 0.5% of the total body weight and approx. size is about of our feast. Their main task is to purify the blood by removing the wastes.

Every day, a person’s kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination. They requires large amount of blood to perform following tasks:

  • They clean the blood by removing the wastes such as urea, ammonia, toxic substance etc. and keep the essential elements as it is, thus they act as filter of our body.
  • Regulate the composition of blood; they keep constant concentration of various ions and other important substance such as salts and acids in body by purifying and filtering blood.
  • Maintain body’s calcium level.
  • Make red blood cells and help maintain blood composition and pH levels
  • Keep the proper balance of salts and acids in the body, and produce hormones and enzymes which help to control blood pressure, keep internal water level and maintain strong and healthy bones

Inside of Kidney:
Half cut of kidney includes following:

kidney cancer surgery

Parts:
A. Renal Vein: It transmits the processed blood, which is repaid to the body through Renal Vein.
B. Renal Artery: Kidneys obtain the blood from the renal artery; it is processed inside of kidneys.
C. Ureters: It gathers the urine from the kidney and passes to the bladder.
D. Medulla: a darker, reddish-brown, inner region
E. Renal Pelvis – It is a flat, funnel-shaped cavity that collects the urine into the ureters
F. Cortex: A light colored outer region

Nephrons (the enlarged area in this image): They are located between Cortex and Medulla. They are tiny tubular structures stretched perpendicular to the surface of kidney. There are approx. one million of such nephrons.

Each Nephron Contains:
1 & 2. Loop of Henle – A long, hairpin loop after the proximal tubule, it spreads from the cortex down into the medulla and back.
3. Peritubular capillaries – They are nearby the proximal tubule, loop of Henle, and distal tubule.
4. Proximal convoluted tubule or proximal tubule – The first warped region after the Bowman’s capsule; it’s in the cortex.
5. Bowman’s capsule – This closed end at the start of the nephron is placed in the cortex.
6. Distal convoluted tubule or distal tubule – This second warped portion of the nephron after the loop of Henle is located in the cortex.

Overall, the process of waste removal from the body is as follows:

  • We eat the food and it enters into stomach. It is wrecked in to smaller particles and turned into nutrients.
  • This nutrient consists of solid and liquid.
  • The solid part enters into long intestine, where solid waste products are removed and nutrients are absorbed in the blood stream.
  • Such nutrients are used by the body in terms of energy utilization, to fight from the antibodies, and repairing and maintenance of any body part.
  • The wastes are transferred by blood and it then enters into kidneys.
  • Kidney filters blood from the smallest micro part called as Nephrons.
  • The waste is sent to bladder via ureter and it is stored in the bladder. Which we call as urine.
  • When sufficient urine is collected in bladder, the muscles contracts, which gives urge to urinate and we release urine via urethra.

The filtration process is carried out under pressure inside the Bowman’s capsule. The waste is consists of small molecules, small proteins, urea, glucose etc. The capacity of the filtration process is approx. 180 liters a day. This means if we have 7 to 8 liters of blood in our body, then kidney filters blood about 20-25 times each day.

The filtrate only covers small particles and water, and no Red Blood Cells. If we get blood in urine, then it is owing to hematuria. This is a conceivable sign of Kidney failure. If we get such difficulties then it is counseled to consult urologist directly.

Why do kidneys fail?
Maximum kidney diseases attack the nephrons, initiating them to lose their filtering capacity. Damage to the nephrons can happen rapidly, often as the result of injury or poisoning. But most kidney diseases abolish the nephrons leisurely and silently. Only after years or even decades will the damage become apparent. Most kidney diseases attack both kidneys concurrently.

The two most communal reasons of kidney disease are diabetes and high blood pressure. People with a family history of any kind of kidney problem are also at risk for kidney disease.

We will learn about Chronic Kidney Diseases (CKD) in next article.

To summarize, kidney separates blood and the waste. They flush the wastes and keep you healthy. Love your kidneys.