There are at least one million nephrons in each kidney, and together, they drive the kidneys, collectively serving as the functional unit responsible for filtering blood and regulating the body’s fluid balance. As we explore the structure and functions of nephrons, and parts of nephrons, we actually shed light on their significance in maintaining overall health.
Structure of Nephron
There are two kinds of nephrons, superficial cortical nephrons that comprise 70-80%, and the rest being juxtamedullary nephrons. A look at the parts structure of nephrons, we realize that they consist of two primary components: the renal corpuscle and the renal tubule.
Renal Corpuscle
Among the parts of a nephron, the renal corpuscle is a key one and also the initial site of blood filtration. It spearheads the core function nephron, through glomerulus, a network of tiny blood vessels, and the Bowman’s capsule, which surrounds the glomerulus. The glomerulus acts as a sieve, allowing small molecules such as water, electrolytes, and waste products to pass through while preventing the passage of larger molecules such as proteins and blood cells.
Renal Tubule
The next among the major parts of a nephron is renal tubule, a long, convoluted structure that continues from the Bowman’s capsule. It consists of several segments, each with specific functions. These segments include the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.
Functions of Nephron
The Nephron functions are explained below,
Filtration
Filtration is the first step in urine formation and occurs in the renal corpuscle. As blood passes through the glomerulus, the high-pressure forces water, ions, nutrients, and waste products out of the blood and into the Bowman’s capsule. This fluid, known as the filtrate, contains substances that need to be selectively reabsorbed or excreted.
Reabsorption
Reabsorption takes place primarily in the renal tubule. Essential substances, such as glucose, amino acids, and water, are selectively reabsorbed into the surrounding capillaries to be returned to the bloodstream. This process ensures that vital molecules are retained in the body, maintaining balance.
Secretion
Secretion involves the transfer of additional substances, such as excess ions, drugs, and toxins, from the blood into the renal tubule. This process allows the nephron to regulate the concentration of certain substances in the body, aiding in the elimination of waste and maintenance of homeostasis.
Excretion
Excretion is the final step in urine formation. After the filtrate has undergone reabsorption and secretion processes in the renal tubule, it reaches the collecting duct. Here, additional water and solutes are reabsorbed or excreted based on the body’s needs, resulting in the formation of concentrated urine.
Types of Nephrons
There are two main types of nephrons: cortical nephrons and juxtamedullary nephrons.
Cortical Nephrons
Cortical nephrons are the most abundant type, comprising approximately 85% of all nephrons. They are primarily located in the outer region of the kidney cortex and have a shorter loop of Henle. These nephrons are involved in maintaining overall body fluid balance.
Juxtamedullary Nephrons
Juxtamedullary nephrons are located closer to the medulla of the kidney and have a longer loop of Henle. They play a crucial role in producing concentrated urine and are involved in the body’s water conservation mechanisms.
The nephron, as the functional unit of the kidney, performs vital tasks to maintain fluid balance, regulate blood pressure, and eliminate waste products from the body. It is an intricate system that ensures the proper filtration, reabsorption, and secretion processes required for overall health and well-being.
Understanding the structure and functions of nephron, and their types provides valuable insights into the complex processes involved in urine formation. The nephron’s remarkable capabilities enable the body to maintain a delicate balance and eliminate waste effectively. By comprehending the significance of nephrons, we can appreciate the intricacies of the human body’s filtration system.
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