Label the parts or regions of the nephron in the simplified diagram below.
A. E C B. C. F D. B E. D-> F. The microscopic nephrons of the kidney filter and cleanse the blood. The end-product of this filtering and cleansing is urine. Approximately how many nephrons are in one kidney? 1. 2. Where does the blood enter the nephron in the diagram above? Indicate on the diagram. 3. Where does urine leave the nephron? Indicate on the diagram. 4. Where, in the kidney, is urine collected from all the nephrons before going to the bladder?
The Correct Answer and Explanation is :
The nephron is the fundamental structural and functional unit of the kidney, responsible for filtering blood and forming urine. Each human kidney contains approximately 1 to 1.5 million nephrons. citeturn0search7
Labeling the Nephron Diagram:
In a simplified nephron diagram, the following components are typically labeled:
- A. Glomerulus: A network of capillaries where blood filtration begins.
- B. Bowman’s Capsule: A cup-shaped structure that encases the glomerulus and collects the filtrate.
- C. Proximal Convoluted Tubule (PCT): The first segment of the renal tubule where reabsorption of water, ions, and nutrients occurs.
- D. Loop of Henle: A U-shaped tube that concentrates the urine and conserves water.
- E. Distal Convoluted Tubule (DCT): The segment where further regulation of sodium, potassium, and pH occurs.
- F. Collecting Duct: The channel that receives urine from multiple nephrons and transports it to the renal pelvis.
Blood Entry and Urine Exit Points:
- Blood Entry: Blood enters the nephron through the afferent arteriole, which leads into the glomerulus. In the diagram, this would be indicated at the point where the blood vessel enters the glomerulus.
- Urine Exit: Urine leaves the nephron via the collecting duct. In the diagram, this is shown where the collecting duct channels the urine towards the renal pelvis.
Urine Collection in the Kidney:
After urine exits the nephron through the collecting ducts, it is funneled into the renal pelvis, a central cavity within the kidney. From the renal pelvis, urine flows into the ureter and is transported to the bladder for storage before excretion.
Detailed Explanation:
The nephron plays a crucial role in maintaining the body’s fluid and electrolyte balance. The process begins in the glomerulus, where blood pressure forces water and small solutes out of the blood and into Bowman’s capsule, forming the filtrate. This filtrate then enters the proximal convoluted tubule, where a significant portion of water, glucose, amino acids, and ions are reabsorbed back into the bloodstream.
The filtrate next moves into the Loop of Henle, which extends into the kidney’s medulla. The descending limb of the loop is permeable to water, allowing water to be reabsorbed, while the ascending limb is impermeable to water and actively transports sodium and chloride ions out, contributing to the concentration of the medullary interstitium. This mechanism enables the kidney to produce urine that is more concentrated than blood, conserving water in the body.
Following the Loop of Henle, the filtrate enters the distal convoluted tubule, where further reabsorption and secretion fine-tune the composition of the urine, under the influence of hormones such as aldosterone and parathyroid hormone. Finally, the filtrate, now considered urine, drains into the collecting duct. The collecting ducts from multiple nephrons converge, and as they descend through the medulla, additional water reabsorption can occur under the influence of antidiuretic hormone (ADH), concentrating the urine further. The urine then collects in the renal pelvis, passes into the ureter, and is stored in the bladder until excretion.
This intricate system allows the kidneys to effectively filter blood, remove waste products, and regulate essential bodily functions such as blood pressure, electrolyte balance, and fluid homeostasis.