What are the different parts of the nephron?
The correct answer and explanation is:
The nephron is the functional unit of the kidney, responsible for filtering blood, removing waste, and maintaining fluid and electrolyte balance. It consists of several distinct parts, each playing a specific role in the filtration process:
- Bowman’s Capsule: This is a cup-shaped structure that surrounds the glomerulus, a network of capillaries. The Bowman’s capsule is where the filtration of blood begins. The blood pressure forces water, ions, and small molecules from the blood into the Bowman’s capsule, forming the filtrate, which is the precursor to urine.
- Glomerulus: This is a cluster of tiny blood vessels located within the Bowman’s capsule. It plays a key role in filtration. The blood flowing through the glomerulus is filtered under pressure, and substances such as water, glucose, amino acids, and urea pass into the Bowman’s capsule.
- Proximal Convoluted Tubule (PCT): After the Bowman’s capsule, the filtrate enters the proximal convoluted tubule. The PCT is responsible for reabsorbing most of the water, sodium ions, glucose, and amino acids back into the bloodstream. The cells lining the PCT are rich in mitochondria, which provide energy for active transport processes.
- Loop of Henle: The loop of Henle is a U-shaped structure that extends into the medulla of the kidney. It has a descending limb that allows water to be reabsorbed and an ascending limb that actively transports sodium, potassium, and chloride ions out of the filtrate, which helps in the concentration of urine.
- Distal Convoluted Tubule (DCT): The filtrate then passes into the distal convoluted tubule. Here, more reabsorption of sodium and calcium ions occurs. Additionally, this segment plays a role in secreting substances such as potassium and hydrogen ions into the filtrate, helping maintain the body’s electrolyte balance.
- Collecting Duct: Finally, the filtrate reaches the collecting duct, where water reabsorption is regulated by hormones like antidiuretic hormone (ADH). The collecting duct collects urine from several nephrons and channels it toward the renal pelvis for excretion.
Each part of the nephron is specialized to carry out specific functions, contributing to the overall process of filtering blood, maintaining homeostasis, and producing urine.