Question

4) Explain the location, structure, and functions of each region of a nephron.

Answer 1

The nephron is the functional unit of the kidney. The glomerulus and convoluted tubules of the nephron are located in the cortex of the kidney, while the collecting ducts are located in the pyramids of the kidney’s medulla.

A nephron consists of three parts:

1, renal corpuscle

2. renal tubule

3. associated capillary network, which originates from the cortical radiate arteries.

The renal corpuscle is located in the renal cortex which is composed of a network of capillaries known as the glomerulus, and also a cup-shaped chamber called the glomerular or Bowman’s capsulethat surrounds the glomerulus.The renal corpuscle acts to filter blood. Fluid from blood in the glomerulus is collected in the Bowman's capsule to form "glomerular filtrate", which is then further processed along the nephron to form urine. It does this via a filtration barrier.

The renal tubule is a long, convoluted structure that emerges from the glomerulus. It can be divided into three parts based on function. The first part is called the proximal convoluted tubule (PCT), due to its proximity to the glomerulus. The second part is called the loop of Henle, or nephritic loop, because it forms a loop (with descending and ascending limbs) that goes through the renal medulla. The third part of the renal tubule is called the distal convoluted tubule (DCT); this part is also restricted to the renal cortex. This last part of the nephron connects with and empties its filtrate into collecting ducts that line the medullary pyramids. The collecting ducts contains contents from multiple nephrons, fusing together as they enter the papillae of the renal medulla.The function of the proximal tubule is essentially reabsorption of filtrate in accordance with the needs of homeostasis (equilibrium), whereas the distal part of the nephron and collecting duct are mainly concerned with the detailed regulation of water, electrolyte, and hydrogen-ion balance. All of these processes occur in the tubules through both chemical and physical means, and all are subject to hormonal regulation.

As urine travels down the collecting duct system, it passes by the medullary interstitium, which has a high sodium concentration as a result of the loop of Henle’s countercurrent multiplier system. Urine leaves the medullary collecting ducts through the renal papillae, emptying into the renal calyces, the renal pelvis, and finally into the bladder via the ureter.