Question

1. If a drug was taken that blocked sodium reabsorption, what changes (if any) would be seen in the reabsorption of water and chloride, and in the secretion of hydrogen ions? Why?

2. Provide a list of all structures that glomerular filtrate will pass through from the time it leaves the bloodstream in the glomerular capsule to the time it leaves the body. Ensure that your structure list is in order.

3. How does the structure of a nephron encourage concentration of urine? What is the name of this process and how does it work? (3pts)

Answer 1

1. Most of the reabsorption process in the nephron takes place in the proximal convoluted tubule. The sodium is reabsorbed via sodium symporters and sodium Na+/H+ antiporters. Sodium symporters help sodium reabsorption to the tubule cell where the Na+/H+ antiporters move sodium into the tubule cell and H+ ions out of the cytosol to the tubular lumen. The water also reabsorbed along with sodium ( obligatory reabsorption). So during tubular reabsorption, the sodium and water are reabsorbed and H+ ions are secreted.

When a drug that blocked sodium reabsorption, sodium and water reabsorption will not take place in the tubules and hydrogen ion secretion will be decreased. More sodium and water will be excreted through urine H+ ions stay inside the cytosol.

2. Neurons are the functional units of kidneys. When the filtered fluid reaches the renal corpuscle, it enters into the Glomerular (bowman's) capsule for filtration. Glomerular capsules are the double-walled epithelial cup that surrounds the glomerular capillaries. From the glomerular capsule, the filtrate passes through the renal tubule which has three parts. The Proximal convoluted tubule, the loop of Henle, and distal convoluted tubule. After several secretion and reabsorption process, the remaining fluid passes to the collecting duct and from there to the papillary ducts. From the papillary duct, it enters into renal papilla, minor calyx, major calyx, renal pelvis, ureter, urinary bladder, and urethra.

Glomerular capsules → Proximal convoluted tubule → Descending limb of the loop of Henle → Ascending limb of the loop of Henle → Distal convoluted tubule → Collecting duct → Papillary ducts → Renal papilla →   Minor calyx → Major calyx → Renal pelvis → Ureter → Urinary bladder → Urethra → Out of the body,