How does selective reabsorption occur in proximal convoluted tubule?
Selective reabsorption takes place in the proximal convoluted tubule (PCT) of the kidney. It is the process by which certain substances that are required by the body (such as glucose, amino acids, vitamins and water) but have been filtered out of the blood during ultrafiltration, are reabsorbed.
Where does selective reabsorption takes place in the kidney?
proximal convoluted tubule
Selective reabsorbtion occurs in the PCT (proximal convoluted tubule). The PCT is highly permeable meaning it is easy for molecules to diffuse through it.
What does the proximal convoluted tubule do in the kidney?
The proximal convoluted tubule avidly reabsorbs filtered glucose into the peritubular capillaries so that it is all reabsorbed by the end of the proximal tubule. The mechanism for glucose reabsorption was described in Chapter 7.4. The proximal tubule is the only site for glucose reabsorption.
What is selectively reabsorbed in the kidney?
The blood is filtered at a high pressure and the kidney selectively reabsorbs any useful materials such as glucose, salt ions and water.
Which substances are selectively reabsorbed in the proximal tubule?
Most of the solute reabsorbed in the proximal tubule is in the form of sodium bicarbonate and sodium chloride, and about 70% of the sodium reabsorption occurs here. Sodium reabsorption is tightly coupled to passive water reabsorption, meaning when sodium moves, water follows.
How does sodium reabsorption by the proximal tubule drive the reabsorption of other solutes such as glucose?
As sodium diffuses into the tubular cell down its concentration gradient, other solutes such as glucose are “dragged” into the cell with the sodium. Transport maximum is the maximum amount of a solute that can be reabsorbed due to saturation of carrier proteins.
What is proximal convoluted tubule?
Definition of proximal convoluted tubule : the convoluted portion of the vertebrate nephron that lies between Bowman’s capsule and the loop of Henle and functions especially in the resorption of sugar, sodium and chloride ions, and water from the glomerular filtrate.
Why the process in proximal convoluted tubule is called as reabsorption not absorption?
It is called reabsorption (and not absorption) because these substances have already been absorbed once (particularly in the intestines) and the body is reclaiming them from a postglomerular fluid stream that is on its way to becoming urine (that is, they will soon be lost to the urine unless they are reabsorbed from …
What is the function of the proximal tubule?
The proximal tubules are a major component of the kidney and are responsible for the reabsorption of the majority of the glomerular ultrafiltrate, along with the reabsorptive or secretory transport of a vast number of solutes regulating the fluid-electrolyte and acid-base regulation of the body.
What happens in the proximal tubules?
The proximal tubule efficiently regulates the pH of the filtrate by exchanging hydrogen ions in the interstitium for bicarbonate ions in the filtrate; it is also responsible for secreting organic acids, such as creatinine and other bases, into the filtrate.
What substances are selectively reabsorbed?
Answer: Two substances which are selectively reabsorbed from the tubules of a nephron are Amino acids and Glucose.
What is reabsorbed and secreted in the proximal convoluted tubule?