L4 Renal tubular reabsorption and secretion (P1 Hard)

The process where substances from the tubular fluid are moved back into the bloodstream, returning them to the body.

The process of moving substances from the bloodstream into the tubular fluid, potentially for excretion.

Reabsorption occurs between cells, through the spaces between them.

Reabsorption happens directly through cells, requiring crossing through multiple barriers.

Movement driven by concentration difference, where substances move from high to low concentration without energy expenditure.

Movement against concentration gradient, requiring energy expenditure.

A type of active transport where the energy is directly from ATP.

A type of active transport where the energy comes from the concentration gradient of another substance being transported.

The process by which the kidneys filter phosphate from the blood and return it back to the bloodstream.

The process by which the kidneys filter calcium from the blood and return it back to the bloodstream.

The process by which phosphate is transported across the cell membrane of the proximal convoluted tubule (PCT) in the kidneys.

The proximal convoluted tubule (PCT) of the kidneys is where most of the phosphate reabsorption occurs.

The parathyroid hormone (PTH) regulates phosphate reabsorption in the kidneys by inhibiting the reabsorption process.

A process where substances move from the tubular fluid back into the blood.

The movement of sodium ions (Na+) from the tubular fluid into the epithelial cells lining the tubules. This movement is driven by active transport, which uses energy to move sodium against its concentration gradient.

A carrier protein that transports both sodium and glucose across the luminal membrane of the tubular cells. This process is important for reabsorbing glucose from the filtrate.

The return of glucose from the tubular fluid back into the blood. This process occurs mainly in the proximal convoluted tubule (PCT) and is a passive, downhill movement driven by the concentration gradient.

The point at which the blood glucose level is so high that the kidneys can no longer reabsorb all of the glucose filtered from the blood. This causes glucose to appear in the urine.

The active transport of potassium (K+) ions across the apical membrane of tubular cells. This movement is driven by the sodium-potassium pump, which uses energy to move potassium against its concentration gradient.

The process by which phosphate and calcium ions are returned from the tubular fluid back into the blood. This occurs primarily in the proximal convoluted tubule (PCT).

The normal plasma concentration of a substance above which it begins to appear in the urine. For example, if the renal threshold for phosphate is 4mg/dL, that means that if the plasma phosphate concentration is above 4mg/dL, then some phosphate will be excreted in the urine.

Substances like Cl-, H2O, and urea that are reabsorbed passively, relying on the movement of other substances like Na+ for their transport.

The reabsorption of water in the proximal convoluted tubule (PCT) is mostly obligatory, meaning it is driven by the reabsorption of Na+ and occurs regardless of the body's hydration status.

This type of water reabsorption can be adjusted based on the body's hydration needs. It is primarily regulated by the hormone ADH.

Urea reabsorption in the proximal convoluted tubule (PCT) is a passive process that is closely linked to Na+ reabsorption. As Na+ is reabsorbed, urea concentration increases in the tubular fluid, facilitating its passive movement back into the blood.

An increase in blood urea levels, often caused by a decline in kidney function, leading to a buildup of waste products in the blood. It can lead to various health complications.

The primary way that hydrogen ions (H+) are excreted from the body. They are actively secreted into the renal tubules, contributing to acid-base balance.

The active transport mechanism primarily involved in H+ secretion in the proximal convoluted tubule (PCT). It involves an exchange of H+ for Na+.

Hydrogen ions (H+) are actively secreted in the distal convoluted tubule (DCT) and collecting duct (CD) through a primary active transport system. This system involves a pump that utilizes ATP to move H+ against its concentration gradient.

The regulation of hydrogen ion (H+) secretion by the renal tubules, ensuring proper acid-base balance in the body. It's influenced by factors like plasma H+ concentration and PCO2.

K+ transport in the kidneys can involve both reabsorption and secretion, depending on the needs of the body. This process is crucial for maintaining K+ balance.

The primary mechanism responsible for K+ excretion in the urine. It involves the active secretion of K+ from the distal convoluted tubule (DCT) and collecting duct (CD) into the tubular fluid.

The regulation of K+ secretion by the kidneys, ensuring adequate K+ levels in the body. It's influenced by factors such as plasma K+ concentration, aldosterone, and renin-angiotensin system activity.

The process by which substances that are filtered from the blood in the glomerulus are further processed in the renal tubules. It involves both reabsorption and secretion.