Kidney Physiology: Reabsorption and Filtration M 3.3

The capacity of cell membranes to allow water to pass through them.

Reabsorbs glucose, amino acids, bicarbonate, and excretes waste products.

Consists of thin descending, thin ascending, and thick ascending limbs with different functions.

Highly permeable to water and allows simple diffusion, reabsorbing 20% of filtered water.

Impermeable to water, reabsorbs sodium, chloride, and potassium actively.

Maintains low intracellular sodium concentration and enables solute transport.

Utilizes sodium gradient to move other solutes like chloride and potassium.

A slightly positive charge that drives the reabsorption of positively charged solutes.

A substance used to measure Glomerular Filtration Rate (GFR).

The rate at which the kidneys filter blood, indicative of kidney function.

The process where substances are reabsorbed from renal tubules back into the blood.

The region where significant water reabsorption occurs, concentrating filtrate.

Increased tubular reabsorption in response to higher tubular load.

Forces that govern the rate of reabsorption in capillaries.

Mechanisms that maintain stable GFR despite changes in blood pressure.

Normal absorption of water and solutes from the filtrate is about 124 mL/min.

The difference in charge and concentration across a membrane that influences ion movement.

The maximum rate at which substances can be reabsorbed in the renal tubules.

A hormone that regulates sodium and water reabsorption in the kidneys.

The movement of water across a semipermeable membrane from low to high solute concentration.

Proteins that facilitate the rapid transport of water across cell membranes.

Water permeability is influenced by antidiuretic hormone, allowing water recovery.

Section of the nephron that helps concentrate urine by managing water and solute reabsorption.

A measure of kidney function that indicates how well blood is filtered through the kidneys.

The volume of plasma that is cleared of creatinine per unit time, used to estimate GFR.

The total amount of plasma that passes through the kidneys per unit time.

The ratio of GFR to renal plasma flow, indicating how much plasma is filtered by the kidneys.

Processes in the kidneys where substances are either reabsorbed back into the bloodstream or secreted into urine.

The difference between capillary pressure and opposing pressures (interstitial and colloid).

Process of moving fluids back into capillaries from interstitial fluid.

A measure of the capacity of capillaries to filter fluid.

Pressure exerted by a fluid in the capillary that promotes filtration.

Pressure exerted by proteins in the blood that pulls fluid into the capillaries.

The pressure from the interstitial fluid pushing against the capillaries.

Changes in arterial pressure affect hydrostatic pressures in capillaries.

Osmotic pressure from plasma proteins affecting capillary reabsorption.

Atrial natriuretic peptide (ANP) inhibits sodium and water reabsorption in the kidneys, promoting excretion.

Parathyroid hormone increases calcium reabsorption and decreases phosphate reabsorption in the kidneys.

Activation of sympathetic nerves increases renin release and decreases sodium excretion.

Renal clearance is how much plasma is cleared of a substance by the kidneys over time.

Glomerular filtration rate (GFR) can be calculated using inulin, which is neither reabsorbed nor secreted.

Creatinine is a byproduct of muscle metabolism cleared by glomerular filtration, used to estimate GFR.

The kidneys reabsorb sodium and water, which is inhibited by ANP for fluid balance.

The filtration rate of a substance is equal to the rate at which it is excreted, when not reabsorbed.