Urine Formation Vocab

Filtration

As blood moves through glomerular capillaries, water and small solutes are forced out of the blood into the glomerular capsule

Tubular reabsorption

Water, glucose, amino acids, and necessary ions are reabsorbed back into the blood capillaries; occurs along entire tubule portion of nephron

Tubular secretion

Toxins, waste products, hydrogen ions, and potassium ions are actively secreted and removed from peritubular blood capillaries into the tubular fluid; occurs along length of renal tubules

Glomerular filtration rate (GFR)

Volume of filtrate that enters the glomerular capsules per minute; average is 125 mL/min

Glomerular hydrostatic pressure (GHP)

Pressure that blood exerts on the glomerular capillaries; typically around 50 mmHg

Capsular hydrostatic pressure (CsHP)

Pressure filtrate in the glomerular capsule exerts on the walls of the capsule; tends to push water and solutes out of the filtrate and into the glomerular capillaries; typically about 15 mmHg

Blood colloid osmotic pressure (BCOP)

The presence of blood cells, platelets, albumin, and other large proteins in the capillary tends to draw water out of the filtrate and back into the plasma; typically about 25 mmHg

Net filtration pressure (NFP)

Sum of all osmotic and hydrostatic influences; typically about 10 mmHg

Intrinsic controls

Mechanisms inherent within the kidneys to regulate GFR; renal autoregulation

Extrinsic controls

Neural and hormonal regulation of the GFR originating outside the kidneys; includes changing of systemic blood volume and blood pressure