Glomerular Filtration Rate (GFR) – Urine Formation (Nursing)

00:01 The glomerular filtration rate is the volume of filtrate form permanent by both kidneys.

00:08 This is normally about a 120 to a 125 milliliters per minute.

00:15 The glomerular filtration rate or GFR is directly proportional to the net filtration pressure where the primary pressure is going to be our glomerular hydrostatic pressure.

00:28 Also, the GFR is proportional to the total surface area available for filtration.

00:36 Here, the glomerular mesangial cells are going to control this surface area by contracting.

00:44 Finally GFR is directly proportional to filtrate membrane permeability.

00:50 Which is much more permeable than the other capillaries that we find throughout the body.

00:58 A constant GFR is important as it allows for our kidneys to make a filtrate and maintain our extra cellular homeostasis.

01:08 The goal of local intrinsic controls are renal autoregulation is to maintain this GFR in our kidneys.

01:18 Our GFR also affects our systemic blood pressure.

01:22 An increased GFR causes an increased urine output with lower blood pressures and vice versa.

01:31 Also, we have extrinsic controls which are necessary to maintain our systemic blood pressure.

01:38 Our nervous system and our endocrine system are going to be the main extrinsic controls of the kidney.