Kidney Function: NFP and GFR

Questions and Answers

What does the term Net Filtration Pressure (NFP) refer to?

The osmotic pressure in Bowman's Capsule

The pressure in the renal tubules

The pressure that inhibits filtration

The pressure that promotes filtration (correct)

What is the formula for calculating NFP?

NFP = HPgc - (OPgc + HPcs)

What does glomerular filtration rate (GFR) represent?

The amount of filtrates formed in all renal corpuscles of both kidneys combined

What is the average GFR rate?

125 ml/min Signup and view all the answers

To maintain homeostasis of body fluids, the kidneys need to

maintain a relatively constant GFR Signup and view all the answers

If GFR is too high, what happens to needed substances?

They pass through the renal tubule too quickly to be reabsorbed Signup and view all the answers

If GFR is too low, what happens to filtrate components?

They are reabsorbed and certain waste products are not adequately secreted Signup and view all the answers

GFR is directly related to what other factor?

NFP Signup and view all the answers

What does HPgc stand for?

Hydrostatic pressure of blood in glomerulus Signup and view all the answers

What is the value of HPgc?

55 mm Hg Signup and view all the answers

What does HPcs stand for?

Hydrostatic pressure of fluid in Bowman's Capsule Signup and view all the answers

What is the value of HPcs?

15 mm Hg Signup and view all the answers

What does OPgc stand for?

Osmotic pressure of plasma proteins in blood Signup and view all the answers

What is the value of OPgc?

30 mm Hg Signup and view all the answers

Study Notes

Net Filtration Pressure (NFP)

Net Filtration Pressure (NFP) is the total pressure that promotes the filtration process in the kidneys.
NFP formula: NFP = HPgc - (OPgc + HPcs), where each variable represents different pressures involved in filtration.

Glomerular Filtration Rate (GFR)

Glomerular filtration rate (GFR) measures the amount of filtrate produced by all renal corpuscles in both kidneys.
On average, GFR is 125 ml/min, indicating the kidney's capacity for filtration.

Importance of GFR

The kidneys must maintain a relatively constant GFR to ensure homeostasis of body fluids.
A GFR that is too high results in essential substances passing through the renal tubule too quickly, reducing reabsorption.
Conversely, if GFR is too low, many filtrate components are reabsorbed, impairing waste elimination.

Relationship Between NFP and GFR

GFR is directly related to NFP; changes in NFP will affect the filtration rate in the kidneys.

Hydrostatic and Osmotic Pressures

HPgc (Hydrostatic Pressure of Glomerulus) is the pressure exerted by blood in the glomerulus, facilitating fluid outflow; value is 55 mm Hg.
HPcs (Hydrostatic Pressure in Bowman's Capsule) opposes glomerular filtration by resisting fluid movement; value is 15 mm Hg.
OPgc (Osmotic Pressure of Glomerular Capillary) is due to plasma proteins in blood, pulling fluid back towards the glomerulus; value is 30 mm Hg.

Description

This quiz covers essential concepts related to Net Filtration Pressure (NFP) and Glomerular Filtration Rate (GFR) in the kidneys. Understand the formulas, importance, and the relationship between NFP and GFR in maintaining homeostasis. Test your knowledge on how these factors influence kidney function and fluid balance in the body.