What Factors Influence Net Filtration Pressure?

Where does ultrafiltration occur?

In renal physiology, ultrafiltration occurs at the barrier between the blood and the filtrate in the glomerular capsule (Bowman’s capsule) in the kidneys..

Can Net filtration pressure be negative?

The net driving force (NDF) for fluid movement is the net pressure gradient determined by the sum of the individual hydrostatic and oncotic pressures, and is expressed in the units of mmHg. When the NDF is positive, there is net fluid filtration, and when it is negative, there is net fluid reabsorption.

How do kidneys respond to reduced blood flow?

When the kidneys receive low blood flow, they act as if the low flow is due to dehydration. So they respond by releasing hormones that stimulate the body to retain sodium and water. Blood vessels fill with additional fluid, and blood pressure goes up.

What happens to GFR when blood pressure increases?

Increased blood volume and increased blood pressure will increase GFR. Constriction in the afferent arterioles going into the glomerulus and dilation of the efferent arterioles coming out of the glomerulus will decrease GFR. Hydrostatic pressure in the Bowman’s capsule will work to decrease GFR.

What does a positive net filtration pressure mean?

(A) A positive net filtration pressure refers to a condition that favors the movement of fluid out of the capillary lumen and into the surrounding interstitial fluid (i.e., fluid filtration out of the capillary).

Will drinking water increase my GFR?

Water ingestion can acutely affect GFR, although not necessarily in the direction one might expect. Using 12 young, healthy individuals as their own controls, Anastasio et al. found increased water intake actually decreases GFR.

Does high blood pressure increase GFR?

The relationship between blood pressure (BP) and the kidney is complex, and each may adversely affect the other. It has been hypothesized that slightly reduced glomerular filtration rate (GFR) might be associated with increased BP, but this has not been investigated.

What is normal net filtration pressure?

NET FILTRATION PRESSURE (NFP) is the total pressure that promotes filtration. To calculate NFP, we subtract the forces that oppose filtration from the GBHP. A normal NFP (using the figures mentioned) would be: NFP=55-(15+30)=55-45=10mm Hg.

How edema is formed?

Edema results from increased movement of fluid from the intravascular to the interstitial space or decreased movement of water from the interstitium into the capillaries or lymphatic vessels. The mechanism involves one or more of the following: Increased capillary hydrostatic pressure. Decreased plasma oncotic pressure.

What pressures affect the net filtration pressure at the glomerulus?

Glomerular filtration occurs when glomerular hydrostatic pressure exceeds the luminal hydrostatic pressure of Bowman’s capsule. There is also an opposing force, the osmotic pressure, which is typically higher in the glomerular capillary. Figure 1. The NFP is the sum of osmotic and hydrostatic pressures.

What are the factors that affect GFR?

We analyzed the factors that are thought to affect changes in GFR, such as age, sex, body mass index (BMI), preoperative GFR, preoperative creatinine level, operated side, presence of diabetes mellitus (DM), presence of hypertension (HTN), and duration of follow-up.

What is effective filtration pressure?

The effective filtration pressure (EFP) is the total pressure that promotes filtration, is determine as follows: Glomerular blood hydrostatic pressure minus the colloidal osmotic pressure of blood and capsular hydrostatic pressure.

What is glomerular hydrostatic pressure?

glomerular blood hydrostatic pressure (GBHP) – The hydrostatic force which is the mechanical pressure exerted on the fluid of plasma by the pumping of the heart during systole and by the elastic recoil and smooth muscle contraction in the walls of the arteries between heart beats during diastole, and especially by the …

What is capillary filtration?

The primary force driving fluid transport between the capillaries and tissues is hydrostatic pressure, which can be defined as the pressure of any fluid enclosed in a space. … Thus, fluid generally moves out of the capillary and into the interstitial fluid. This process is called filtration.

What two pressures oppose filtration and what are their values?

48 Cards in this SetWhat force drives filtration at the glomerulus?Blood pressureBlood pressure in the glomerulus is about ___mmHg60mmHgWhat two pressures oppose filtration and what are their values?Capsular hydrstatic pressure (15mmHg) Osmotic pressure of blood (28mmHg)What is the normal net filtration pressure?17mmHg44 more rows

What happens when capsular hydrostatic pressure increases above normal?

What would happen if the capsular hydrostatic pressure were increased above normal? Net filtration would increase above normal. Net filtration would decrease. Filtration would increase in proportion to the increase in capsular pressure.

What increases Net filtration pressure?

Increases in the glomerular capillary hydrostatic pressure cause increases in net filtration pressure and GFR. However, increases in Bowman space hydrostatic pressure causes decreases in filtration pressure and GFR. This may result from ureteral constriction.

What factors influence renal filtration rate?

Both glomerular capillary hydrostatic pressure and renal blood flow are important determinants of the glomerular filtration rate (GFR).