Table of Contents
- 1 What is the relationship between renal blood flow and glomerular filtration rate?
- 2 What is the glomerular filtration rate GFR and how is it regulated?
- 3 What forces govern the glomerular filtration?
- 4 How is glomerular circulation regulated?
- 5 What are the three mechanisms that regulate renal flow?
- 6 How is renal function regulated?
- 7 How does systemic blood pressure affect the renal filtration rate?
- 8 What are autoregulatory mechanisms of GFR and RBF?
What is the relationship between renal blood flow and glomerular filtration rate?
Because renal blood flow and GFR normally change in parallel, any increase in renal blood flow causes an increase in GFR. The increased renal O2 consumption (GFR) is offset by an increase in renal oxygen delivery (renal blood flow). This results in a constant arteriovenous O2 difference across the kidney.
What is the glomerular filtration rate GFR and how is it regulated?
GFR is determined by pressure differences between the glomerulus and Bowman’s capsule of the renal tubule. 3. GFR is regulated independent of mean arterial pressure (MAP) between 80-‐180 mmHg by changing the resistance of the renal arterioles.
What is autoregulation of renal blood flow and GFR?
Autoregulation. Renal blood flow (RBF) and glomerular filtration rate (GFR) remain stable over a wide range of perfusion pressures (240). As perfusion pressure falls there is vasodilatation of the afferent arteriole and vasoconstriction of the efferent arteriole which maintains RBF and GFR.
What regulates renal blood flow?
Regulation of renal blood flow is mainly accomplished by increasing or decreasing arteriolar resistance. There are two key hormones that act to increase arteriolar resistance and, in turn, reduce renal blood flow: adrenaline and angiotensin.
What forces govern the glomerular filtration?
The forces that govern filtration in the glomerular capillaries are the same as any capillary bed. Capillary hydrostatic pressure (Pc) and Bowman’s space oncotic pressure (πi) favor filtration into the tubule, and Bowman’s space hydrostatic pressure (Pi) and capillary-oncotic pressure (πc) oppose filtration.
How is glomerular circulation regulated?
How is glomerulus pressure regulated?
A reduction in the mean arterial pressure tends to decrease the afferent arteriole pressure; however, this is accompanied by an increase in the efferent arteriole pressure, which acts to maintain the glomerular capillary hydrostatic pressure.
What interacting controls stabilize the GFR?
Pressure tends to push water and solute molecules out of the plasma into the filtrate. Autoregulation maintains GFR despite changes in local blood pressure and blood flow by changing the diameters of afferent arterioles, efferent arterioles and glomerular capillaries.
What are the three mechanisms that regulate renal flow?
Autoregulation of renal blood flow (RBF) is caused by the myogenic response (MR), tubuloglomerular feedback (TGF), and a third regulatory mechanism that is independent of TGF but slower than MR.
How is renal function regulated?
The kidneys regulate circulatory volume by controlling sodium and water balance, thus maintaining extracellular fluid volume (ECFV) homeostasis. Simply put, an increase in sodium and water consumption leads to an increase in ECFV, which in turn increases blood volume.
What is GFR (glomerular filtration rate)?
Glomerular filtration rate (GFR) represents the flow of plasma from the glomerulus into Bowman’s space over a specified period and is the chief measure of kidney function.
How is blood flow regulated in the kidney?
Summary of Regulation of renal blood flow. Blood flow can be regulated within the kidney by changing arteriolar resistance through several hormonal, autonomic, and autoregulatory mechanisms. Depending on the balance of resistance in the afferent and efferent arterioles, glomerular blood flow and glomerular filtration rates can be fine tuned.
How does systemic blood pressure affect the renal filtration rate?
So a high systemic blood pressure and a low resistance in the renal arterioles, leads to a high renal blood flow and, in turn, glomerular filtration rate, and vice versa. Regulation of renal blood flow is mainly accomplished by increasing or decreasing arteriolar resistance.
What are autoregulatory mechanisms of GFR and RBF?
Autoregulatory mechanisms of Glomerular Filtration Rate (GFR) and Renal Blood Flow (RBF) refer to those processes that appear to operate intrinsically within the kidney itself and can be reproduced even in isolated organs.