Summary
Kidneys adjust arteriole resistance to keep glomerular filtration steady despite blood pressure changes.
In depth
Myogenic response: stretch makes afferent arterioles constrict. Tubuloglomerular feedback: macula densa senses NaCl and adjusts afferent resistance. GFR remains stable between mean pressures of about 80 and 180 mmHg.
Autoregulation keeps filtration constant despite variable blood pressure. Failure in hypertension damages kidneys.
Example: ACE inhibitors dilate efferent arterioles and reduce glomerular pressure.
Kidneys keep glomerular filtration rate steady across mean arterial pressures of about 80 to 180 mmHg. The myogenic mechanism is a smooth muscle response in the afferent arteriole to stretch. Tubuloglomerular feedback senses NaCl at the macula densa: if filtration rises, delivery of NaCl increases, adenosine release constricts the afferent arteriole and renin is reduced; the reverse occurs when filtration falls. Angiotensin II constricts the efferent arteriole to maintain GFR in low volume states.
NSAIDs, which block prostaglandins that dilate the afferent arteriole, and ACE inhibitors, which dilate the efferent one, can impair filtration in volume-depleted patients (the triple whammy with diuretics). Autoregulation fails below the range, and kidney injury can result in shock.
Key idea: stable filtration is needed because the kidney's work depends on a constant delivery of filtrate.
Frequently asked questions
What is Renal Autoregulation?
Kidneys adjust arteriole resistance to keep glomerular filtration steady despite blood pressure changes.
Which area of biology covers Renal Autoregulation, and how advanced is it?
Renal Autoregulation is one of the 51 topics in Human Physiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Renin-Angiotensin-Aldosterone System, Blood Pressure, Frank-Starling Law.
Can you give an example of Renal Autoregulation?
NSAIDs can reduce renal blood flow by blocking prostaglandins.
What should I learn before Renal Autoregulation?
Work through the Beginner topics in Human Physiology first, such as Homeostasis, Tissues and Organs, Skeletal System, then return to Renal Autoregulation. Advanced topics assume the Intermediate vocabulary.
What topics are related to Renal Autoregulation?
The closest topics to Renal Autoregulation are Renin-Angiotensin-Aldosterone System, Blood Pressure, Frank-Starling Law, Respiratory Control. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Renal Autoregulation?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Renal Autoregulation. To practise the whole of Human Physiology, use the Human Physiology quiz.
How is Renal Autoregulation different from Renin-Angiotensin-Aldosterone System?
Renal Autoregulation: Kidneys adjust arteriole resistance to keep glomerular filtration steady despite blood pressure changes. Renin-Angiotensin-Aldosterone System: A hormone cascade that raises blood pressure by vasoconstriction and sodium retention. Read both side by side and note what each one explains.
How should I study Renal Autoregulation step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Renin-Angiotensin-Aldosterone System and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.