Information about Autoregulation
Autoregulation is a specific form of homeostasis used to describe the tendency of the body to keep blood flow constant when blood pressure varies.[1].
While most systems of the body show some degree of autoregulation, it is most clearly observed in the kidney, the heart, and the brain.[2] Perfusion of these organs (especially the latter two) is essential for life, and through autoregulation the body can divert blood (and thus, oxygen) where it is most needed.
One key component of autoregulation is the absence of central control. The "auto" in autoregulation refers of the abiliity of the organ to maintain a stable flow without the involvement of the autonomic nervous system.
There are two main techniques by which renal autoregulation is maintained:[4]
The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a hormone system that helps regulate long-term blood pressure and extracellular volume in the body.
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While most systems of the body show some degree of autoregulation, it is most clearly observed in the kidney, the heart, and the brain.[2] Perfusion of these organs (especially the latter two) is essential for life, and through autoregulation the body can divert blood (and thus, oxygen) where it is most needed.
One key component of autoregulation is the absence of central control. The "auto" in autoregulation refers of the abiliity of the organ to maintain a stable flow without the involvement of the autonomic nervous system.
Renal autoregulation
In the kidneys, autoregulation is primarily concerned with maintaining renal blood flow and glomerular filtration rate.[3]There are two main techniques by which renal autoregulation is maintained:[4]
- Myogenic mechanism: as blood flow increases, the afferent arterioles are stretched, they contract, and subsequently reduce blood flow
- Tubuloglomerular feedback: the macula densa "senses" the blood pressure and causes vasoconstriction
Cardiovascular autoregulation
In the heart, the behavior of autoregulation is similar to that in the kidney, but there is no macula densa involved in the circuit. In the case of heart tissue that is in a state of high metabolic activity, autoregulation occurs due to increased metabolic bi-products such as lactic acid, carbon dioxide, and decreased oxygen and causes coronary vessel dilation. The autoregulation of coronary vessels is mediated by the equilibrium of ATP, ADP, AMP, and Adenosine in the myocardial cell. When there is a high amount of oxygen, the equilibrium is shifted towards ATP. When there is a lack of oxygen, it is shifted toward Adenosine. Adenosine causes vasodilation and therefore increases the supply of oxygen.Cerebral autoregulation
More so than most other organs, the brain is very sensitive to overperfusion, and cerebral autoregulation plays an important role in maintaining an appropriate blood pressure to that region. More detail is available at Cerebral perfusion pressure.See also
References
Homeostasis is the property of either an open system or a closed system, especially a living organism, to regulate the state of its internal environment so as to maintain a stable, constant condition.
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Blood flow is the flow of blood in the cardiovascular system. The discovery that blood flows is attributed to William Harvey.
Mathematically, blood flow is described by Darcy's law (which can be viewed as the fluid equivalent of Ohm's law) and approximately
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Mathematically, blood flow is described by Darcy's law (which can be viewed as the fluid equivalent of Ohm's law) and approximately
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The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases of the kidney is called nephrology[1].
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heart is a muscular organ responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in the annelids, mollusks, and arthropods.
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In animals, the brain or encephalon (Greek for "in the skull"), is the control center of the central nervous system, responsible for behavior. The brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing,
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2, −1
(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1
Atomic radius 60 pm
Atomic radius (calc.
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(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1
Atomic radius 60 pm
Atomic radius (calc.
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autonomic nervous system (ANS) (or visceral nervous system) is the part of the peripheral nervous system that acts as a control system, maintaining homeostasis in the body. These maintenance activities are primarily performed without conscious control or sensation.
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The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases of the kidney is called nephrology[1].
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In the physiology of the kidney, renal blood flow (RBF) is the volume of blood delivered to the kidneys per unit time. In humans, the kidneys together receive roughly 20% of cardiac output, amounting to 1 L/min in a 70-kg adult male.
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Glomerular filtration rate (GFR) is the volume of fluid filtered from the renal (kidney) glomerular capillaries into the Bowman's capsule per unit time.[1] Clinically, this is often measured to determine renal function. Compare to filtration fraction.
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The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood pressure within the blood vessel constant.
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The afferent arterioles are a group of blood vessels that supply the nephrons in many excretory systems.
The afferent arterioles branch from the renal artery which supplies blood to the kidneys.
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The afferent arterioles branch from the renal artery which supplies blood to the kidneys.
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In the physiology of the kidney, tubuloglomerular feedback (TGF) is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). Changes in GFR are detected by the renal tubule, which sends feedback signals to the glomerulus, initiating a cascade
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In the kidney, the macula densa is an area of closely packed specialized cells lining the region of the distal convoluted tubule (DCT) lying next to the glomerular vascular pole.
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Vasoconstriction is a narrowing of the lumen of blood vessels.
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Factors
Factors that trigger vasoconstriction are both of exogenous origin, i.e. medication, and as a response from the body itself.Body mechanisms
Vasoconstriction is a procedure of the body to e.g...... Click the link for more information.
heart is a muscular organ responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in the annelids, mollusks, and arthropods.
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Lactic acid (IUPAC systematic name: 2-hydroxypropanoic acid), also known as milk acid, is a chemical compound that plays a role in several biochemical processes.
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Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state.
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The coronary circulation is the circulation of blood in the blood vessels that supply blood to and from the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, or myocardium, is so thick that it requires coronary blood vessels to
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Cerebral perfusion pressure, or CPP, is the net pressure of blood flow to the brain. It must be maintained within narrow limits because too little pressure could cause brain tissue to become ischemic (having inadequate blood flow), and too much could raise intracranial
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For an autonomous region of Nicaragua, see .
The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a hormone system that helps regulate long-term blood pressure and extracellular volume in the body.
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eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely, two medical doctors. It was sold to WebMD in January 2006.
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