Cardiovascular physiology is the study of the
circulatory system- [Headline text]--75.137.171.242 01:21, 21 October 2009 :bThe circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, nitrogen waste products, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pHb to maintain...
. More specifically, it addresses the
physiologyPhysiology is the science of the functioning of living systems. It is a subcategory of biology...
of the
heartThe heart is a muscular organ found in all vertebrates that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
("cardio") and
blood vesselThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s ("vascular").
These subjects are sometimes addressed separately, under the names
cardiac physiology and
circulatory physiology.
Although the different aspects of cardiovascular physiology are closely interrelated, the subject is still usually divided into several subtopics.
- See Heart#Physiology for more details
- Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. This is measured in dm3 min-1...
(= heart rateHeart rate is determined by the number of heartbeats per unit of time, typically expressed as beats per minute , it can vary with as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and...
* stroke volumeIn cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. It is calculated by subtracting the volume of blood in the ventricle at the end of a beat from the volume of blood just prior to the beat...
.
Cardiovascular physiology is the study of the
circulatory system- [Headline text]--75.137.171.242 01:21, 21 October 2009 :bThe circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, nitrogen waste products, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pHb to maintain...
. More specifically, it addresses the
physiologyPhysiology is the science of the functioning of living systems. It is a subcategory of biology...
of the
heartThe heart is a muscular organ found in all vertebrates that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
("cardio") and
blood vesselThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s ("vascular").
These subjects are sometimes addressed separately, under the names
cardiac physiology and
circulatory physiology.
Although the different aspects of cardiovascular physiology are closely interrelated, the subject is still usually divided into several subtopics.
Heart
- See Heart#Physiology for more details
- Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. This is measured in dm3 min-1...
(= heart rateHeart rate is determined by the number of heartbeats per unit of time, typically expressed as beats per minute , it can vary with as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and...
* stroke volumeIn cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. It is calculated by subtracting the volume of blood in the ventricle at the end of a beat from the volume of blood just prior to the beat...
. Can also be calculated with Fick principleDeveloped by Adolf Eugen Fick , the Fick principle was first devised as a technique for measuring cardiac output. However, its underlying principles may be applied in a variety of clinical situations....
.)
- Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. It is calculated by subtracting the volume of blood in the ventricle at the end of a beat from the volume of blood just prior to the beat...
(= end-diastolic volumeIn cardiovascular physiology, end-diastolic volume is the volume of blood in a ventricle at the end of filling . Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to...
- end-systolic volumeEnd-systolic volume is the volume of blood in the left ventricle at the end of contraction, or systole, and the beginning of filling, or diastole.ESV is the lowest volume of blood in the ventricle at any point in the cardiac cycle.-Uses:...
)
- Ejection fraction
In cardiovascular physiology, ejection fraction is the fraction of blood pumped out of a ventricle with each heart beat. The term ejection fraction applies to both the right and left ventricles; one can speak equally of the left ventricular ejection fraction and the right ventricular ejection...
(= stroke volume / end-diastolic volume)
- ((Cardiac Output)) is mathematically ` to ((Systole))
-
- Inotropic, chronotropic
Chronotropic effects are those that change the heart rate.Chronotropic drugs may change the heart rate by affecting the nerves controlling the heart, or by changing the rhythm produced by the sinoatrial node...
, and dromotropicDerives from the Greek word "Dromos," meaning avenue or entranceway to a building. A dromotropic agent is one which affects the conduction velocity of the AV node, and subsequently the rate of electrical impulses in the heart....
states
-
- Cardiac input
Cardiac input is the inverse operation of cardiac output .Cardiac output implies ejection fraction.Ejection fraction is an easily understood and imaged mathematical model of systole....
(= heart rateHeart rate is determined by the number of heartbeats per unit of time, typically expressed as beats per minute , it can vary with as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and...
* suction volume Can be calculated by inverting terms in Fick principleDeveloped by Adolf Eugen Fick , the Fick principle was first devised as a technique for measuring cardiac output. However, its underlying principles may be applied in a variety of clinical situations....
- Suction volume (= end-systolic volume
End-systolic volume is the volume of blood in the left ventricle at the end of contraction, or systole, and the beginning of filling, or diastole.ESV is the lowest volume of blood in the ventricle at any point in the cardiac cycle.-Uses:...
+ end-diastolic volumeIn cardiovascular physiology, end-diastolic volume is the volume of blood in a ventricle at the end of filling . Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to...
)
- Injection fraction
Injection fraction is the inverse operation of the myocardial ejection fraction. "Ejection Fraction" is historically derived from Cardiac Output first proposed by Adolph Fick 1829-1901. Ejection fraction is most readily appreciated as the difference between end systolic volume and end diastolic...
(=suction volume / end-systolic volume)
- Cardiac input
Cardiac input is the inverse operation of cardiac output .Cardiac output implies ejection fraction.Ejection fraction is an easily understood and imaged mathematical model of systole....
is mathematically ` to (Diastole))
- Electrical conduction system of the heart
The normal electrical conduction in the heart allows the impulse that is generated by the sinoatrial node of the heart to be propagated to the myocardium . The myocardium contracts after stimulation...
- Electrocardiogram
Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over time captured and externally recorded by skin electrodes. It is a noninvasive recording produced by an electrocardiographic device...
- Cardiac marker
- Cardiac action potential
The cardiac action potential is a specialized action potential in the heart, with unique properties necessary for function of the electrical conduction system of the heart.The cardiac action potential differs significantly in different portions of the heart...
- Frank-Starling law of the heart
The Frank-Starling law of the heart states that the greater the volume of blood entering the heart during diastole , the greater the volume of blood ejected during systolic contraction .This allows the cardiac output to be synchronized with the venous return, arterial blood...
- Wiggers diagram
A Wiggers diagram is a standard diagram used in cardiac physiology.The X axis is used to plot time, while the Y axis contains all of the following on a single grid:* Blood pressure** Aortic pressure** Ventricular pressure** Atrial pressure...
- Pressure volume diagram
A pressure volume diagram ) is used to describe a thermal cycle involving the following two variables:* Volume * Pressure...
Blood vessels
- See Blood vessel#Physiology for more details
- Compliance
- Microcirculation
The microcirculation is a term used to describe the small vessels in the vasculature which are embedded within organs and are responsible for the distribution of blood within tissues; as opposed to larger vessels in the macrocirculation which transport blood to and from the organs...
- Starling equation
The Starling equation is an equation that illustrates the role of hydrostatic and oncotic forces in the movement of fluid across capillary membranes.Capillary fluid movement may occur as a result of two processes:...
- Fick's law of diffusion
Fick's laws of diffusion describe diffusion and can be used to solve for the diffusion coefficient, D. They were derived by Adolf Fick in the year 1855.- Fick's First Law :...
- Poiseuille's law
- Skeletal-muscle pump
The skeletal-muscle pump is a collection of skeletal muscles that aid the heart in the circulation of blood. It is especially important in increasing venous return to the heart, but may also play a role in arterial blood flow.-Venous return:...
Regulation of blood pressure
- Baroreceptor
Baroreceptors are sensors located in the blood vessels of the human body. They detect the pressure of blood flowing through them, and can send messages to the central nervous system to increase or decrease total peripheral resistance and cardiac output...
- Baroreflex
In cardiovascular physiology, the baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms for maintaining blood pressure...
- Renin-angiotensin system
The renin-angiotensin system or the renin-angiotensin-aldosterone system is a hormone system that regulates blood pressure and water balance....
- Renin
Renin , also known as Angiotensinogenase, is a circumsized enzyme that participates in the body's renin-angiotensin system that mediates extracellular volume , and arterial vasoconstriction...
- Angiotensin
Angiotensin, a protein, causes blood vessels to constrict, and drives blood pressure up. It is part of the renin-angiotensin system, which is a major target for drugs that lower blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex...
- Juxtaglomerular apparatus
The juxtaglomerular apparatus is a microscopic structure in the kidney, which regulates the function of each nephron. The juxtaglomerular apparatus is named for its proximity to the glomerulus: it is found between the vascular pole of the renal corpuscle and the returning distal convoluted tubule...
- Aortic body
In the human heart, the aortic body is one of several small clusters of chemoreceptors, baroreceptors, and supporting cells located along the aortic arch.-Function:...
and carotid bodyThe carotid body is a small cluster of chemoreceptors and supporting cells located near the fork of the carotid artery ....
- Autoregulation
Autoregulation is a process within many biological systems, resulting from some internal adaptive mechanism that works to adjust the systems response to stimuli. While most systems of the body show some degree of autoregulation, it is most clearly observed in the kidney, the heart, and the brain...
Hemodynamics
Under most circumstances, the body attempts to maintain a steady
mean arterial pressureThe mean arterial pressure is a term used in medicine to describe an average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.-Calculation:Mean arterial pressure can be determined from:...
.
When there is a major and immediate decrease (such as that due to hemorrhage or
standing upOrthostatic hypotension is a form of hypotension in which a person's blood pressure suddenly falls when the person stands up...
), the body can increase the following:
- Heart rate
Heart rate is determined by the number of heartbeats per unit of time, typically expressed as beats per minute , it can vary with as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and...
- Total peripheral resistance
Vasculature throughout the entire body can be thought of as two separate circuits - one is the systemic circulation, while the other is the pulmonary circulation. Total peripheral resistance is the sum of the resistance of all peripheral vasculature in the systemic circulation...
(primarily due to vasoconstriction of arteries)
- Inotropic state
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction....
In turn, this can have a significant impact upon several other variables:
- Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. It is calculated by subtracting the volume of blood in the ventricle at the end of a beat from the volume of blood just prior to the beat...
- Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. This is measured in dm3 min-1...
- Pressure
- Pulse pressure
Pulse pressure is the difference between systolic and diastolic blood pressure, or the change in blood pressure seen during a contraction of the heart.-Calculation:Formally it is the systolic pressure minus the diastolic pressure....
(systolic pressureSystole , is a phase of the cardiac cycle where the myocardium is contracting in a coordinated manner in response to an endogenous electrical stimulus, and pressure is being generated within the chambers of the heart driving blood flow....
- diastolic pressureDiastole is the period of time when the heart fills with blood after systole . Ballistics accurately describes Diastole as recoil opposed to coil or Systole. Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are...
)
- Mean arterial pressure
The mean arterial pressure is a term used in medicine to describe an average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.-Calculation:Mean arterial pressure can be determined from:...
(usually approximated with diastolic pressure + 1/3 pulse pressure)
- Central venous pressure
Central venous pressure describes the pressure of blood in the thoracic vena cava, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system....
Regional circulation
| Name of circulation |
% of cardiac output Cardiac output is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. This is measured in dm3 min-1...
|
Autoregulation Autoregulation is a process within many biological systems, resulting from some internal adaptive mechanism that works to adjust the systems response to stimuli. While most systems of the body show some degree of autoregulation, it is most clearly observed in the kidney, the heart, and the brain...
|
Perfusion In physiology, perfusion is the process of nutritive delivery of arterial blood to a capillary bed in the biological tissue. The word is derived from the French verb "perfuser" meaning to "pour over or through."...
|
Comments
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| pulmonary circulationPulmonary circulation is the portion of the cardiovascular system which carries oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart...
|
100% (deoxygenated) |
|
|
Vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
in response to hypoxiaHypoxia is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
>-
| cerebral circulationCerebral circulation refers to the movement of blood through the network of blood vessels supplying the brain. The arteries deliver oxygenated blood, glucose and other nutrients to the brain and the veins carry deoxygenated blood back to the heart, removing carbon dioxide, lactic acid, and other...
|
15% |
high |
under-perfused |
anaerobic respiration In biology, anaerobic respiration is a way for an organism to produce usable energy carriers without the involvement of oxygen; it is respiration without oxygen. Respiration is a redox reaction that processes energy in a form usable by an organism, chiefly the process of producing ATP, the...
>-
| coronary circulationCoronary circulation is the circulation of blood in the blood vessels of the heart muscle. Although blood fills the chambers of the heart, the muscle tissue of the heart is so thick that it requires coronary blood vessels to deliver blood deep into it. The vessels that deliver oxygen-rich blood to...
|
5% |
high |
under-perfused |
anaerobic respiration In biology, anaerobic respiration is a way for an organism to produce usable energy carriers without the involvement of oxygen; it is respiration without oxygen. Respiration is a redox reaction that processes energy in a form usable by an organism, chiefly the process of producing ATP, the...
. Blood flow through the left coronary arteryThe left coronary artery, abbreviated LCA and also known as the left main coronary artery , arises from the aorta above the left cusp of the aortic valve.-Branching:...
is at a maximum during diastoleDiastole is the period of time when the heart fills with blood after systole . Ballistics accurately describes Diastole as recoil opposed to coil or Systole. Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are...
(in contrast to the rest of systemic circulationSystemic circulation is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the heart. The term is contrasted with pulmonary circulation.-Course:...
, which has a maximum blood flow during systoleSystole may refer to:*Systole , a term used to describe entry into the imagination in a text*Systole , a term describing the contraction of the heart*Systolic array, a term used in computer architecture...
.)
>-
| splanchnicSplanchnic, from a Greek word meaning organ, usually used to describe soft tissue organs . Can also refer to:* An adjective describing the intestines* Splanchnic nerves* Splanchnic mesoderm...
circulation |
15% |
low |
|
digestionDigestion is the mechanical and chemical breaking down of food into smaller components, to a form that can be absorbed, for instance, by a blood stream. Digestion is a form of catabolism.that means break down of macro food molecules to smaller one....
.
>-
| hepatic circulation |
15% |
|
|
portal venous system In human anatomy, the hepatic portal system is the system of veins comprised of the hepatic portal vein and its tributaries. It is also called the portal venous system, although it is not the only example of a portal venous system, and splanchnic veins, which is not synonymous with hepatic portal...
, so oncotic pressureOncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins in blood plasma that usually tends to pull water into the circulatory system.Throughout the body, dissolved compounds have an osmotic pressure...
is very low
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| renal circulationThe renal circulation receives around 20% of the cardiac output. It branches from the abdominal aorta and returns blood to the ascending vena cava. It is the blood supply to the kidney, and contains many specialized blood vessels.-Circulation:...
|
25% |
high |
over-perfused |
|
>-
| skeletal muscular circulation
17% |
|
|
|
>-
| cutaneous circulation
2% |
|
over-perfused |
Crucial in thermoregulationThermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
. Significant ability to use anaerobic respirationIn biology, anaerobic respiration is a way for an organism to produce usable energy carriers without the involvement of oxygen; it is respiration without oxygen. Respiration is a redox reaction that processes energy in a form usable by an organism, chiefly the process of producing ATP, the...
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External links