Information about Cardiovascular Physiology
Cardiovascular physiology is the study of the circulatory system. More specifically, it addresses the physiology of the heart ("cardio") and blood vessels ("vascular").
These subjects are sometimes addressed separately, under the names "cardiac physiology" and "circulatory physiology".[1]
Although the different aspects of cardiovascular physiology are closely interrelated, the subject is still usually divided into several subtopics.
When there is a major and immediate decrease (such as that due to hemorrhage or standing up), the body can increase the following:
Chronotropic effects (from chrono-, meaning time) 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.
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These subjects are sometimes addressed separately, under the names "cardiac physiology" and "circulatory physiology".[1]
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 (= heart rate * stroke volume. Can also be calculated with Fick principle.)
- Stroke volume (= end-diastolic volume - end-systolic volume)
- Ejection fraction (= stroke volume / end-diastolic volume)
- Inotropic, chronotropic, and dromotropic states
- Electrical conduction system of the heart
- Electrocardiogram
- Cardiac pacemaker
- Cardiac action potential
- Frank-Starling law of the heart
- Wiggers diagram
- Pressure volume diagram
Blood vessels
- See Blood vessel#Physiology for more details
- Compliance
- Microcirculation
- Starling equation
- Fick's law of diffusion
- Poiseuille's law
- Skeletal-muscle pump
Regulation of blood pressure
- Baroreceptor
- Baroreflex
- Renin-angiotensin system
- Renin
- Angiotensin
- Juxtaglomerular apparatus
- Aortic body and carotid body
- Autoregulation
Hemodynamics
Under most circumstances, the body attempts to maintain a steady mean arterial pressure.When there is a major and immediate decrease (such as that due to hemorrhage or standing up), the body can increase the following:
- Heart rate
- Total peripheral resistance (primarily due to vasoconstriction of arteries)
- Inotropic state
- Stroke volume
- Cardiac output
- Pressure
- Pulse pressure (systolic pressure - diastolic pressure)
- Mean arterial pressure (usually approximated with diastolic pressure + 1/3 pulse pressure)
- Central venous pressure
Regional circulation
| Name of circulation | % of cardiac output | Autoregulation | Perfusion | Comments |
| pulmonary circulation | 100% (deoxygenated) | Vasoconstriction in response to hypoxia | ||
| cerebral circulation | 15%[2] | high | under-perfused | Fixed volume means intolerance of high pressure. Minimal ability to use anaerobic respiration |
| coronary circulation | 5% | high | under-perfused | Minimal ability to use anaerobic respiration. Blood flow through the left coronary artery is at a maximum during diastole (in contrast to the rest of systemic circulation, which has a maximum blood flow during systole.) |
| splanchnic circulation | 15% | low | Flow increases during digestion. | |
| hepatic circulation | 15% | Part of portal venous system, so oncotic pressure is very low | ||
| renal circulation | 25% | high | over-perfused | Maintains glomerular filtration rate |
| skeletal muscular circulation | 17%[3] | Perfusion increases dramatically during exercise. | ||
| cutaneous circulation | 2%[4] | over-perfused | Crucial in thermoregulation. Significant ability to use anaerobic respiration |
References
1. ^ Overview at Medical College of Georgia
2. ^ Physiology at MCG 3/3ch11/s3c11_13
3. ^ Physiology at MCG 3/3ch11/s3c11_2
4. ^ Physiology at MCG 3/3ch11/s3c11_10
2. ^ Physiology at MCG 3/3ch11/s3c11_13
3. ^ Physiology at MCG 3/3ch11/s3c11_2
4. ^ Physiology at MCG 3/3ch11/s3c11_10
External links
- MeSH Cardiovascular+physiology
- www.cvphsysiology.com - Comprehensive explanation of basic cardiovascular concepts.
Cardiovascular system, physiology: cardiovascular physiology | |
|---|---|
| Volumes | Preload - Afterload - End-systolic volume - End-diastolic volume - Frank-Starling law of the heart |
| Interactions | Cardiac output - Wiggers diagram - Pressure volume diagram |
| Tropism | Chronotropic - Dromotropic - Inotropic |
| Hemodynamics | Baroreflex - Kinin-kallikrein system - Renin-angiotensin system - Vasoconstrictors - Vasodilators - Compliance - Vascular resistance |
| Other | Electrical conduction system of the heart (Cardiac action potential) |
Circulatory System is a psychedelic rock musical ensemble formed by musician/painter Will Cullen Hart, and featuring Hannah Jones, Derek Almstead, Peter Erchick, John Fernandes, and Heather McIntosh.
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Physiology (from Greek: φυσις, physis, “nature, origin”; and λόγος, logos, "knowledge") is the study of the mechanical, physical, and biochemical functions of living organisms.
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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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The blood vessels are part of the cardiovascular system and function to transport blood throughout the body. The most important types, arteries and veins, carry blood away from or towards the heart, respectively.
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Cardiac output (CO) is the volume of blood being pumped by the heart, in particular by a ventricle in a minute.
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Normal Output
Cardiac output is equal to the stroke volume (SV) multiplied by the heart rate (HR)...... Click the link for more information.
Heart rate is a term used to describe the frequency of the cardiac cycle. It is considered one of the four vital signs. Usually it is calculated as the number of contractions (heart beats) of the heart in one minute and expressed as "beats per minute" (bpm).
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Stroke volume is the amount of blood pumped by the left ventricle of the heart in one contraction.
The stroke volume is not all of the blood contained in the left ventricle. The heart does not pump all the blood out of the ventricle.
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The stroke volume is not all of the blood contained in the left ventricle. The heart does not pump all the blood out of the ventricle.
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Fick principle is a technique for measuring cardiac output.
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Variables
The following variables are measured:[1]- VO2 consumption per minute using a spirometer (with the subject re-breathing air) and a CO2 absorber
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Stroke volume is the amount of blood pumped by the left ventricle of the heart in one contraction.
The stroke volume is not all of the blood contained in the left ventricle. The heart does not pump all the blood out of the ventricle.
..... Click the link for more information.
The stroke volume is not all of the blood contained in the left ventricle. The heart does not pump all the blood out of the ventricle.
..... Click the link for more information.
In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in a ventricle at the end of filling (diastole). Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload
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End-systolic volume (ESV) is the volume of blood in the ventricles just after systole. The amount of blood in the ventricle at the end of the cardiac ejection period and immediately preceding the beginning of ventricular relaxation; a measurement of the adequacy of cardiac
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In cardiovascular physiology, ejection fraction (Ef) 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
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An inotrope (IPA: [ˈaɪnətrop]) is an agent which increases or decreases the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions.
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Chronotropic effects (from chrono-, meaning time) 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.
..... Click the link for more information.
A dromotropic agent is one which affects the conduction velocity of the AV node, and subsequently the rate of electrical impulses in the heart.[1][2]
Agents that are dromotropic are often (but not always) inotropic and chronotropic.
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Agents that are dromotropic are often (but not always) inotropic and chronotropic.
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- inactivation of certain ion channels.
Electrochemical Mechanism
- See main article: Cardiac action potential
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electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical activity of the heart over time.
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pacemaker cells, and they directly control the heart rate. Artificial devices also called pacemakers can be used after damage to the body's intrinsic conduction system to produce these impulses synthetically.
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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.
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The cardiac action potential differs significantly in different portions of the heart.
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The Frank-Starling law of the heart (also known as Starling's law or the Frank-Starling mechanism) states that the more the ventricle is filled with blood during diastole (end-diastolic volume), the greater the volume of ejected blood will be during the resulting
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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:
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The X axis is used to plot time, while the Y axis contains all of the following on a single grid:
- Blood pressure
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A pressure volume diagram (or P-V diagram, or volume-pressure loop)[1]) is used to describe a thermal cycle involving the following two variables:
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- Volume (on the X axis)
- Pressure (on the Y axis)
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Compliance is a measure of the tendency of a hollow organ to resist recoil toward its original dimensions upon removal of a distending or compressing force. It is the reciprocal of "elastance".
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The microcirculation is the blood flow through blood vessels smaller than 100 µm (i.e. arterioles, capillaries, and venules). The main functions of the microcirculation are transporting blood cells and substances to/from the tissues, and as body coolant in thermoregulation
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Formulated in 1896 by the British physiologist Ernest Starling, the Starling equation illustrates the role of hydrostatic and oncotic forces (the so-called Starling forces) in the movement of fluid across capillary membranes.
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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.
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First law
Fick's first law is used in steady-state diffusion, i.e...... Click the link for more information.
Poiseuille's law is the physical law concerning the voluminal laminar stationary flow Φ of an incompressible uniform viscous liquid (so called Newtonian fluid) through a cylindrical tube with constant circular cross-section.
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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.
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Baroreceptors (or baroceptors) in the human body 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.
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In cardiovascular physiology, the baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms for maintaining blood pressure. It provides a negative feedback loop in which an elevated blood pressure reflexively causes blood pressure to decrease; similarly,
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