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.

Heart 1
Regulation of blood pressure 2
- Hemodynamics 2.1
Regional circulation 3
References 4
External links 5

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)
- ((Cardiac Output)) is mathematically ` to ((Systole))

- Inotropic, chronotropic, and dromotropic states

- Cardiac input (= heart rate * suction volume Can be calculated by inverting terms in Fick principle)
- Suction volume (= end-systolic volume + end-diastolic volume)
- Injection fraction (=suction volume / end-systolic volume)
- Cardiac input is mathematically ` to (Diastole))

Electrical conduction system of the heart

Regulation of blood pressure

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
Total peripheral resistance (primarily due to vasoconstriction of arteries)
Inotropic state

In turn, this can have a significant impact upon several other variables:

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

^ Overview at Medical College of Georgia
^ Physiology at MCG 3/3ch11/s3c11_13
^ Physiology at MCG 3/3ch11/s3c11_2
^ Physiology at MCG 3/3ch11/s3c11_10

External links

Cardiovascular physiology at the US National Library of Medicine Medical Subject Headings (MeSH)
Cardiovascular Physiology Concepts - Comprehensive explanation of basic cardiovascular concepts, based on a textbook of the same name.
The Gross Physiology of the Cardiovascular System - Mechanical overview of cardiovascular function. Free eBook and video resources.
Clinical Sciences - Cardiovascular An iPhone app covering detailed cardiovascular physiology and anatomy

Physiology of the cardiovascular system

Heart

Volumes	Stroke volume = End-diastolic volume – End-systolic volume Cardiac output = Heart rate × Stroke volume Afterload Preload Frank–Starling law of the heart Cardiac function curve Venous return curve Aortic valve area calculation Ejection fraction Cardiac index

Dimensions	Fractional shortening = (End-diastolic dimension – End-systolic dimension) / End-diastolic dimension

Interaction diagrams	Cardiac cycle Wiggers diagram Pressure volume diagram

Tropism	Chronotropic (Heart rate) Dromotropic (Conduction velocity) Inotropic (Contractility) Bathmotropic (Excitability) Lusitropic (Relaxation)

Conduction system/ Cardiac electrophysiology	Cardiac action potential Atrial action potential Ventricular action potential Effective refractory period Pacemaker potential EKG P wave PR interval QRS complex QT interval ST segment T wave U wave Hexaxial reference system

Chamber pressure	Central venous pressure/right atrial pressure → Right ventricular pressure → Pulmonary artery pressure → Pulmonary wedge pressure/left atrial pressure → Left ventricular pressure → Aortic pressure

Other	Ventricular remodeling

Vascular system/
Hemodynamics

Blood flow	Compliance Vascular resistance Total peripheral resistance Pulse Perfusion

Blood pressure	Pulse pressure Systolic Diastolic Mean arterial pressure Jugular venous pressure Portal venous pressure

Regulation of BP	Baroreflex Kinin–kallikrein system Renin–angiotensin system Vasoconstrictors/Vasodilators Autoregulation Myogenic mechanism Tubuloglomerular feedback Cerebral autoregulation Paraganglia Aortic body Carotid body Glomus cell

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Cardiovascular physiology