Circulation

Circulation
Name	Circulation
System	Circulatory system
Components	Heart; Vessels; Blood; Lymph
Function	Transport of gases, nutrients, wastes, hormones

Circulation Circulation refers to the bulk movement of fluid within an organism or technical system enabling transport of gases, nutrients, wastes, and signaling molecules; it underpins physiology in humans, animals, and plants while informing engineering in James Watt-era steam technology, Michael Faraday experiments, and Alexander Graham Bell-era teleology. Major historical studies connecting circulation to modern practice invoke names like William Harvey, Andreas Vesalius, Galen, Marcello Malpighi, and institutions such as Royal Society, Académie des Sciences, and Johns Hopkins Hospital. Clinical and experimental contexts link circulation to interventions by figures and entities such as Andreas Vesalius, Ignaz Semmelweis, Florence Nightingale, National Institutes of Health, and World Health Organization.

Overview

Circulation comprises coordinated activity of a pumping organ and conduits that creates directed flow seen in vertebrate hearts, invertebrate dorsal vessels, plant phloem, and engineered systems like the Hubble Space Telescope cooling loops and Fulton Steam Engine condensers. Historical milestones include debates between Galen and William Harvey, observations by Marcello Malpighi, microscopy advances by Antonie van Leeuwenhoek, and surgical adoptions by John Hunter and Joseph Lister. Physiological research centers such as Harvard Medical School, Cambridge University Press publications, and laboratories at Max Planck Society and Massachusetts General Hospital have broadened understanding across species, with clinical guidelines from American Heart Association and European Society of Cardiology guiding practice.

Physiology of Circulatory Systems

In vertebrates the heart, valves, arteries, veins, and capillaries are orchestrated by cardiac conduction involving nodes named in mammalian anatomy and electrophysiology work by Willem Einthoven, Otto Frank, Woldemar Mobitz, and institutions like Mayo Clinic and Cleveland Clinic. Endothelial biology informed by Rudolf Virchow and molecular signaling studied at Cold Spring Harbor Laboratory and Salk Institute link vascular tone to mediators investigated by Furchgott and Ignarro. Hemodynamics integrates pressure-flow relationships formalized in models by Poiseuille and Laplace and used in research at Imperial College London and Johns Hopkins University. Lymphatic circulation, described historically by Olaus Rudbeck and Gabriele Falloppio, interacts with immunity studied at Institut Pasteur and Rockefeller University.

Types of Circulation

Systemic and pulmonary circuits in mammals contrast with single-circuit systems in teleost fishes, explained in comparative work involving Charles Darwin collections and studies at Smithsonian Institution and Natural History Museum, London. Portal systems such as hepatic portal flow were characterized in anatomical atlases produced by Netter and experimental physiology by Claude Bernard; open circulation in arthropods was detailed by entomologists at Royal Entomological Society and invertebrate zoologists like Jean-Baptiste Lamarck. Plant translocation in xylem and phloem was elucidated by botanists at Kew Gardens and by physiologists such as Julius von Sachs and Ludwig Pfeffer. Artificial and extracorporeal circulations—cardiopulmonary bypass, hemodialysis, and ventricular assist devices—were developed through collaborations including John Gibbon Jr., Michael DeBakey, Kolff, Cleveland Clinic, and companies like Medtronic.

Measurement and Quantification

Quantification employs instruments and methods tied to figures and organizations: sphygmomanometry following work by Samuel Siegfried Karl von Basch and Scipione Riva-Rocci for blood pressure, electrocardiography pioneered by Willem Einthoven for cardiac rhythm, thermodilution and Fick principle methods from physiology labs at Guy's Hospital and Beth Israel Deaconess Medical Center for cardiac output, and imaging modalities developed by teams at GE Healthcare, Siemens Healthineers, and Philips for ultrasound, CT, and MRI flow quantification. Hematology measures such as hematocrit and hemoglobin trace to laboratories at Mayo Clinic and standardization by bodies like International Council for Standardization in Haematology. Mathematical modeling of flow uses frameworks from Claude-Louis Navier and George Gabriel Stokes and computational platforms from Los Alamos National Laboratory and MIT.

Disorders and Dysfunction

Pathologies include ischemic events addressed by specialists at American College of Cardiology and stroke centers at Johns Hopkins Hospital, atherosclerosis research conducted at University of Oxford and Karolinska Institutet, venous thromboembolism studies linked to researchers at Royal Brompton Hospital and University College London, and congenital anomalies cataloged by pediatric cardiology units at Great Ormond Street Hospital and Boston Children's Hospital. Therapeutics derive from trials sponsored by National Institutes of Health, drug discoveries by Pfizer and AstraZeneca, interventional techniques by innovators like Andreas Gruentzig and institutions such as Mayo Clinic, and public health programs run by World Health Organization and Centers for Disease Control and Prevention.

Evolution and Comparative Biology

Evolutionary perspectives draw on fossil evidence curated at Natural History Museum, London and Smithsonian Institution, comparative anatomy from work by Ernst Haeckel and Richard Owen, and developmental genetics research at Howard Hughes Medical Institute and European Molecular Biology Laboratory exploring gene networks conserved from Drosophila melanogaster to mammals. Studies of respiratory and circulatory transitions in vertebrate evolution cite fieldwork by Alfred Russel Wallace and modern synthesis contributions from Theodosius Dobzhansky and Stephen Jay Gould, while paleophysiology links to findings by Royal Society-affiliated researchers and museums worldwide.

Category:Physiology