A circulatory system (sometimes cardiovascular system) is an organ system that moves substances to and from cells; it can also help stabilize body temperature and pH (part of homeostasis). There are three types of circulatory systems (from simplest to most complex): no circulatory system, open circulatory system, and closed circulatory system. In biology, an organ (Latin: organum, instrument, tool) is a group of tissues, which perform a specific function or group of functions. ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ... The correct title of this article is pH. The initial letter is capitalized due to technical restrictions. ... Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms. ...

No circulatory system

An example of an animal with no circulatory system is the flatworm (class Turbellaria). Their body cavity has no lining or fluid. They have a mouth leading into a digestive system. The digestive system is very branched, and because the worm is so flat, digested materials can be diffused to all the cells of the flat worm. Oxygen can diffuse from water into the cells of the flatworm. Thus every cell is able to obtain nutrients, water and oxygen without the need of a transport system. Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. ... Orders Acoela Catenulida Haplopharyngida Lecithoepitheliata Macrostomida Nemertodermata Polycladida Prolecithophora Rhabdocoela Seriata Turbellaria are a group of generally small (<1 - 60cm) and free-swimming members of the flatworm phylum Platyhelminthes. ... By the broadest definition, a body cavity is any fluid filled space in a multicellular organism. ... Schematic drawing of the effects of diffusion through a semipermeable membrane. ...

Open circulatory system

An open circulatory system is an arrangement of internal transport present in some invertebrates like mollusks and arthropods in which circulatory fluid in a cavity called the hemocoel (also spelled haemocoel) bathes the organs directly and there is no distinction between blood and interstitial fluid; this combined fluid is called hemolymph (also spelled haemolymph). Muscular movements by the animal during locomotion can facilitate hemolymph movement, but diverting flow from one area to another is limited. When the heart relaxes, blood is drawn back toward the heart through open-ended pores. Invertebrate is a term coined by Jean-Baptiste Lamarck to describe any animal without a spinal column. ... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda The molluscs or mollusks are the large and diverse phylum Mollusca, which includes a variety of familiar creatures well-known for their decorative shells or as seafood. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ... 1. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... Interstitial fluid is one of the two components of extracellular fluid, the other being plasma. ... The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ in vertebrates that pumps blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods. ...

Hemolymph fills all of the interior (hemocoel) of the body and surrounds all cells. Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ...

Hemolymph is composed of water, inorganic salts (mostly Na⁺, Cl^-, K⁺, Mg²⁺, and Ca²⁺), and organic compounds (mostly carbohydrates, proteins, and lipids). The primary oxygen transporter molecule is hemocyanin. Water (from the Old English word wæter; c. ... Inorganic chemistry is the branch of chemistry concerned with the properties and reactions of inorganic compounds. ... A magnified crystal of salt In chemistry, salt is a term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds that by definition contain carbon. ... Carbohydrates are chemical compounds that contain oxygen, hydrogen, and carbon atoms. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Figure 1: Structure of a Lipid. ... Single Oxygenated Hemocyanin protein from Octopus Hemocyanins (also spelled haemocyanins) are respiratory proteins containing two copper atoms that reversibly bind a single oxygen molecule (O2). ...

There are free-floating cells, the hemocytes, within the hemolymph. They play a role in the arthropod immune system. The immune system is the system of specialized cells and organs that protect an organism from outside biological influences. ...

Closed circulatory system

The main organs of the circulatory system is the heart, the blood, and the blood vessels. The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ in vertebrates that pumps blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...

The circulatory systems of all vertebrates, as well as of annelids (for example, earthworms) and cephalopods (squid and octopus) are closed, meaning that the blood never leaves the system of blood vessels consisting of arteries, capillaries and veins. Subgroups †Conodonta Hyperoartia   Petromyzontidae (lampreys) †Pteraspidomorphi †Thelodonti †Anaspida †Cephalaspidomorphi   †Galeaspida   †Pituriaspida   †Osteostraci Gnathostomata (jawed vertebrates)   †Placodermi   Chondrichthyes (cartilaginous fish)   †Acanthodii   Osteichthyes (bony fish)     Actinopterygii (ray-finned fish)     Sarcopterygii (lobe-finned fish)       Actinistia (coelacanths)       Dipnoi (lungfish)       Tetrapoda (four-limbed vertebrates)         Amphibia (amphibians)         Amniota (amniotic embryo)           Sauropsida (reptiles)             Aves (birds)           Synapsida (mammal... Classes and subclasses Class Polychaeta(paraphyletic?) Class Clitellata    Oligochaeta- Earthwormsand others    Acanthobdellida    Branchiobdellida    Hirudinea- Leeches Class Myzostomida Class Archiannelida(polyphyletic) Class Echiura The annelids, collectively called Annelida (from Latin annellus little ring), are a large phylum of animals, comprising the segmented worms, with about 15 000 modern species including the... Families Suborder Haplotaxina   Haplotaxidae Suborder Moniligastrina   Moniligastridae Suborder Lumbricina   Alluroididae   Eudrilidae   Glossoscolecidae   Lumbricidae   Sparganophilidae   Acanthodrilidae   Octochaetidae   Exxidae   Megascolecidae   Microchaetidae   Eudrilidae Suborder Tubificina   Dorydrilidae   Enchytraeidae   Naididae   Opistocystidae   Phreodrilidae   Tubificidae Earthworm is the common name for the larger members of the Oligochaeta (which is either a class or subclass depending on the... Orders Sepiida Sepiolida Spirulida Teuthida Octopoda Vampyromorphida Nautilida The Cephalopods (head-foot) are the mollusk class Cephalopoda characterized by bilateral body symmetry, a prominent head, and a modification of the mollusk foot, a muscular hydrostat, into the form of arms or tentacles. ... Suborders Myopsina Oegopsina Squids are the large, diverse group of marine cephalopods popular as food in cuisines as widely separated as Korean and Italian. ... Families 14 in two suborders, see text. ... Section of an artery An arterial road is a class of highway. ... The word capillary is used to describe any very narrow tube or channel through which a fluid can pass. ... In geology, a vein is a finite volume within a rock, having a distinct shape, filled with mono or poly mineralic crystal aggregates, which were precipitated from an (aqueous) fluid or melt. ...

The systems of fish, amphibians, reptiles, birds and mammals show various stages of evolution. Atlantic herring, Clupea harengus: the most abundant species of fish in the world. ... Orders Subclass Labyrinthodontia- extinct Subclass Lepospondyli- extinct Subclass Lissamphibia   Anura   Caudata   Gymnophiona Amphibians (class Amphibia) are a taxon of animals that include all tetrapods (four-legged vertebrates) that do not have amniotic eggs. ... Orders See text. ... Orders Many - see section below. ... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... A speculative phylogenetic tree of all living things, based on rRNA gene data, showing the separation of the three domains, bacteria, archaea, and eukaryotes. ...

In fish, the system has only one circuit, with the blood being pumped through the capillaries of the gills and on to the capillaries of the body tissues. This is known as single circulation. The heart of fish is therefore only a single pump (consisting of two chambers). gills of a Smooth Newt Gills inside of a tuna head In aquatic organisms, gills are a respiratory organ for the extraction of oxygen from water and for the excretion of carbon dioxide. ...

In amphibians and reptiles, a double circulatory system is used, but the heart is not always completely separated into two pumps. Amphibians have a three-chambered heart. In the first circuit, the blood is pumped to the lungs, where it acquires oxygen. ...

Birds and mammals show complete separation of the heart into two pumps, for a total of four heart chambers; it is thought that the four-chambered heart of birds evolved independently of that of mammals.

Mammalian circulation

Deoxygenated blood (containing little or no oxygen) collects in two major veins: the superior vena cava and the inferior vena cava. The superior and inferior vena cava empty into the right atrium. The right atrium is the larger of the two atriums because it needs to be able to hold the larger amount of blood coming from the body (as opposed to the amount coming from the lungs). The blood is then pumped through the tricuspid atrioventicular valve into the right ventricle. From the right ventricle, blood is pumped through the pulmonary semi-lunar valve into the pulmonary trunk. The deoxygenated blood leaves the heart by the pulmonary arteries and travels through the lungs (where it is oxygenated) and into the pulmonary vein. The oxygenated blood then enters the left atrium. The blood then travels through the bicuspid valve, or mitral valve, into the left ventricle. The left ventricle is thicker and more muscular than the right ventricle because it pumps blood throughout the body, systemic circulation. From the left ventricle, blood is pumped through the semi-lunar valve into the aorta. Once the blood goes through systemic circulation, deoxygenated blood will again collect inside the vena cava and the process will continue. The brachiocephalic veins, superior vena cava, inferior vena cava, azygos vein and their tributaries. ... This article may be too technical for most readers to understand. ... This page is about the muscular organ, the Heart. ... In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... The pulmonary arteries carry blood from the heart to the lungs. ... The pulmonary veins carry blood from the lungs to the left atrium of the heart. ... This page is about the muscular organ, the Heart. ... In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... The largest artery in the human body, the aorta originates from the left ventricle of the heart and brings oxygenated blood to all parts of the body in the systemic circulation. ...

Measurement techniques

• Electrocardiogram
• Sphygmomanometer
• Pulse meter

Lead II An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... Mechanical sphygmomanometer with aneroid manometer and stethoscope Digital sphygmomanometer A sphygmomanometer or blood pressure meter is an inflatable cuff used to measure blood pressure. ... Photo of a heart rate monitor (made by Polar) showing chest strap and watch This article refers to a device used by laypersons. ...

Health and disease

Main article: Cardiovascular disease

Cardiovascular disease refers to the class of diseases that involve the heart and/or blood vessels (arteries and veins). ...

History of discovery

The valves of the heart were discovered by a physician of the Hippocratean school around the 4th century BC. However their function was not properly understood then. Because blood pools in the veins after death, arteries look empty. Ancient anatomists assumed they were filled with air and that they were for transport of air. (5th century BC - 4th century BC - 3rd century BC - other centuries) (2nd millennium BC - 1st millennium BC - 1st millennium AD) // Events Invasion of the Celts into Ireland Battle of the Allia and subsequent Gaulish sack of Rome 383 BCE Second Buddhist Councel at Vesali. ...

Herophilus distinguished veins from arteries but thought that the pulse was a property of arteries themselves. Erasistratus observed that arteries that were cut during life bleed. He ascribed the fact to the phenomenon that air escaping from an artery is replaced with blood that entered by very small vessels between veins and arteries. Thus he apparently postulated capillaries but with reversed flow of blood. Herophilos, sometimes Latinized Herophilus (335-280 BC), was a Greek physician. ...

The 2nd century AD greek physician, Galen knew that blood vessels carry blood and identified venous (dark red) and arterial (brighter and thinner) blood, each with distinct and separate functions. Growth and energy were derived from venous blood created in the liver from chyle, while arterial blood gave vitality by containing pneuma (air) and originated in the heart. Blood flowed from both creating organs to all parts of the body where it was consumed and there was no return of blood to the heart or liver. The heart did not pump blood around, the heart's motion sucked blood in during diastole and the blood moved by the pulsation of the arteries themselves. // Events Roman Empire governed by the Five Good Emperors (96–180) – Nerva, Trajan, Hadrian, Antoninus Pius, Marcus Aurelius. ... Claudius Galenus of Pergamum (131-201 AD), better known in English as Galen, was an ancient Greek physician. ...

Galen believed that the arterial blood was created by venous blood passing from the left ventricle to the right by passing through 'pores' in the interventricular septum, air passed from the lungs via the pulmonary artery to the left side of the heart. As the arterial blood was created 'sooty' vapors were created and passed to the lungs also via the pulmonary artery to be exhaled. A pore, in general, is some form of opening, usually very small. ...

Ibn Nafis(a muslim scholar) in 1242 was the first person to accurately describe the process of blood circulation in the human body. Contemporary drawings of this process have survived. In 1552, Michael Servetus (executed for heresy in 1553) described the same, and Realdo Colombo proved the concept. All these results were not widely accepted however. Ibn Nafis (1210-1288) was the first person to accurately describe the process of blood circulation in the human body (in 1242). ... // Events April 5 - During a battle on the ice of Chudskoye Lake, Russian forces rebuff an invasion attempt by the Teutonic Knights. ... Events April - War between Henry II of France and Emperor Charles V. Henry invades Lorraine and captures Toul, Metz, and Verdun. ... The neutrality of this article is disputed. ... Matteo Realdo Colombo or Renaldus Columbus (c. ...

Finally William Harvey, a pupil of Hieronymus Fabricius (who had earlier described the valves of the veins without recognizing their function), performed a sequence of experiments and announced in 1628 the discovery of the human circulatory system as his own and published an influential book about it. This work with its essentially correct exposition slowly convinced the medical world. Harvey was not able to identify the capillary system connecting arteries and veins; these were later described by Marcello Malpighi. William Harvey (1578–1657) was a medical doctor who is credited with first correctly describing, in exact detail, the properties of blood being pumped around the body by the heart. ... Hieronymus Fabricius Hieronymus Fabricius is the Latin name by which the Italian anatomist Girolamo Fabrici (1537-1619) is better known. ... Events March 1 - writs were issued in February 1628 by Charles I of England that every county in England (not just seaport towns) pay ship tax by this date. ... Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus, (An Anatomical Exercise on the Motion of the Heart and Blood in Animals) is the best-known work of the physician William Harvey. ... Marcello Malpighi (March 10, 1628 - November 29, 1694) was an Italian doctor, who gave his name to several physiological features. ...

See also

• Cardiology
• Lymphatic system
• Blood vessels

Cardiology is the branch of medicine dealing with disorders of the heart and blood vessels. ... Lymph originates as blood plasma lost from the circulatory system, which leaks out into the surrounding tissues. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...

External links

• Cardiovascular Topics
• Studies on Hemodynamics and Coronary Circulation
• The Circulatory System, a comprehensive overview
• The InVision Guide to a Healthy Heart An interactive website

References

• Iskandar, Albert Z. "Comprehensive Book on the Art of Medicine by Ibn al-Nafis". Retrieved May 2, 2005.