|of these articles treats the organ heart. For further meanings see heart (term clarifying).|
The heart (Latin - anatomically the Cor, Greek - pathologically the Kardia, καρδιά or latinisiert Cardia, in each case with stress on the icontrary to the Greek ones) is a muscular hollow organ, which supplies the body by rhythmic contractions with blood and thus the blood circulation of all organs secures. A life without heart is for higher animals and humans not possible - probably howeverwith an artificial heart. The heart belongs to the first organs put on during the Embryonalentwicklung.
shape and size with humans
the shape of the heart resembles one wellcone big as a fist and rounded off, whose point points to the left in front downward and somewhat. The heart sits with humans usually easily to the left transferred behind the breastbone (see further below under topography), in rare cases to the rightshifted (the so-called Dextrokardie - Rechtsherzigkeit), usually with Situs inversus (mirror-wrong organ arrangement).
The healthy heart weighs about 0.5 % of the body weight and on average between 300 and 350 g, whereby it during durable load rather alsoreacts (low-risk) to the enlargement of heart muscle cells already existing - off approx. the risk of a lack supply of the heart with oxygen, increased now, increases 500 g, the critical heart weight in such a way specified, since the supplying Koronararterien along-grows not equally.
The heart of the mammals consists of two parts.
- The right heart half, which pumps the blood by the cycle of the lung (small cycle).
- The left heart half, which carries the blood by the remaining body (large cycle).
Since the entire container-resisted the body cycle is approximately five times larger than that of the lung cycle, the left Herzkammer (S. must. and) accordingly larger pressure a work perform and exhibits therefore a clearly stronger wall thickness thanthe rights. The filling and impact volume of both Herzkammern are however alike.
the heart lies behind the breastbone in the thorax in a bindegewebigen heart bag (Perikard, Pericardium fibrosum), which encloses the heart completely. The internal layer of the heart bag(Pericardium serosum) strikes at the outlet of the large blood vessels (S. and) into the Epikard over, which rests upon directly the heart. Between Perikard and Epikard then a capillary Spaltraum filled with liquid, friction-poor shifts the hearts lies in the heart bagmade possible.
These complicated conditions become more descriptive, if one understands oneself the heart bag as a ballon locked filled with air and. The own hand closed to the fist represents the heart. One imprints the ballon with the fist so far,that it is completely enclosed by the balloon, then a layer of the ballon of the fist (the “heart”) fits directly. This layer, which corresponds to the Epikard, changes at the transition to the arm to an outside layer. This outside layer corresponds to thatPerikard. Between both is an area filled with air, which is comparable to the Spaltraum filled with liquid of the heart bag.
Under the Epikard a fat layer is, in that the heart wreath/ring containers (S. and) run. The thick muscle layer (myocardium) existsfrom specialized muscle tissue, which occurs only in the heart. The interiors are lined by the Endokard, also the Herzklappen (S. and) forms.
Areas and containers
of rights and left heart half consist in each case of a chamber (ventricle)and a forecourt (atrium). These areas are separated by the heart septum. This becomes into the forecourt septum (septum interatriale) and the Kammerscheidewand (septum interventriculare) partitions.
The blood can in the heart areas only into oneDirection flow, since between the forecourts and chambers and the containers following to the chambers Herzklappen are, which work like valves. In right forecourt the upper and lower Hohlvene ( Vena cava superior et inferior) flows.They supply the oxygen-poor (venous) blood from the large cycle to the heart. Between right forecourt and right chamber the Trikuspidalklappe , those is with the chamber contraction (Systole, S. and) like a valve a current reversalthe blood into the forecourt prevents. It possesses three portions, which are fastened to the chamber musculature like sails over chord threads (therefore it also sail flap). Over a common trunk (Truncus pulmonalis) the two Lungenarterien leave the right chamber. Alsobetween chamber and Lungenarterien is a Herzklappe, the Pulmonalklappe. This kind of the flaps is called because of its form also pocket flap. The Lungenarterien supplies the oxygen-poor blood to the lung cycle.
By usually four Lungenvenen the oxygen-rich flows (arterial) blood from the lung cycle the left forecourt too. From here it arrives over a further sail flap, the Mitralklappe at the left chamber. That leak out happens over the Aorta, which possesses like the Lungenarterie a pocket flap (Aortenklappe).
Note: Arterien transport the blood from the heart to the organs, Venen from the organs to the heart. Arterien of the body cycle lead oxygen-rich (arterial) blood, during Arterien of the lung cycle oxygen-poor (venous) blood lead. Turned around the bloodinto the Venen of the body cycle oxygen-poor (venously), that the Lungenvenen oxygen-rich (arterially).
While a heart cycle fill first the forecourts, while the chambers eject the blood at the same time into the Arterien. If the chamber musculature relaxes, openthe sail flaps by the decrease of pressure into the chamber and the blood flows itself from the forecourts. This is supported by pulling the forecourts (Vorhofsystole together). The chamber systole follows: the chamber musculature pulls together, thatPressure rises, the sail flaps closes and the blood can only by the pocket flaps opened now into the Arterien leak out. A return flow of the blood from the Arterien during the relaxation phase (Diastole) becomes by the conclusion of the pocket flapsprevented. The direction of flow is determined thus alone by the flaps.
Topography with humans
the heart lies within the heart bag (Perikard) in the Mediastinum: Laterally border separately by parietale and viszerale Pleura the left and right lung on the heart. Down mount the heart the Zwerchfell, which with the heart bag grow togetheris. Up the bronchial tube ( trachea) divides into the two head bronchi (Bifurcatio tracheae), whose is crossed left by the aortic arch. Behind the left forecourt the esophagus lies in direct contact. Before the heart is the breastbone(Sternum), within the upper range it lies before the outgoing large containers. Between breastbone and heart the thymus lies.
The heart lies thus practically directly behind the front body wall at height second to fifth rib. The heart basis aboveto the right about two centimeters over right edge of breastbone extend. Down the heart point approaches scarcely to a meant senkrechte line, which runs by the center of the left Schlüsselbeins (link Medioklavikularlinie).
Heart wreath/ring containers
from the initial part of the Aorta rise the heart wreath/ring containers (Koronararterien). They supply the heart muscle with blood. The oxygen-poor blood from the heart muscle is led by the Herzvenen into the sine coronarius, which flows directly in right forecourt.
There is a left and a oneright Koronararterie:
- Link Koronararterie (Arteria coronaria sinistra, l eft C oronary A rtery, LCA) for the heart front
- main trunk
- R amus to i of nter v entricularis A nterior (RIVA, l eft A nterior D escending, LOD)
- R amus C ircumfle x US (RCX)
- main trunk
- rights Koronararterie (Arteria coronaria dextra, r ight C oronary A rtery, RCA), which at the back plate into the Ramus interventricularis posterior changes, before it gives it however still the A. marginalis more dexter off,which right edge of heart supplies.
- Koronarvenen: runs in front in the Sulcus interventricularis with the R. interventricularis anterior the Vena cardiaca/cordis interventricularis anterior, which on height of splitting the A. coronaria sin. into their two Rami into V. cardiaca/cordis magna turns into,which to the sine coronarius becomes for its part. The sine coronarius takes V. from the rear side. cardiaca/cordis media and of the right edge of heart V. cardiaca/cordis parva up.
thereby itself the electrical excitation, for thoseHeart action is responsible, over the heart to spread can, is connected the individual heart muscle cells by small pores in its cell membranes. Over these Gap Junctions flow ions from cell to cell. The excitation takes in the sine knot between upper Hohlvene andits origin to right Herzohr, spreads and reaches only over both forecourts then over the AV-knots in the valve level the chambers. The valve level, in which also the four Herzklappen lie, consists of connective tissue and is up to the AV-knotfor the electrical excitation impermeable.
In the two Herzkammern there is an excitation line system to the faster Fortleitung, which consists of specialized heart muscle cells. These cells form outgoing from the AV-knot his bundle, in right and a left Tawara thigh forthe right and the left chamber divide. The left Tawara thigh divides into a left front and a left rear bundle. The final distance of the excitation line system formed by Purkinje fibers, which run up to the heart point, there to turn around and directly under thatEndokard (S. o.) in the work musculature end. Partially they can pull also as wrong chord threads by clearing the chamber. This system makes possible for the chambers to contract itself despite its size coordinated.
Reach the AV-knot for any reason none, Then a slower chamber excitation goes to forecourt excitations out from it (approx. 50 /min). The AV-knot forms also a frequency-selective filter, for that to fast forecourt excitations (z. B. with forecourt flutter or - flicker) abblockt (see. AV-block).
The heart pumps to peace aboutthe entire blood volume of the body once per minute by the cycle, that are about five litres per minute. During physical load the pumping performance can be increased approximately on the fivefold, whereby the Sauerstoffbedarf increases accordingly. This increase becomes througha duplication of the impact volume and an increase of the heart frequency around the factor 2.5 reaches. With each pumping action promotes each chamber somewhat more than half of their filling volume, approx. 50 - 100 ml blood. The heart frequency (impacts/minute) amounts to in peace 50- 80/min (with newborn children over 120-160) and can rise under load to 200 /min. If a too slow heart impact lies forwards (under 60/min.), of a bradycardia one speaks.
The heart frequency of animals depends essentially on the size of the animal.The heart of the blue whale about strikes even when effort only 18 to 20 times in the minute, that the mouse about 500 times per minute.
during physical load is increased the heart achievement by the effect of sympathetic nerve fibers, onthe cells of the work musculature and also the excitation line system the transmitter Noradrenalin set free. Additionally Noradrenalin as well as adrenalin reaches the heart as hormone by means of the bloodstream. The effect of Noradrenalin and adrenalin is obtained predominantly over Beta-1-Rezeptoren and consists of oneIncrease of the heart strength (positively inotropic), the heart frequency (positively chronotropic) and the transition speed in the AV-knot (positively dromotropic).
The opponent of the Sympathikus is also at the heart of the Parasympathikus, that with the transmitter acetyl choline the heart frequency, the contractible force of the heart and the transition speed of the AV-knot lower (negatively chronotropicly, inotropicly and dromotropically).
At the same time the contractible force adapts to the requirements automatically: If the heart muscle is more stretched by additional blood volume, then thereby the function improvesthe kontraktilen elements in the muscle cells (franc Starling mechanism). This mechanism contributes substantially to the fact that the impact volume does not differ from right and left chamber medium-term: If the impact volume of a heart half increases at short notice for any reason, then this leadsto an enlargement filling volumes of the other heart half with the following heart action. Thus the wall is more stretched and the chamber can likewise eject a larger blood volume with improved contractible force.
The heart produces a urine-driving in its forecourts also stretch-dependentlyHormone, the atriale natriuretische Peptid (ANP), in order to exert influence on the circulating blood volume.
loses sexual differences according to a study of the University of Liverpool with healthy men between that 18. and 70. Lebensjahr a quarter of its pumping performance, if itnot by physical activities one trains. With women such changes are only slight, the causes are not exactly clarified.
The Kardiologie is occupied diseases in the medicine as specialization of the internal medicine with the heart and in such a way specified conservative therapy of the heart illnesses (for operations the heart surgeons are responsible), so far however not with the innate heart false formations. These fall, so far conservatively therapierbar, into the field of activity of the Kinderkardiologie, which itself as subsection of the Pädiatrie in the last 40 yearsdeveloped, and/or. with necessity for operational therapy into the field of the child heart surgery at least established in Germany as specialization. There since approx. 20 years increasingly children with complex innate heart errors the adult age reach, places themselves today the question of the medicalSupply for this patient circle, that lifelong dependent on kardiologische control investigations is and with that possibly. also line up to RH operations. Only isolated (2004) so far Erwachsenenkardiologen trained themselves further intensively in the area of the innate heart errors. Kinderkardiologen are very competent in the rangethe different disease pictures, however as Pädiater not trained in the range of the Erwachsenkardiologie. Therefore today increasingly interdisciplinary consulting hours in different cardiology centers are offered.
- List of the most frequent heart diseases see to Kardiologie
- innate heart diseases see heart errors and Kinderkardiologie
investigation possibilities of the heart
numbersto heart and heart impact of humans
|Length of the heart||15 cm|
|weight of the heart||300 g|
|impact volume||70 cm 3|
|heart minute volume, in peace||4900 cm 3|
|heart minute volume, large effort||up to 20-30 litres|
|promoted blood quantity in 70 years||of ~180.000.000 litres|
|of workper impact, left chamber||~ 0.8 J|
|of rights chamber||~ 0.16 J|
|daily work of the heart||~ 100,000 J|
|number of the heart impacts in one year (average)||36.000.000|
|number of the heart impacts in 70 years||3.000.000.000|
- “the heart of the organisms is the basic stick of her life, the princetheir everything, which all freshness and Kraft radiate small world sun, on which all life depends. Equally a king is the basic stick its realms and the sun of its small world, the State of heart, from which all power radiates, all gracegoes out. This writing over the movement of the heart I dared to dedicate here to its majesty (like it custom of this time is) all the more, than [...] almost all human acts like also most acts of a king under thatIntuition of the heart carry out themselves. “ of William Harvey: The movement of the heart and the blood (latin expenditure for original of 1628).
Web on the left of
|Wiktionary: Heart - word origin, synonyms and translations|
|Wikiquote: Heart - quotations|
|Wikibooks: Heart - learning and teaching materials|
- 3-dim. Animation striking of the heart with many information
- 2-dim. Animation of the striking heart with diagrams (English)