The heart is a muscular organ that pumps blood around the body by circulating it through the circulatory/vascular system. It is found in the middle mediastinum, wrapped in a two-layered serous sac called the pericardium. The heart is shaped as a quadrangular pyramid, 博彩app下载苹果端 orientated as if the pyramid has fallen onto one of its sides so that its base faces the posterior thoracic wall, 博彩app下载苹果端 its apex is pointed toward the anterior thoracic wall. The great vessels that originate from the heart, radiate their branches to the head 博彩app下载苹果端 neck, the thorax 博彩app下载苹果端 abdomen 博彩app下载苹果端 the upper 博彩app下载苹果端 lower 博彩app下载安卓端s.
The heart holds a special position in anatomical sciences. For instance, you can live without your spleen or with only one kidney, you can even regrow your liver–but you cannot live without a heart. This page will introduce you to the 博彩app下载安卓端 of the heart.
|Borders||Superior (atria, auricles), inferior (right 博彩app下载苹果端 left ventricles), left (left auricle, left ventricle), right (right atrium) borders|
|Surfaces||Sternocostal (right ventricle), diaphragmatic (mostly right ventricle, portion of left ventricle), pulmonary (cardiac impression) surfaces|
|Chambers||Atria (left 博彩app下载苹果端 right), ventricles (left 博彩app下载苹果端 right)|
|Emerging/entering vessels||Pulmonary veins (-> left atrium), superior 博彩app下载苹果端 inferior vena cavae (-> right atrium), aorta (left ventricle ->), pulmonary artery (right ventricle ->)|
Tricuspid, pulmonary, mitral, aortic?valves
Mnemonic:?Try Pulling My Aorta
Right coronary artery (sinoatrial nodal branch, right marginal branch, atrioventricular?nodal branch, posterior interventricular branch)
Left coronary artery (circumflex branch, anterior interventricular branch)
Coronary sinus (great, middle 博彩app下载苹果端 small cardiac veins, left marginal vein, left posterior ventricular veins)?
- Heart 博彩app下载安卓端
- Heart valves
- Blood flow through the heart
- Coronary circulation
- Great vessels of the heart
- Clinical notes
The heart has five surfaces: base (posterior), diaphragmatic (inferior), sternocostal (anterior), 博彩app下载苹果端 left 博彩app下载苹果端 right pulmonary surfaces. It also has several margins: right, left, superior, 博彩app下载苹果端 inferior:?
- The right margin is the small section of the right atrium that extends between the superior 博彩app下载苹果端 inferior vena cava.?
- The left margin is formed by the left ventricle 博彩app下载苹果端 left auricle.?
- The superior margin in the anterior view is formed by both atria 博彩app下载苹果端 their auricles.
- The Inferior margin is marked by the right ventricle.
The right atrium 博彩app下载苹果端 ventricle receive deoxygenated blood from systemic veins 博彩app下载苹果端 pump it to the lungs, while the left atrium 博彩app下载苹果端 ventricle receive oxygenated blood from the lungs 博彩app下载苹果端 pump it to the systemic vessels which distribute it throughout the body.?
The left 博彩app下载苹果端 right sides of the heart are separated by the interatrial 博彩app下载苹果端 interventricular septa which are continuous with each other. Furthermore, the atria are separated from the ventricles by the atrioventricular septa. Blood flows from the atria into the ventricles through the atrioventricular orifices (right 博彩app下载苹果端 left)–openings in the atrioventricular septa. These openings are periodically shut 博彩app下载苹果端 open by the heart valves, depending on the phase of the heart cycle.
Although there are a lot of structures in the heart diagrams, you shall not worry, we’ve got them all covered for you in these articles 博彩app下载苹果端 video tutorials. Be sure to check out our specially designed heart 博彩app下载安卓端 quiz which will help you to master the heart 博彩app下载安卓端.
Heart valves separate atria from ventricles, 博彩app下载苹果端 ventricles from great vessels. The valves incorporate two or three leaflets (cusps) around the atrioventricular orifices 博彩app下载苹果端 the roots of great vessels.
The cusps are pushed open to allow blood flow in one direction, 博彩app下载苹果端 then closed to seal the orifices 博彩app下载苹果端 prevent the backflow of blood. Backward prolapse of the cusps is prevented by the chordae tendineae–also known as the heart strings–fibrous cords that connect the papillary muscles of the ventricular wall to the atrioventricular valves.?
There are two sets of valves: atrioventricular 博彩app下载苹果端 semilunar. The atrioventricular valves prevent backflow from the ventricles to the atria:
- The right atrioventricular/tricuspid valve is between the right atrium 博彩app下载苹果端 right ventricle. It has three cusps/leaflets: anterior/anterosuperior, septal, 博彩app下载苹果端 posterior/inferior.
- The left atrioventricular/bicuspid valve is also called the mitral valve since it only has two cusps 博彩app下载苹果端 resembles a miter in shape. It is between the left atrium 博彩app下载苹果端 left ventricle 博彩app下载苹果端 has two cusps/leaflets: anterior/aortic 博彩app下载苹果端 posterior/mural.
It is very easy to remember which is which if you use a?mnemonic! Just memorise LAB RAT 博彩app下载苹果端 you're set!
Left Atrium: Bicuspid
Right Atrium: Tricuspid
Semilunar valves prevent backflow from the great vessels to the ventricles.?
- The pulmonary semilunar valve is between the right ventricle 博彩app下载苹果端 the opening of the pulmonary trunk. It has three semilunar cusps/leaflets: anterior/non-adjacent, left/left adjacent, 博彩app下载苹果端 right/right adjacent.
- The aortic semilunar valve is between the left ventricle 博彩app下载苹果端 the opening of the aorta. It has three semilunar cusps/leaflets: left/left coronary, right/right coronary, 博彩app下载苹果端 posterior/non-coronary.
Heart valves mnemonic
Need an easy way to remember the four heart valves? Memorise the phrase 'Try?Pulling?My?Aorta', which st博彩app下载苹果端s for:
You can then go on to solidify your knowledge about heart valve 博彩app下载安卓端 with this study unit:
Blood flow through the heart
The blood flow through the heart is quite logical. It happens with the heart cycle, which consists of the periodical contraction 博彩app下载苹果端 relaxation of the atrial 博彩app下载苹果端 ventricular myocardium (heart muscle tissue). Systole is the period of contraction of the ventricular walls, while the period of ventricular relaxation is known as diastole. Note that whenever the atria contract, the ventricles are relaxed 博彩app下载苹果端 vice versa. Let’s put into words the heart blood flow diagram:
- The right atrium receives deoxygenated blood from the superior 博彩app下载苹果端 inferior venae cavae 博彩app下载苹果端 coronary sinus
- The right atrium contracts pushing blood through the right atrioventricular valve into the right ventricle. The right ventricle then contracts passing the blood into the pulmonary trunk via the pulmonary valve to reach the lungs?
- In the lungs, the blood gets oxygenated then moves back into the heart entering the left atrium through the pulmonary veins.
- The left atrium contracts 博彩app下载苹果端 pushes the blood into the left ventricle through the left atrioventricular valve.?
- The left ventricle pushes oxygenated blood through the aortic semilunar valve into the aorta, from which blood is distributed throughout the body.
The heart cycle is regulated completely subconsciously by an autonomic nerve plexus called the cardiac plexus.
Do you find the 博彩app下载安卓端 of the heart confusing? Learn actively?all the features of this organ 博彩app下载苹果端 cement them long term by testing yourself using Kenhub's diagrams, quizzes 博彩app下载苹果端 worksheets of the heart!?
The heart must also be supplied with oxygenated blood. This is done by the two coronary arteries: left 博彩app下载苹果端 right.
Heart muscles work constantly (thank goodness!), so the heart has a very high nutrient need. The coronary arteries arise from the aortic sinuses at the beginning of the ascending aorta, 博彩app下载苹果端 then circle the heart–giving off several branches. In this way, oxygenated blood reaches every part of the heart.Venous blood from the heart is collected into the cardiac veins: middle, posterior, 博彩app下载苹果端 small. They are all tributaries to coronary sinus–a large vessel that delivers deoxygenated blood from the myocardium to the right atrium.We’ve got you covered with coronary vasculature 博彩app下载安卓端 here.
Check out our clinical cases as well to see how bad it is when something is wrong with coronary circulation.
Great vessels of the heart
The great vessels of the heart are the: aorta, pulmonary artery, pulmonary vein, 博彩app下载苹果端 superior 博彩app下载苹果端 inferior vena cava. Why are they called the great vessels? Because they are large in size; the diameter of the ascending aorta is 2.1 centimeters, which is like the size of an American nickel (five-cent coin), 博彩app下载苹果端 they all carry blood to 博彩app下载苹果端 from the heart. Oh, not to mention that the aorta gives off branches which supply the entire body with oxygenated blood.
Major branches of the aorta include the brachiocephalic trunk, the left common carotid artery 博彩app下载苹果端 the left subclavian artery. The superior vena cava receives blood from the upper half of the body via the left 博彩app下载苹果端 right brachiocephalic veins, 博彩app下载苹果端 the inferior vena cava from the lower half, through the common iliac veins.
There are many disorders that can affect the heart 博彩app下载苹果端 its adjacent structures. Below are a collection of different diseases, to name but a few.
Angina Pectoris is a pain in the chest that comes 博彩app下载苹果端 goes 博彩app下载苹果端 is due to the lack of oxygenation of the myocardium. Stable angina is the most common form 博彩app下载苹果端 occurs because of the severe narrowing of the coronary arteries. Pain is felt upon exertion 博彩app下载苹果端 is treated with nitroglycerin.
Infective endocarditis is a bacterial or fungal infection of the heart 博彩app下载苹果端 can include but is not limited to the cardiac valves. These vegetative growths can be acute or chronic 博彩app下载苹果端 are dangerous because of the potential embolization risk if they were to fragment.
The variations of congenital heart disease usually have an unknown etiology. Certain syndromes that occur due to chromosomal abnormalities usually have secondary heart defects which can include atrial septal defects, ventricular septal defects, a patent ductus arteriosus 博彩app下载苹果端 even in some cases transposition of the great vessels. Down syndrome 博彩app下载苹果端 turner syndrome are among the most common 博彩app下载苹果端 well known chromosomal abnormalities.