The cardiovascular system is a system of organs that ensures the delivery of substances necessary for vital activity to all cells and tissues of the human body.
It consists of three components:
- Heart (cor in Latin), which acts as a kind of pump for blood
- Vessels (vasa), which perform a transport function by distributing blood throughout the body
- And blood itself, which contains oxygen, as well as nutrients.
In this video, we will focus in detail on the structure of the heart.
The heart is a large cone-shaped muscular organ, which lies in the thoracic cavity in the mediastinum, mainly on the left.
The work of the heart continuously provides the entire body with nutrients and oxygen. This is due to the constant contraction of the cells that make up the walls of the heart called cardiomyocytes. It should be noted that there are two types of cardiomyocytes:
1. Typical, working cardiomyocytes that contract mechanically under the influence of electrical impulses
and
2. Atypical cardiomyocytes. They generate and conduct nerve impulses. Such cardiomyocytes form the so-called conducting system of the heart.
The sequential contraction of the myocardium forms the cardiac cycle. Proper operation of the phases of this cycle is necessary for the nutrition of every cell of our body.
The human heart has four cavities, which are called chambers.
These are the left atrium (atrium sinistrum)
The left ventricle (ventriculus sinister)
Right atrium (atrium dextrum)
Right ventricle (ventriculus dexter)
The right ventricle and left atrium are components of the pulmonary circulation, and the left ventricle and right atrium are components of the systemic circulation.
Let’s consider the external structure of the heart
It has the following surfaces:
1) Anterior one is the sternocostal surface (facies sternocostalis)
2) The inferior one is the diaphragmatic surface (facies diaphragmatica)
3) The lateral ones are the pulmonary surfaces (facies pulmonalis), right and left
4) The base of the heart (basis cordis)
5) The apex of the heart (apex cordis)
There are depressions or sulci on the surfaces of the heart:
1) The coronary sulcus (sulcus coronarius), which is located between the atria and ventricles.
2) The anterior interventricular sulcus (sulcus intraventricularis anterior)
3) The posterior (inferior) interventricular sulcus (sulcus interventricularis posterior)
4) The notch of the cardiac apex (incisura apicis cordis), which communicate the anterior and posterior interventricular sulci between each other.
On the outside, the heart is covered with the so-called pericardium (pericardium)
The heart wall consists of three layers:
-
Epicardium (epicardium)
-
Myocardium (myocardium)
-
Endocardium (endocardium)
The epicardium is the external fibrous capsule of the heart, the initial parts of the pulmonary trunk and aorta, and the final parts of the pulmonary veins and venae cavae. It passes into the serous pericardium.
The myocardium is the middle muscle layer. The atrial myocardium is separated from the ventricular myocardium.
The atrial myocardium consists of two layers:
The superficial layer consists of circularly arranged fibers
The deep layer consists of longitudinally arranged fibers
The ventricular myocardium consists of three layers:
The superficial layer consists of longitudinally arranged fibers, and forms a helix (vortex cordis) at the apex of the heart
The middle layer consists of circularly arranged fibers
The internal layer consists of longitudinally arranged fibers
The endocardium is the internal layer of the heart, which covers the papillary and pectinate muscles, chords and valves.
The heart also has a skeleton of sorts, which is called the fibrous skeleton of the heart and includes the following structures:
-
Right anulus fibrosus (anulus fibrosus dexter)
-
Left anulus fibrosus (anulus fibrosus sinister)
Located in the projection of the coronary sulcus
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The anulus fibrosus of the aorta (anulus fibrosus aortae)
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The anulus fibrosus of the pulmonary trunk (anulus fibrosus trunci pulmonalis)
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The right fibrous trigone (trigonum fibrosum dexter)
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The left fibrous trigone (trigonum fibrosum sinister)
In the right fibrous trigone, there is an opening through which the fibers of the conductive system of the heart pass
Let’s consider each of the four chambers of the heart in greater detail.
The right atrium (atrium dextrum) has an additional cavity called the right auricle (auricula dextra).
From the inferior side, it is delimited by the right atrioventricular orifice (ostium atrioventiculare dextrum) and the tricuspid valve (valva tricuspidalis), through which venous blood enters the right ventricle.
The interatrial septum (septum interatriale), on the surface of which there is an oval fossa (fossa ovalis), is a border between the right and left atria.
The superior and inferior vena cava (vena cava inferior et vena cava superior) end by the right atrium in the area of the sinus of venae cavae (sinus venarum cavarum).
There is a coronary sinus (sinus coronarius) of the heart between them.
In the area of the confluence of the inferior vena cava there is a valve of the inferior vena cava (valvula venae cavae inferioris), at the same level there is a valve of the coronary sinus (valvula sinus coronarii).
On the internal surface of the right auricle and partially the anterior wall of the atrium, there are pectinate muscles (mm. pectinati).
The right ventricle (ventriculus dexter) is separated from the left one by the interventricular septum (septum interventriculare).
In the right ventricle, there is an opening of the pulmonary trunk (ostium trunci pulmonalis). Venous blood enters the lungs through the pulmonary trunk.
There is a tricuspid valve (valva tricuspidalis) between the superior and inferior chambers of the right half of the heart. It regulates the flow and release of blood in this part of the heart. Let’s consider it’s structure in greater detail.
The right atrioventricular (tricuspid) valve (valva atrioventricularis dextra / valva tricuspidalis) consists of:
1. The anulus fibrosus (annulus fibrosus)
2. Anterior, posterior, and septal cusps (cuspis anterior, cuspis posterior, cuspis septalis),
which are covered with endocardium
3. Tendinous chords, which are are attached to the three papillary muscles holding the valve cusps.
4. Between the papillary muscles, there are trabeculae carneae (trabeculae carneae)
The pulmonary trunk (truncus pulmonalis) arises from the right ventricle in the area of the conus arteriosus (conus arteriosus). It is also separated from the ventricular cavity by a valve.
The pulmonary valve (valva trunci pulmonalis) consists of:
1. The anulus fibrosus (annulus fibrosus)
2. The left semilunar cusp, right semilunar cusp and anterior semilunar cusp (valvae semilunares)
3. Nodules of the semilunar cusps
4. Sinuses of the pulmonary trunk (lunulae valvularum semilunarium)
The left half of the heart has similar structural features. Let’s consider it in greater detail.The left atrium (atrium sinistrum), just like the right one, has an additional cavity called the left auricle (auricula sinistra). Pectinate muscles are present on the internal surface of the auricle.
From the inferior side, the atrium is delimited by the left atrioventricular orifice (ostium atrioventriculare sinistrum) and the left atrioventricular (bicuspid or mitral) valve (valva atrioventricularis sinistra (mitralis)).
Four pulmonary veins (venae pulmonalis) end by the cavity of the left atrium.
The left ventricle (ventriculus sinister) is located below the atrium.
The left ventricle is the largest chamber of the heart. Its wall is the thickest, and its contraction provides a large volume of blood discharge into the aorta, which is the largest artery of our body.
Let’s consider the structure of the left atrioventricular (bicuspid or mitral) valve (valva atrioventricularis sinistra (mitralis)). It consists of:
1. The anulus fibrosus (annulus fibrosus)
2. The anterior and posterior cusps (cuspis anterior et posterior), which are covered with the endocardium
3. The tendinous chords (chordae tendineae), which are attached to two papillary muscles (mm. papillares) holding the valve cusps.
4. The trabeculae carneae (trabeculae carneae), which are located between the papillary muscles.
The aorta (aorta), which also has its own valve (valva aortae), arises from the left ventricle in the area of the aortic orifice (ostium aortae).
It consists of the following structures:
1. The anulus fibrosus (annulus fibrosus)
2. The right semilunar cusp, posterior semilunar cusp, and left semilunar cusp (valvulae semilunares dextra, posterior et sinistra)
3. Nodules of the semilunar cusps
4. Sinuses of Valsalva or aortic sinuses (sinus aortae in Latin)
The right and left halves of the heart are separated from each other and normally do not communicate in any way. There is an interventricular septum between the ventricles, which has two parts:
The muscular part (pars muscularis)
The membranous part (pars membranacea)
Anatomy of the heart. Heart valves
- Heart
- cor
- Sternocostal surface
- facies sternocostalis
- Diaphragmatic surface
- facies diaphragmatica
- Pulmonary surface
- facies pulmonalis
- Base of the heart
- basis cordis
- Apex of the heart
- apex cordis
- Coronary sulcus
- sulcus coronarius
- Anterior interventricular sulcus
- sulcus intraventricularis anterior
- Posterior interventricular sulcus
- sulcus interventricularis posterior
- Notch of the cardiac apex
- incisura apicis cordis
- Epicardium
- epicardium
- Myocardium
- myocardium
- Vortex of the heart
- vortex cordis
- Endocardium
- endocardium
- Right and left anulusfibrosus
- anuli fibrosi dexter et sinister
- Connective tissue rings of the aorta and pulmonary trunk
- anuli fibrosi aortae et truncipulmonalis
- Right fibrous trigone
- trigonum fibrosum dexter
- Left fibrous trigone
- trigonum fibrosum sinister
- Right atrium
- atrium dextrum
- Right auricle
- auricula dextra
- Right atrioventricularorifice
- ostium atrioventiculare dextrum
- Tricuspid valve
- valva tricuspidalis
- Interatrial septum
- septum interatriale
- Fossa ovalis
- fossa ovalis
- Sinus of venae cavae
- sinus venarum cavarum
- Superior vena cava
- vena cava superior
- Inferior vena cava
- vena cava inferior
- Intervenous tubercle
- tubrerculum intervenrosum
- Coronary sinus of the heart
- sinus coronarius
- Valve of the inferior vena cava
- valvula venae cavae inferioris
- Valve of the coronary sinus
- valvula sinus coronarii
- Musculi pectinati
- mm. pectinati
- Right ventricle
- ventriculus dexter
- Interventricular septum
- septum interventriculare
- Opening of the pulmonary trunk
- ostium truncipulmonalis
- Right atrioventricular valve
- valva atrioventricularis dextra
- Anterior cusp
- cuspis anterior
- Posterior cusp
- cuspis posterior
- Septal cusp
- cuspis septalis
- Trabeculae carneae
- trabeculae carneae
- Conus arteriosus
- conus arteriosus
- Pulmonary trunk
- truncus pulmonalis
- Pulmonary valve
- valva trunci pulmonalis
- Left semilunar cusp
- valvula semilunaris sinistra
- Right semilunar cusp
- valvula semilunaris dextra
- Anterior semilunar cusp
- valvula semilunaris anterior
- Sinuses of the pulmonary trunk
- lunulae valvularumsemilunarium
- Left atrium
- atrium sinistrum
- Left auricle
- auricula sinistra
- Left atrioventricularorifice
- ostium atrioventriculare sinistrum
- Left atrioventricularvalve
- valva atrioventricularis sinistra
- Anterior cusp
- cuspis anterior
- Posterior cusp
- cuspis posterior
- Pulmonary veins
- venae pulmonales
- Left ventricle
- ventriculus sinister
- Aortic orifice
- ostium aortae
- Aorta
- aorta
- Aortic valve
- valva aortae
- Right semilunar cusp
- valvula semilunaris dextra
- Posterior semilunarcusp
- valvula semilunaris posterior
- Left semilunar cusp
- valvula semilunaris sinistra
- Aortic sinus
- sinus aortae
- Muscular part
- pars muscularis
- Membranous part
- pars membranacea