✅ EMBRIOLOGÍA CARDIOVASCULAR 💉🧡
Embryology of the Cardiovascular System
This section delves into the embryological development of the cardiovascular system, focusing on the formation of the heart, its partitioning, and the origin of its conducting system.
Formation of Heart Cells
- : During the third week of embryo growth, heart cells migrate from the epiblast to form a primary cardiogenic field (CPC) that contributes to regions of the atria and left ventricle.
- : The right ventricle and outflow tract derive from the secondary cardiogenic field (CCS), integrating with other heart regions for complete development.
Cardiogenic Region Development
- : Induction by pharyngeal endoderm leads to cardiac myoblast and blood islet formation, initiating vasculogenesis within the cardiogenic region.
- : As neural tube closure occurs, brain growth influences heart positioning from cervical to thoracic levels through cephalic folding.
Heart Tube Formation
- : The central region expands to form future exit tracts and ventricular areas, transforming into a continuous dilated tube with endothelial lining and myocardial layer.
- : Venous drainage at caudal pole initiates blood pumping towards dorsal aorta while mesodermal tissue connects heart to pericardial cavity.
Continuation: Cardiovascular System Development
This section explores further developments in cardiovascular system formation including myocardium thickening, extracellular matrix secretion, and epicardial layer formation.
Myocardium Maturation
- : Thickening myocardium secretes hyaluronic acid-rich extracellular matrix while proepicardial organ forms epicardial layer over myocardium surface.
- : Three layers compose heart tube - Endocardium for inner lining, Myocardium as muscular wall, Epicardium covering exterior responsible for coronary artery formation.
Growth Process
- : Continuous growth adds CCS cells at cranial end essential for normal right ventricle integration and outflow tract development.
Understanding Cardiac Development
This section delves into the development of the cardiac system, focusing on the formation of various structures like the arterial cone and trunk, umbilical vein, common cardinal vein, and septums within the heart.
Formation of Venous System
- The arterial cone and trunk derive from the secondary cardiogenic field.
- Changes occur in venous circulation during weeks four and five of development due to short circuits.
- Obliteration of veins leads to changes in venous sinus structure by week five.
- Increased dimensions of right breast veins due to left-right blood flow alterations.
Development of Atrial Structures
- Valves fuse to form Septo Espurio ridge aiding in atrial septum formation.
- Cardiac partitions form between days 27 and 37 through active growth mechanisms.
Atrioventricular Separation
- Septum primum formation initiates separation between atria at week four.
- Cell death leads to Ostium Primum formation for blood passage between atria.
Arterial Trunk Development
- Arterial trunk ridges spiral to position aorta and pulmonary arteries by week five.
- Fusion of frustoconal ridges forms anterolateral canal for right ventricular outflow tract.
Development of Ventricles and Cardiac Conduction System
This section discusses the development of ventricles in the heart, focusing on the expansion of primitive ventricles and the formation of the interventricular septum. Additionally, it explores the cardiac conduction system's initial stages, including pacemaker activity and node formation.
Development of Ventricles
- The two primitive ventricles begin to expand through continuous growth of myocardium.
- Expansion involves continuous generation of diverticula and trabeculae internally while medial walls merge to form the muscular portion of the interventricular septum.
- Closure of interventricular foramen occurs with membranous ventricle intervention in septum formation, aided by tissue growth along the top of muscular septum.
- Truncal ridges' growth and endocardial pads lead to closure of ventricular foramen, forming membranous portion interventricular septum.
Cardiac Conduction System Development
- Initially, all myocardial cells exhibit pacemaker activity around 21 days gestation before restricting to left caudal region; later assumed by venous sinus.
- Sinoauricular Node (SA) forms near superior vena cava drainage hole as pacemaker tissue incorporates into right atrium.