Embryology of cardiovascular system

The bulbus cordis (the bulb of the heart) lies ventral to the primitive ventricle after the developing heart assumes its S-shaped form.

The primitive atrium is a stage in the embryonic development of the human heart.

The primitive ventricle or embryonic ventricle of the developing heart, together with the bulbus cordis that lies in front of it, gives rise to the left and right ventricles.

The tubular heart or primitive heart tube is the earliest stage of heart development.

The postcardinal veins or posterior cardinal veins join with the corresponding right and left cardinal veins to form the left common cardinal veins, which empty in the sinus venosus.

The placenta (also known as afterbirth) is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, provide thermo-regulation to the fetus, waste elimination, and gas exchange via the mother's blood supply, fight against internal infection and produce hormones to support pregnancy.

In the fetus, the ductus venosus (Arantius' duct after Julius Caesar Aranzi) shunts a portion of the left umbilical vein blood flow directly to the inferior vena cava.

In the fetal heart, the foramen ovale (/fəˈreɪmən oʊˈvæli, -mɛn-, -ˈvɑː-, -ˈveɪ-/), also foramen Botalli, ostium secundum of Born or falx septi, allows blood to enter the left atrium from the right atrium.

In animals that give live birth, the fetal circulation is the circulatory system of a fetus.

The umbilical artery is a paired artery (with one for each half of the body) that is found in the abdominal and pelvic regions.

The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta into the growing fetus.

The vitelline arteries are the arterial counterpart to the vitelline veins.

The interatrial septum is the wall of tissue that separates the right and left atria of the heart.

The anterior cardinal veins (precardinal veins) contribute to the formation of the internal jugular veins and together with the common cardinal vein form the superior vena cava.

The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart.

In the developing fetus, the ductus arteriosus, also called the ductus Botalli, is a blood vessel connecting the pulmonary artery to the proximal descending aorta.

The aortic arches or pharyngeal arch arteries (once referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head.

During development of the veins, the first indication of a parietal system consists in the appearance of two short transverse veins, the ducts of Cuvier (or common cardinal veins), which open, one on either side, into the sinus venosus.

The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast adjacent to the embryonic disk.

The aorticopulmonary septum (also called the spiral septum, or aortic septum in older texts) is developmentally formed from neural crest, specifically the cardiacneural crest, and actively separates the aorta and pulmonary arteries and fuses with the interventricular septum within the heart during heart development.

Each primitive aorta receives anteriorly a vein—the vitelline vein—from the yolk-sac, and is prolonged backward on the lateral aspect of the notochord under the name of the dorsal aorta.

The foramen secundum, or ostium secundum, is a foramen (opening) in the septum primum, a precursor to the interatrial septum of the embryological heart.

In the developing heart, the atria initially communicate with each other by an opening between the free edge of the septum primum and the AV cushions, known as the primary interatrial foramen or ostium primum (interatrial foramen primum), below the free margin of the septum.

During development of the heart, the orifice of the sinus venosus lies obliquely, and is guarded by two halves, the right and left venous valves; above the opening these unite with each other and are continuous with a fold named the septum spurium.

Below the opening of the orifice of the coronary sinus they fuse to form a triangular thickening—the spina vestibuli.

During heart development of a human embryo, the cavity of the primitive atrium becomes subdivided into right and left chambers by a septum, the septum primum, which grows downward into the cavity.

The septum secundum, semilunar in shape, grows downward from the upper wall of the atrium immediately to the right of the primary septum and ostium secundum.

Heart development refers to the prenatal development of the human heart.

Lymph sacs are a part of the development of the human lymphatic system, known as lymphangiogenesis.

The truncus arteriosus is a structure that is present during embryonic development.

In human embryology, the primary interventricular foramen is a temporary opening between the developing ventricles of the heart.

The aortic sac or aortic bulb is a dilated structure in mammalian embryos, lined by endothelial cells located just above (superior to) the truncus arteriosus.

Endocardial cushions, or atrioventricular cushions, refer to a subset of cells in the development of the heart that play a vital role in the proper formation of the heart septa.

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

The vitelline veins are veins which drain blood from the yolk sac.

Blood islands are structures around the developing embryo which lead to many different parts of the circulatory system.