Embriologia do coração.

Summary

In this educational video, Verônica explains the embryology of the heart, covering its development from the third week of embryonic life. She discusses how the cardiovascular system forms, with a focus on the heart’s early tubular structure and its transformation into a complex organ. Key topics include heart septation, the development of atrioventricular valves, the separation of the atria, and the formation of the interventricular septum. Verônica also explores the fetal and neonatal circulatory systems, emphasizing the importance of the foramen ovale in fetal development. She concludes with a comparison of fetal and neonatal circulation and references essential textbooks for further study.

Takeaways

• 😀 The heart begins its embryological development in the third week, making it one of the first systems to form.
• 😀 By the 21st day of development, the heart starts beating, although initially ineffective, and by the 24th day, it develops rhythmic contractions.
• 😀 The heart starts as a simple tubular structure, which later undergoes folding and septation to form the adult heart's chambers.
• 😀 The cardiovascular system, including the heart and blood vessels, is crucial for nutrient delivery to all developing systems in the embryo.
• 😀 The heart's initial tubular structure undergoes folding, with the bulbus and primitive ventricle moving forward, while the atria and venous sinus move backward.
• 😀 The heart undergoes septation, leading to the division of the heart into right and left atria, right and left ventricles, and the division of the bulbus into the aorta and pulmonary trunk.
• 😀 The atrioventricular septation occurs through the formation of endocardial cushions, which lead to the creation of the mitral and tricuspid valves.
• 😀 The septation of the primitive atrium divides it into the right and left atria, with an important feature being the foramen ovale, which allows blood flow between the atria in the fetus.
• 😀 The interventricular septum is formed from a combination of muscular and membranous components, with contributions from the median muscular crest and endocardial cushions.
• 😀 The separation of the bulbus cordis and primitive ventricle forms the aorta and pulmonary trunk, which are crucial for systemic and pulmonary circulation, respectively.
• 😀 In fetal circulation, the placenta is responsible for oxygenating the blood, which passes through the foramen ovale from the right atrium to the left atrium, bypassing the lungs.

Q & A

What is the primary function of the cardiovascular system during embryonic development?

The cardiovascular system, which includes the heart, plays a crucial role in transporting nutrients and oxygen to all developing systems, making it one of the first systems to form in the embryo.

At what point in embryonic development does the heart start beating?

The heart begins its beating, albeit weakly, at 21 days of development and starts rhythmic, stronger contractions by 24 days.

How does the heart's structure change during early development?

Initially, the heart starts as a tubular structure that undergoes folding and twisting to eventually form the recognizable heart with distinct atria and ventricles.

When do the two endocardial tubes fuse during embryonic heart development?

The two endocardial tubes fuse during the fourth week of development, forming a single heart tube that will evolve into the adult heart.

What are the key dilations in the primitive heart tube, and what do they become?

The key dilations in the primitive heart tube are the bulbus cordis, primitive atrium, primitive ventricle, and sinus venosus. These dilations will later develop into the adult heart's chambers.

How does the folding of the heart tube affect its development?

The folding of the heart tube causes the bulbus cordis and primitive ventricle to shift forward and downward, while the primitive atrium and sinus venosus move backward and upward. This rearranges the heart's structure to resemble the adult heart.

What is cardiac septation, and why is it important?

Cardiac septation refers to the division of the heart into distinct chambers and vessels, including the atria and ventricles. This process is essential to ensure proper circulation and prevent mixing of oxygen-rich and oxygen-poor blood.

What are the key steps in the atrioventricular septation process?

Atrioventricular septation occurs through the formation of endocardial cushions, which divide the primitive atrioventricular canal and eventually form the atrioventricular valves, including the mitral and tricuspid valves.

How does the formation of the foramen ovale contribute to fetal circulation?

The foramen ovale allows oxygen-rich blood from the right atrium to pass directly into the left atrium, bypassing the non-functional fetal lungs, ensuring that oxygenated blood reaches vital organs.

What happens to the foramen ovale after birth?

After birth, the closure of the foramen ovale occurs due to increased pressure in the left atrium, preventing the passage of blood between the atria. This closure is complete by the first year of life.