What are the heart development phases?
There are five main phases of heart development. The first is the development of a primitive heart tube in which the heart begins to beat. The second is the phase of the heart loop where the form of the heart begins to shape. The third means the development of two separate heart chambers. The fourth and fifth phases appear when the third and fourth heart chambers are formed. The whole heart development takes about eight weeks.
The first phase of heart development includes a primitive heart tube. It consists of a single heart tube that is formed when the cells of heart precursors are connected together. In this early phase, although it seems to be just a tube, the heart consists of different areas and layers. The regions are cranial, caudal and bulbs that develop to form aorta, the largest artery in the human body and the chamber. The layers are heart jelly and the layers of the heart mantle will form myometrium and epicardiumsrdce.
The heart begins to beat during the first phase of heart development. Usually during the fifth week of pregnancy, about 22 or 23 days after conception, the vaginal ultrasound can beTo see a small flashing heart rhythm. This very primitive but functional heart -shaped heart is close to the similarity to the fish heart.
The second phase of heart development occurs quickly, within 24 hours. It's called a heart loop. As it grows, the tube-shaped heart is twisted into S-shaped and bends to the right, called a D-Smy. This new shape creates a primitive area for the chamber growth. This phase of development is induced by activated proteins specific to the heart.
Another phase of heart development is called a two -chamber phase. Two chambers consist of one atrium and one chamber. During this phase of the heart, it continues to grow quickly. The heart jelly serves as a valve between the chamber area and the atrium. The two -chamber stage of the growing human heart resembles the heart of the frog.
The fourth phase of heart development is caused by the dividing of the atrie. This phase is called a three -chamber heart. Three chambers include two atriums that divided,which rest at the top of the chamber, the third chamber. This phase of the developing heart looks like a three -chamber snake or a turtle heart.
The last phase of heart development occurs until the end of the tenth week of pregnancy. This is marked by the development of the fourth heart chamber. The heart is now fully created by two atriums, two chambers and two large blood vessels that transmit blood to and from the heart.