Question
The cardiogenic area is formed in the:
| A. |
Extraembryonic mesoderm |
| B. |
Somatopleuric mesoderm |
| C. |
Splanchnopleuric mesoderm |
| D. |
Paraxial mesoderm |
Show Answer
|
Correct Answer � C Explanation |
 |
Heart development
- Heart development (also known as cardiogenesis) refers to the prenatal development of the heart.
- This begins with the formation of two endocardial tubes which merge to form the tubular heart, also called the primitive heart tube.
Early development
- The heart derives from embryonic mesodermal germ layer cells that differentiate after gastrulation into mesothelium, endothelium, and myocardium.
- Mesothelial pericardium forms the outer lining of the heart.
- The inner lining of the heart – the endocardium, lymphatic and blood vessels, develop from endothelium.
Endocardial tubes
- In the splanchnopleuric mesenchyme on either side of the neural plate, a horseshoe-shaped area develops as the cardiogenic region. This has formed from cardiac myoblasts and blood islands as forerunners of blood cells and vessels.
- By day 19, an endocardial tube begins to develop in each side of this region. These two tubes grow and by the third week have converged towards each other to merge, using programmed cell death to form a single tube, the tubular heart.
- From splanchnopleuric mesenchyme, the cardiogenic region develops cranially and laterally to the neural plate.
Heart tube position
- The central part of cardiogenic area is in front of the oropharyngeal membrane and the neural plate.
- The growth of the brain and the cephalic folds push the oropharyngeal membrane forward, while the heart and the pericardial cavity move first to the cervical region and then into the chest.