Summary of ✅ PERIODO EMBRIONARIO | DE LA TERCERA A LA OCTAVA SEMANA [2022] 📚 ORGANOGÉNESIS | CAPAS GERMINALES

00:00:00 - 00:25:00

This video provides an overview of the development of the human body during the embryonic period. It discusses the formation of the three germ layers, the development of the nervous system, and the derivatives of the germ layers. It also covers the external aspects of the embryo and the role of programmed cell death in development.

• 00:00:00 The embryonic period is the time during which the three germ layers ectoderm, mesoderm, and endoderm give rise to various tissues and organs in the body. The period of prenatal development is also known as the time during which the embryo is susceptible to teratogenic agents, and during which the embryo is still developing and acquiring greater maturity.
• 00:05:00 This video explains the development of the human body, starting with the third week of development. The neural tube is formed from the ectoderm and the neural plate, which is the layer of cells that separates the ectoderm from the neural tube. The neural tube grows in a cephalo-caudal direction and undergoes a widening, and at the completion of neurulation, the lateral edges rise to form the neural folds and the middle region of the neural plate sinks and originates the neural groove. The neural folds are prominent in the cranial end of the embryo and gradually move toward the midline to fuse and for the neural tube. The fusion begins in the cervical region and continues both cephalad and caudad. As the fusion is completed at the cephalic and caudal ends, the neuropores that communicate with the amnionite cavity are formed. The process of neurulation and the neural tube are completed in development, and the end result is the central nervous system, retina, the pineal gland or epiphyses neurohypophysis, and various other tissues.
• 00:10:00 In this video, the author discusses the beginning of embryology, focusing on the formation of the somites. The somites are segmented into three parts, the sclerotome, myotome, and dermatome, and each part forms bones in the axial skeleton. The intermediate mesoderm connects the paraxial and lateral mesoderm, and it also differentiates into the urogenital structures.
• 00:15:00 The bladder is the only organ in the urogenital system that does not derive from the intermediate mesoderm. The bladder is formed from the lateral mesoderm, which is made up of two layers: the somatic or parietal layer, which is adjacent to the superficial ectoderm, and the layer of the extra-embryonic parietal mesoderm surrounding the amniotic cavity. This parietal layer of the lateral mesoderm together with the overlying ectoderm are called Somatopleura. The visceral layer of the lateral mesoderm together with the underlying endoderm constitute the Splachnopleura. The parietal mesoderm will give rise to the parietal leaves of the peritoneal, pleural and pericardial walls, including the bones of the extremities, the shoulder girdle, the pelvic and the sternum. The splanchnic mesoderm will form the visceral sheets of the peritoneal, pleural and pericardial walls. It will also give rise to the stroma of some viscera, the smooth muscle covering some viscera, to the muscle of the heart, and in the third week, the mesoderm invades the vit
• 00:20:00 The embryo undergoes programmed cell death, and in the process, replaces its blood cells with those of fetal origin. The yolk sac is the first hematopoietic organ of the embryo, and in addition to forming blood cells and capillaries, it also participates in the formation of vasculogenesis and Angiogenesis. Blood vessel formation is mediated by two mechanisms: vasculogenesis, which arises from the endodermal layer, and Angiogenesis, which takes place in the surrounding tissues.
• 00:25:00 This video discusses the derivatives of the germ layers in the human embryo. The ectoderm, neuroectoderm, and mesoderm are each divided into other layers, and the endoderm is not divided into any specific layers. The external aspects of the embryo are also discussed.