tailieunhanh - Introduce about human embryology (Eleventh edition): Part 2

(BQ) Continued part 1, part 2 of the document Introduce about human embryology (Eleventh edition) has contents: Nervous system, endocrine glands, urogenital system, development of eye, cardiovascular system, clinical applications of embryology, embryology ready reckoner, . And other contents. Invite you to refer. | Chapter Face Nose and Palate HIGHLIGHTS The stomatodeum future mouth is a depression bounded cranially by a bulging produced by the brain and caudally by a bulging produced by the pericardial cavity. Three prominences appear around the stomatodeum. These are the frontonasal process above and the right and left mandibular arches first pharyngeal arches The mandibular arch divides into a maxillary process and a mandibular process. The right and left mandibular processes meet in the midline and fuse. They form the lower lip and lower jaw. The upper lip is formed by fusion of the frontonasal process with the right and left maxillary processes. Failure to fuse completely leads to various forms of harelip. The cheeks are formed by fusion of the posterior parts of the maxillary and mandibular processes. The nose is derived from the frontonasal process. The nasal cavity is formed from an ectodermal thickening the nasal placode appears over the frontonasal process. The placode gets depressed below the surface to form the nasal pit. The nasal pits enlarge to form the nasal cavity. Paranasal sinuses appear as outgrowths from the nasal cavity. The palate is formed by fusion of three components. These are the right and left palatal processes arising from the maxillary process and the primitive palate derived from the frontonasal process . Deficiency in fusion leads to various forms of cleft palate. INTRODUCTION During the 4th week of development after the formation of the head fold two prominent bulgings appear on the ventral aspect of the developing embryo separated by the stomatodeum Fig. . They are - Developing brain cranially - Pericardium caudally The floor of the stomatodeum is formed by the buccopharyngeal membrane which separates it from the foregut. On each side the stomatodeum is bounded by first arch. Soon mesoderm covering the developing forebrain proliferates and forms a downward projection that overlaps the upper part of the stomatodeum. This downward .