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Intermaxillary Segment
The intermaxillary segment in an embryo is a mass of tissue formed by the merging of tissues in the vicinity of the nose. It is essential for human survival. It is primordial, since in the further development of the embryo this particular mass no longer appears, but parts of it remain in "the intermaxillary portion of the upper jaw, the portion of the upper lip, and the primary palate". More precisely, the rounded lateral angles of the medial process constitute the globular processes. It is also known as the "Intermaxillary segment". It gives rise to the premaxilla. File:Gray45.png, Head end of human embryo of about thirty to thirty-one days. File:Gray46.png, Same embryo as shown in Fig. 45, with front wall of pharynx removed. File:Gray50.png, The roof of the mouth of a human embryo, aged about two and a half months, showing the mode of formation of the palate. File:Gray947.png, The head and neck of a human embryo thirty-two days old, seen from the ventral surface. See a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medial Nasal Prominence
The frontonasal process, or frontonasal prominence is one of the five swellings that develop to form the face. The frontonasal process is unpaired, and the others are the paired maxillary prominences, and the paired mandibular prominences. During the fourth week of embryonic development, an area of thickened ectoderm develops, on each side of the frontonasal process called the nasal placodes or olfactory placodes, and appear immediately under the forebrain. By invagination these areas are converted into two nasal pits, which indent the frontonasal prominence and divide it into medial and lateral nasal processes. Nasal processes The medial nasal process (nasomedial) on the inner side of each nasal pit merge into the intermaxillary segment and form the upper lip, crest, and tip of the nose. The medial nasal processes merge with the maxillary prominences. The lateral nasal process from each side merge to form the alae of the nose. Clinical significance Failure to fuse can cause a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Palate
Around the 5th week, the intermaxillary segment arises as a result of fusion of the two medial nasal processes and the frontonasal process within the embryo. The intermaxillary segment gives rise to the primary palate. The primary palate will form the premaxillary portion of the maxilla (anterior one-third of the final palate). This small portion is anterior to the incisive foramen and will contain the maxillary incisors. References Embryology {{developmental-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Embryo
Human embryonic development or human embryogenesis is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Human fertilization, Fertilization occurs when the Spermatozoon, sperm cell successfully enters and Cell fusion, fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences. Human embryonic development covers the first eight weeks of development, which have 23 stages, called Carnegie stages. At the beginning of the ninth week, the embryo is termed a fetus (spelled "foetus" in British English). In comparison to the embryo, the fetus has more recognizable external features and a more complete set of developing o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nose
A nose is a sensory organ and respiratory structure in vertebrates. It consists of a nasal cavity inside the head, and an external nose on the face. The external nose houses the nostrils, or nares, a pair of tubes providing airflow through the nose for Respiration (physiology), respiration. Where the nostrils pass through the nasal cavity they widen, are known as nasal fossae, and contain nasal concha, turbinates and olfactory mucosa. The nasal cavity also connects to the paranasal sinuses (dead-end air cavities for pressure buffering and humidification). From the nasal cavity, the nostrils continue into the pharynx, a switch track valve connecting the respiratory system, respiratory and digestive systems. In humans, the nose is located centrally on the face and serves as an alternative respiratory passage especially during suckling for infants. The protruding nose that is completely separate from the mouth part is a characteristic found only in theria, therian mammals. It has b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philtrum
The philtrum (, from Ancient Greek , lit. 'love charm') or medial cleft is a vertical indentation in the middle area of the upper lip, common to therian mammals, extending in humans from the nasal septum to the tubercle of the upper lip. Together with a glandular rhinarium and slit-like nostrils, it is believed to constitute the primitive condition for at least therian mammals. Monotremes lack a philtrum, though this could be due to the specialised, beak-like jaws in living species. Function In most mammals, the philtrum is a narrow groove that may carry dissolved odorants from the rhinarium or nose pad to the vomeronasal organ via ducts inside the mouth. For humans and most primates, the philtrum survives only as a vestigial medial depression between the nose and upper lip. The human philtrum, bordered by a pair of ridges known as the ''philtral columns'', is also known as the ''infranasal depression'', but has no apparent function. That may be because most higher pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
