The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta into the growing fetus. The umbilical vein provides convenient access to the central circulation of a neonate for restoration of blood volume and for administration of glucose and drugs.
The celiacartery, also known as the celiac trunk or truncus coeliacus, is the first major branch of the abdominal aorta. It is about 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12) in humans, it is one of three anterior/ midline branches of the abdominal aorta.
The aortic arches or pharyngeal arch arteries are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac.
The inferior mesenteric plexus is derived chiefly from the aortic plexus.
Chorionic villi are villi that sprout from the chorion to provide maximal contact area with maternal blood.
The vitelline veins are veins that drain blood from the yolk sac and the gut tube during gestation.
The dorsal aortae are paired embryological vessels which progress to form the descending aorta. The paired dorsal aortae arise from aortic arches that in turn arise from the aortic sac.
The septum secundum is a muscular flap that is important in heart development. It is semilunar in shape, and grows downward from the upper wall of the atrium immediately to the right of the septum primum and ostium secundum. It is important in the closure of the foramen ovale after birth.
Neuroectoderm consists of cells derived from the ectoderm. Formation of the neuroectoderm is the first step in the development of the nervous system. The neuroectoderm receives bone morphogenetic protein-inhibiting signals from proteins such as noggin, which leads to the development of the nervous system from this tissue. Histologically, these cells are classified as pseudostratified columnar cells.
The aorticopulmonary septum is developmentally formed from neural crest, specifically the cardiac neural crest, and actively separates the aorta and pulmonary arteries and fuses with the interventricular septum within the heart during heart development.
The uncinate process is a small part of the pancreas. The uncinate process is the formed prolongation of the angle of junction of the lower and left lateral borders in the head of the pancreas. The word "uncinate" comes from the Latin "uncinatus", meaning "hooked".
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".
The thalamic fasciculus is a component of the subthalamus. It is synonymous with field H1 of Forel. Nerve fibres form a tract containing cerebellothalamic (crossed) and pallidothalamic (uncrossed) fibres, that is situated between the thalamus and the zona incerta.
The anterior intercostal veins are the veins which drain the anterior intercostal space.
In the development of the human embryo, the intraembryonic coelom is a portion of the conceptus forming in the mesoderm during the third week of development. During the third week of development, the lateral plate mesoderm splits into a dorsal somatic mesoderm (somatopleure) and a ventral splanchnic mesoderm (splanchnopleure). The resulting cavity between the somatopleure and splanchnopleure is called the intraembryonic coelom. This space will give rise to the thoracic and abdominal cavities. The coelomic spaces in the lateral mesoderm and cardiogenic area are isolated. The isolated coelom begins to organize into a horseshoe shape. The spaces soon join together and form a single horseshoe-shaped cavity: the intraembryonic coelom. It then separates the mesoderm into two layers.
The nasal placode gives rise to the olfactory epithelium of the nose. Two nasal placodes arise as thickened ectoderm from the frontonasal process. They give rise to the nose, the philtrum of the upper lip, and the primary palate.
The posterior scrotal veins are veins of the scrotum in men. They accompany the posterior scrotal arteries. They drain into the vesical venous plexus. They help to drain blood from part of the scrotum.
The endocardial tubes are paired regions in the embryo that appear in its ventral pole by the middle of the third week of gestation and consist of precursor cells for the development of the embryonic heart. The endocardial heart tubes derive from the visceral mesoderm and initially are formed by a confluence of angioblastic blood vessels on either side of the embryonic midline. The endocardial tubes have an intimate proximity to the foregut or pharyngeal endoderm.
The umbilical ring is a dense fibrous ring surrounding the umbilicus at birth. At about the sixth week of embryological development, the midgut herniates through the umbilical ring; six weeks later it returns to the abdominal cavity and rotates around the superior mesenteric artery.
