The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine.
A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid.
The sigmoid colon is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about 35–40 centimetres (14–16 in) in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S. This part of the colon normally lies within the pelvis, but due to its freedom of movement it is liable to be displaced into the abdominal cavity.
Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Since the abdomen contains most of the body's vital organs, it can be an indicator of a wide variety of diseases. Given that, approaching the examination of a person and planning of a differential diagnosis is extremely important.
The hindgut is the posterior (caudal) part of the alimentary canal. In mammals, it includes the distal one third of the transverse colon and the splenic flexure, the descending colon, sigmoid colon and up to the ano-rectal junction. In zoology, the term hindgut refers also to the cecum and ascending colon.
In human anatomy, the mesentery, an organ that attaches the intestines to the posterior abdominal wall, comprises the double fold of the peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines.
A Meckel's diverticulum, a true congenital diverticulum, is a slight bulge in the small intestine present at birth and a vestigial remnant of the vitelline duct. It is the most common malformation of the gastrointestinal tract and is present in approximately 2% of the population, with males more frequently experiencing symptoms.
An omphalocele or omphalocoele, also known as an exomphalos, is a rare abdominal wall defect. Beginning at the 6th week of development, rapid elongation of the gut and increased liver size reduces intra abdominal space, which pushes intestinal loops out of the abdominal cavity. Around 10th week, the intestine returns to the abdominal cavity and the process is completed by the 12th week. Persistence of intestine or the presence of other abdominal viscera in the umbilical cord results in an omphalocele.
In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta.
Gastroschisis is a birth defect in which the baby's intestines extend outside of the abdomen through a hole next to the belly button. The size of the hole is variable, and other organs including the stomach and liver may also occur outside the baby's body. Complications may include feeding problems, prematurity, intestinal atresia, and intrauterine growth restriction.
A pulmonary sequestration is a medical condition wherein a piece of tissue that ultimately develops into lung tissue is not attached to the pulmonary arterial blood supply, as is the case in normally developing lung. This sequestered tissue is therefore not connected to the normal bronchial airway architecture, and fails to function in, and contribute to, respiration of the organism.
Intestinal malrotation is a congenital anomaly of rotation of the midgut. It occurs during the first trimester as the fetal gut undergoes a complex series of growth and development. Malrotation can lead to a dangerous complication called volvulus, in which cases emergency surgery is indicated. Malrotation can refer to a spectrum of abnormal intestinal positioning, often including:
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.
In human anatomy, the inferior mesenteric artery (IMA) is the third main branch of the abdominal aorta and arises at the level of L3, supplying the large intestine from the distal transverse colon to the upper part of the anal canal. The regions supplied by the IMA are the descending colon, the sigmoid colon, and part of the rectum.
The foregut in humans is the anterior part of the alimentary canal, from the distal esophagus to the first half of the duodenum, at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. The foregut arises from the endoderm, developing from the folding primitive gut, and is developmentally distinct from the midgut and hindgut. Although the term “foregut” is typically used in reference to the anterior section of the primitive gut, components of the adult gut can also be described with this designation. Pain in the epigastric region, just below the intersection of the ribs, typically refers to structures in the adult foregut.
The superior mesenteric ganglion is a ganglion in the upper part of the superior mesenteric plexus. It lies close to the origin of the superior mesenteric artery.
The following outline is provided as an overview of and topical guide to human anatomy:
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.
The development of the digestive system in the human embryo concerns the epithelium of the digestive system and the parenchyma of its derivatives, which originate from the endoderm. Connective tissue, muscular components, and peritoneal components originate in the mesoderm. Different regions of the gut tube such as the esophagus, stomach, duodenum, etc. are specified by a retinoic acid gradient that causes transcription factors unique to each region to be expressed. Differentiation of the gut and its derivatives depends upon reciprocal interactions between the gut endoderm and its surrounding mesoderm. Hox genes in the mesoderm are induced by a Hedgehog signaling pathway secreted by gut endoderm and regulate the craniocaudal organization of the gut and its derivatives. The gut system extends from the oropharyngeal membrane to the cloacal membrane and is divided into the foregut, midgut, and hindgut.
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. The heart is the first functional organ in vertebrate embryos.
