DuodenumThe duodenum (duː'wɑːdɪnəm , duːoʊ'diːnəm ) 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. In humans, the duodenum is a hollow jointed tube about long connecting the stomach to the middle part of the small intestine. It begins with the duodenal bulb and ends at the suspensory muscle of duodenum.
JejunumThe jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialized for the absorption by enterocytes of small nutrient molecules which have been previously digested by enzymes in the duodenum. The jejunum lies between the duodenum and the ileum and is considered to start at the suspensory muscle of the duodenum, a location called the duodenojejunal flexure. The division between the jejunum and ileum is not anatomically distinct.
Appendix (anatomy)The appendix (: appendices or appendixes; also vermiform appendix; cecal [or caecal] appendix; vermix; or vermiform process) is a finger-like, blind-ended tube connected to the cecum, from which it develops in the embryo. The cecum is a pouch-like structure of the large intestine, located at the junction of the small and the large intestines. The term "vermiform" comes from Latin and means "worm-shaped". The appendix was once considered a vestigial organ, but this view has changed since the early 2000s.
Large intestineThe large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being removed by defecation. The colon is the longest portion of the large intestine, and the terms are often used interchangeably but most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal.
Thoracic diaphragmThe thoracic diaphragm, or simply the diaphragm (ˈdaɪəfɹæm; diáphragma), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important muscle of respiration, and separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity: as the diaphragm contracts, the volume of the thoracic cavity increases, creating a negative pressure there, which draws air into the lungs.
EsophagusThe esophagus (American English) or oesophagus (British English, see spelling differences; both iːˈsɒfəɡəs,_ɪ-; : esophagi, esophaguses, oesophagi or oesophaguses), colloquially known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach.
Small intestineThe small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in diameter.
HindgutThe hindgut (or epigaster) 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. Arterial supply is by the inferior mesenteric artery, and venous drainage is to the portal venous system. Lymphatic drainage is to the chyle cistern. The hindgut is innervated via the inferior mesenteric plexus.
Ileocecal valveThe ileocecal valve (ileal papilla, ileocaecal valve, Tulp's valve, Tulpius valve, Bauhin's valve, ileocecal eminence, valve of Varolius or colic valve) is a sphincter muscle valve that separates the small intestine and the large intestine. Its critical function is to limit the reflux of colonic contents into the ileum. Approximately two liters of fluid enters the colon daily through the ileocecal valve. The histology of the ileocecal valve shows an abrupt change from a villous mucosa pattern of the ileum to a more colonic mucosa.
AbdomenThe abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax. In humans, the abdomen stretches from the thorax at the thoracic diaphragm to the pelvis at the pelvic brim.
Connective tissueConnective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells.
Simple columnar epitheliumSimple columnar epithelium is a single layer of columnar epithelial cells which are tall and slender with oval-shaped nuclei located in the basal region, attached to the basement membrane. In humans, simple columnar epithelium lines most organs of the digestive tract including the stomach, and intestines. Simple columnar epithelium also lines the uterus. Cilia and Mucociliary clearance Simple columnar epithelium is further divided into two categories: ciliated and non-ciliated (glandular).
