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Oesophagus
The esophagus (American English), oesophagus (British English), or œsophagus ( archaic spelling) ( see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), colloquially known also as the food pipe, food tube, 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. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word ''esophagus'' is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω (phérō, "I carry") + ἔφαγον (éphagon, "I ate"). The wall of the esophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between lay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esophageal Veins
The esophageal veins drain blood from the esophagus to the azygos vein, in the thorax, and to the inferior thyroid vein in the neck. It also drains, although with less significance, to the hemiazygos vein, posterior intercostal vein and bronchial veins. In the abdomen, some drain to the left gastric vein which drains into the portal vein. See also * Esophageal varices Esophageal varices are extremely Vasodilation, dilated sub-mucosal veins in the lower third of the esophagus. They are most often a consequence of portal hypertension, commonly due to cirrhosis. People with esophageal varices have a strong tendenc ... References External links * * () * https://web.archive.org/web/20080506103555/http://www.med.mun.ca/anatomyts/digest/avein6.htm Thoracic veins Veins of the torso {{circulatory-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomach
The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical terms related to the stomach. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach is involved in the gastric phase, gastric phase of digestion, following the cephalic phase in which the sight and smell of food and the act of chewing are stimuli. In the stomach a chemical breakdown of food takes place by means of secreted digestive enzymes and gastric acid. It also plays a role in regulating gut microbiota, influencing digestion and overall health. The stomach is located between the esophagus and the small intestine. The pyloric sphincter controls the passage of partially digested food (chyme) from the stomach into the duodenum, the first and shortest part of the small intestine, where p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digestive Tract
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the Digestion, digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. The GI tract contains all the major organ (biology), organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digestion, digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Nephrozoa, Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores (ostium (sponges), ostia) throughout their body for digestion and a larger dorsal pore (osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Heart
The heart is a muscular organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum. In humans, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: ep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striated Muscle
Striated muscle tissue is a muscle tissue that features repeating functional units called sarcomeres. Under the microscope, sarcomeres are visible along muscle fibers, giving a striated appearance to the tissue. The two types of striated muscle are skeletal muscle and cardiac muscle. Structure Striated muscle tissue contains T-tubules which enables the release of calcium ions from the sarcoplasmic reticulum. Skeletal muscle Skeletal muscle includes skeletal muscle fibers, blood vessels, nerve fibers, and connective tissue. Skeletal muscle is wrapped in epimysium, allowing structural integrity of the muscle despite contractions. The perimysium organizes the muscle fibers, which are encased in collagen and endomysium, into fascicles. Each muscle fiber contains sarcolemma, sarcoplasm, and sarcoplasmic reticulum. The functional unit of a muscle fiber is called a sarcomere. Each muscle cell contains myofibrils composed of actin and myosin myofilaments repeated as a sarcomer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smooth Muscle
Smooth muscle is one of the three major types of vertebrate muscle tissue, the others being skeletal and cardiac muscle. It can also be found in invertebrates and is controlled by the autonomic nervous system. It is non- striated, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It can be divided into two subgroups, ''single-unit'' and ''multi-unit'' smooth muscle. Within single-unit muscle, the whole bundle or sheet of smooth muscle cells contracts as a syncytium. Smooth muscle is found in the walls of hollow organs, including the stomach, intestines, bladder and uterus. In the walls of blood vessels, and lymph vessels, (excluding blood and lymph capillaries) it is known as vascular smooth muscle. There is smooth muscle in the tracts of the respiratory, urinary, and reproductive systems. In the eyes, the ciliary muscles, iris dilator muscle, and iris sphincter muscle are types of smooth muscles. The iris dilator and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Columnar Epithelia
Simple 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. Structure Simple columnar epithelium is further divided into two categories: ciliated and non-ciliated (glandular). The ciliated part of the simple columnar epithelium has tiny hairs which help move mucus and other substances up the respiratory tract. The shape of the simple columnar epithelium cells are tall and narrow giving a column like appearance. the apical surfaces of the tissue face the lumen of organs while the basal side faces the basement membrane. The nuclei are located closer along the basal side of the cell. Absorptive columnar epithelium is characterized as having a striated border on its apical side, this bord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratified Squamous Epithelium
A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basal membrane. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural integrity. Although this epithelium is referred to as squamous, many cells within the layers may not be flattened; this is due to the convention of naming epithelia according to the cell type at the surface. In the deeper layers, the cells may be columnar or cuboidal. There are no intercellular spaces. This type of epithelium is well suited to areas in the body subject to constant abrasion, as the thickest layers can be sequentially sloughed off and replaced before the basement membrane is exposed. It forms the outermost layer of the skin and the inner lining of the mouth, esophagus and vagina. In the epidermis of skin in mammals, reptiles, and birds, the layer of keratin in the outer layer of the stratified squamous epithelial surface is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrous Tissue
Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly 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. Blood and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leukocytes. The term "connective tissue" (in German, ) was introduced in 1830 by Johannes Peter Müller. The tissue was already recognized as a distinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscular Layer
The muscular layer (muscular coat, muscular fibers, muscularis propria, muscularis externa) is a region of muscle in many organs in the vertebrate body, adjacent to the submucosa. It is responsible for gut movement such as peristalsis. The Latin, tunica muscularis, may also be used. Structure It usually has two layers of smooth muscle: * inner and "circular" * outer and "longitudinal" However, there are some exceptions to this pattern. * In the stomach, there are three layers to the muscular layer. Stomach contains an additional oblique muscle layer just interior to circular muscle layer. * In the upper esophagus, part of the externa is ''skeletal muscle'', rather than smooth muscle. * In the vas deferens of the spermatic cord, there are three layers: inner longitudinal, middle circular, and outer longitudinal. * In the ureter, the smooth muscle orientation is opposite that of the GI tract. There is an inner longitudinal and an outer circular layer. The inner layer of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submucosa
The submucosa (or tela submucosa) is a thin layer of tissue in various organs of the gastrointestinal, respiratory, and genitourinary tracts. It is the layer of dense irregular connective tissue that supports the mucosa (mucous membrane) and joins it to the muscular layer, the bulk of overlying smooth muscle (fibers running circularly within layer of longitudinal muscle). The submucosa ('' sub-'' + ''mucosa'') is to a mucous membrane what the subserosa ('' sub-'' + ''serosa'') is to a serous membrane. Structure Blood vessels, lymphatic vessels, and nerves (all supplying the mucosa) will run through here. In the intestinal wall, tiny parasympathetic ganglia are scattered around forming the submucous plexus (or "Meissner's plexus") where preganglionic parasympathetic neurons synapse with postganglionic nerve fibers that supply the muscularis mucosae. Histologically, the wall of the alimentary canal shows four distinct layers (from the lumen moving out): mucosa, submuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mucosa
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is mostly of endodermal origin and is continuous with the skin at body openings such as the eyes, eyelids, ears, inside the nose, inside the mouth, lips, the genital areas, the urethral opening and the anus. Some mucous membranes secrete mucus, a thick protective fluid. The function of the membrane is to stop pathogens and dirt from entering the body and to prevent bodily tissues from becoming dehydrated. Structure The mucosa is composed of one or more layers of epithelial cells that secrete mucus, and an underlying lamina propria of loose connective tissue. The type of cells and type of mucus secreted vary from organ to organ and each can differ along a given tract. Mucous membranes line the digestive, respiratory and rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
