No abstract available. Original Title. Anatomia laringe e hipofaringe. Avaliacao por TC e RM. Primary Subject. RADIOLOGY AND NUCLEAR MEDICINE (C) . Anatomía de la garganta El cáncer hipofaríngeo (cáncer laringofaríngeo) se origina en la hipofaringe (laringofaringe), que es la parte inferior. É fundamental que o radiologista conheça a anatomia pertinente a esta região e . O abaulamento do contorno da orofaringe e hipofaringe, em conjunto com o.
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Los botones se anatoima debajo. The epithelial lining of the GI hipofarinve is larger than a tennis court. These epithelial cells have a rapid turnover, with a lifespan of 3 to 7 days, and have considerable interaction with endogenous and exogenous materials.
The enteric nervous system Chapterwhich is composed of a complex array of neurons and ganglia organized around the myenteric Auerbach and submucosal Meissner plexus located within the wall of the esophagus, stomach, and intestinal tract, contains between 10 and million neurons—equal to the total number in the spinal cord.
Although it is an independent nervous system, complex interactions with the autonomic and central nervous systems are necessary for normal function.
Recent evidence suggests abnormal interactions among the enteric, autonomic, and central nervous systems in the development and continuation of symptoms in functional bowel disorders such as irritable bowel syndrome Chapter The immunologic system of the GI tract is the largest immune organ in the body Chapter It consists of luminal and epithelial barrier defenses, cellular components such as T and B cells, and noncellular inflammatory mediators.
The GI immune system plays a role in systemic autoimmune disorders and immune tolerance. The GI endocrine system is stimulated by the ingestion of food. Secretion of hormones from endocrine cells responds to nutrients and to stimulation from the central nervous system. The motility of the GI tract depends on a complex interaction between smooth muscle and the enteric nervous system.
The interstitial cells of Cajal act as pacemakers of the GI tract and are responsible for the smooth, orderly transport of material from the mouth to the anus Chapter With aging, the GI tract undergoes numerous changes.
Epithelial cells interact with the environment and, given the appropriate genetic background, may undergo neoplastic transformation. Colon cancer Chapter is the second most common malignancy in the United States, and the GI tract collectively has more cancers than any other organ in the body. El agua permite que los alimentos se disuelvan y se perciba su sabor en el sentido del gusto.
Activan la amilasa salival o ptialina. Es una sustancia antimicrobiana que destruye las bacterias contenidas en los alimentos, protegiendo en parte los dientes de las caries y de las infecciones. Que le da el “sabor” a la saliva y ayuda a digerir el alimento. In between is a mixture of both types. The UES is contracted at rest and thereby creates a high pressure that prevents inspired air from entering the esophagus.
Below the UES, the esophageal wall comprises inner circular and outer longitudinal layers of muscle see Fig. The esophageal body lies within the posterior mediastinum behind the trachea and left mainstem bronchus and swings leftward to pass behind the heart and in front of the aorta. Within the diaphragmatic hiatus the esophageal body ends in a 2- to 4-cm length of asymmetrically thickened circular smooth muscle known as the lower esophageal sphincter LES see Fig.
This positioning is beneficial because it enables diaphragmatic contractions to assist the LES in maintenance of a high-pressure zone during exercise. The LES is contracted at rest, creating a high-pressure zone that prevents gastric contents from entering the esophagus. During swallowing, the LES relaxes to permit the swallowed bolus to be pushed by peristalsis from the esophagus into the stomach.
It functions primarily as a res-ervoir to store large quantities of recently ingested food, thus allowing intermittent feedings, initiating the digestive process, and releasing its contents in a controlled fashion downstream to accommodate the much smaller capacity of the duodenum. The stomach volume ranges from about 30 mL in a neonate to 1. The stomach is divided into four regions, which can be defined by anatomic or histologic landmarks Fig.
This region of the stomach has been the recent focus of intense investigation.
Controversy exists as to the nature, location, extent, and even existence of cardiac mucosa. The fundus projects upward, above the cardia and gastroesophageal junction. This dome-shaped area of the stomach is its most superior portion and is in contact above with the left hemidiaphragm and to the left with the spleen. The body, or corpus, the largest portion of the stomach, is located immediately below and continuous with the fundus.
The incisura angularis, a fixed, sharp indentation two thirds of the distance down the lesser curvature, anstomia the caudal aspect of the gastric body Fig. The gastric antrum extends from its indistinct border with the body to the junction of the pylorus with the duodenum.
These gross anatomic landmarks correspond roughly with the mucosal histology because antral mucosa pyloric gland mucosa actually extends from an area on the lesser curvature somewhat above the incisura.
The pylorus pyloric channel is a tubular structure joining the duodenum to the stomach and contains the palpable circular muscle, the pyloric sphincter. The pylorus is somewhat mobile owing to its enclosure between the peritoneum of the greater and lesser omenta but is generally located 2 cm to the right of midline at L1.
Corresponding motor and secretory functions of these regions of the stomach are discussed in detail in Chapters 46 and Four layers make up the gastric wall: Mucosa lines the gastric lumen, appearing as a smooth, velvety, blood-filled lining. The mucosa of the cardia, antrum, and pylorus is somewhat paler than that of the fundus and body. It is within the gastric mucosa that most of the functional secretory elements of the stomach are located see Chapter The submucosa, immediately deep to the mucosa, provides the dense connective tissue skeleton of collagen and elastin fibers.
Lymphocytes, plasma cells, arterioles, venules, lymphatics, and the submucosal plexus are also contained within the submucosa. The third tissue layer, the muscularis propria, is a combination of three muscle layers: The inner oblique muscle fibers course over the gastric fundus, covering the anterior and posterior aspects of the stomach wall.
The middle circular fibers encircle the body of the stomach, thickening distally to become the pyloric sphincter. The outer longitudinal muscle fibers course primarily along the greater and lesser curvatures of the stomach.
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The final layer of the stomach is the transparent serosa, a continuation of the hipofarimge peritoneum. The gastric glands of different anatomic regions of hippofaringe stomach are lined with different types of hipofairnge epithelial cells, allowing for differentiation of these regions by type of gastric gland see Fig. The first region, the cardia, is a small transition zone from esophageal squamous epithelium to gastric columnar epithelium. The cardia has been a controversial histologic area of discussion with theories suggesting that its presence is pathologic.
However, recent observations concluded that cardiac mucosa develops during gestation and is present at birth. There is a gradual transition from cardiac glands to the second region, the acid-secreting segment of the stomach. This region encompasses the gastric fundus and body and contains the parietal or oxyntic or fundic glands.
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Parietal, chief also known as pepticendocrine, mucous neck, and undifferentiated cells compose the oxyntic glands. The final region, corresponding to the antrum and pylorus, contains the pyloric glands, composed of endocrine cells, including gastrin-producing G cells and mucous cells.
By far the most numerous and distinctive gastric glands are the oxyntic glands Figresponsible for the secretion of acid, intrinsic factor, and most gastric enzymes.
These fairly straight and simple tubular glands are closely associated in the areas of gastric fundus and body. A typical gland is subdivided into three areas: Endocrine cells, somatostatin-containing D cells, and histamine-secreting enterochromaffin-like ECL cells are scattered throughout the oxyntic epithelium.
Mucous neck cells differ from their surface counterparts in their synthesis of acidic, sulfated mucus rather than the neutral mucus. Hpofaringe, mucous neck cells have basal nuclei and larger mucous granules around the nucleus rather than apically located granules. Function of the two cell types appears different in that surface mucous cells are cytoprotective, whereas the mucous neck cell functions as a stem cell precursor for surface mucous, parietal, chief, and endocrine cells.
Chief cells, also known as zymogen cells, predominate in deeper layers of the oxyntic glands. Hopofaringe pyramid-shaped cells play a role in synthesis and secretion of pepsinogens I and II.
Meaning of “hipofaringe” in the Portuguese dictionary
The cytoplasm of chief cells has prominent basophilic staining owing to abundance of hipofarinhe these ribosomes are either free in cytoplasm or in association with an extensive endoplasmic reticulum system. Zymogen granules lie in the apical cytoplasm; their contents are released into the gastric lumen following fusion of the limiting membrane of the granule with the luminal membrane.
Anattomia in the lumen, pepsinogens are converted to pepsin. A variety of endocrine, or enteroendocrine, cells are scattered among the cells of the oxyntic glands. These cells vary in location, being either open or closed relative to the gastric lumen. Open endocrine cells have apical membranes containing receptors; these open cells discharge their contents by hipofqringe exocytosis into the bloodstream, thus exerting an endocrine effect. The closed endocrine cells contain several processes that anztomia near its target cells, constituting the so-called paracrine effect.
The oxyntic gland model of the closed cell is the D cell, which secretes somatostatin via long processes reaching ECL, parietal, and chief cells. The final region of the stomach encompasses the antrum and pylorus and contains extensively coiled antral glands composed of endocrine and epithelial cells. The epithelial cells are predominantly mucous cells, and there are small numbers of pepsinogen II-secreting oxyntic cells. Although also small in number, gastrin-secreting G cells play a vital physiologic role and are the prototype of the open enteroendocrine cell.
These cells, which occur hopofaringe singly or in small clusters in the mid to deep sections of antral glands Fig.
Gastrin release is stimulated by gastric distention, vagal stimulation, dietary amino acids, and peptide, with rapid appearance of the hormone into the bloodstream in the postprandial period see Chapter The apical or luminal surface of the G cell is narrowed into small microvilli thought to contain receptors responsible for amino acid and peptide stimulation of gastrin release. Significant quantities of gastrin are also secreted into the gastric lumen; gastrin is a known gastric growth and differentiation factor, mediated through upregulation of heparin-binding epidermal-like growth factor HB-EGF in gastric parietal cells.
The lower margin of the liver descends below the costal margin during inspiration. The median liver weight is g in men and g in women. The superior, anterior, and right lateral surfaces of the liver are smooth and convex, fitting against the diaphragm. The posterior surface has indentations from the colon, right kidney, and duodenum on the right lobe and the stomach on the left lobe. The portal vein receives almost all of the blood flow from the digestive tract between the proximal stomach and upper rectum as well as from the spleen, pancreas, and gallbladder Fig.
The splenic and superior mesenteric veins join behind the pancreas to form the portal vein. The splenic vein sits in a groove of the pancreas and receives the short gastric veins, pancreatic veins, left gastroepiploic vein, and inferior mesenteric vein. The portal vein receives the superior pancreaticoduodenal vein and the left gastric coronary vein. The superior mesenteric vein receives the inferior pancreaticoduodenal vein and the right gastroepiploic vein.
There is some variation in the veins that drain into the portal system. Hepatocytes are polarized epithelial cells. By analogy with glandular epithelia, the sinusoidal, canalicular, and contiguous plasma membrane domains are also called the basolateral, apical, and lateral surfaces, respectively.
The space between the endothelia and the sinusoidal villi is termed the space of Disse. There is a bidirectional exchange of liquids and solutes between the plasma and hepatocytes at the sinusoidal surface.