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121 Cards in this Set
- Front
- Back
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regions of the abdomen
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- 2 transverse, 2 horizontal planes = 9 regions
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abdominal quadrants
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- vertical and horizontal planes through umbilicus
- umbilicus at level of intervertebral disk between 3rd and 4th vertebrae, innervated by 10th thoracic nerve |
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4 layers of alimentary tract
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The whole alimentary tract is lined with the same four layers, surrounding a central lumen:
1. Mucosa 2. Submucosa 3. Muscularis--composed of 2 layers of smooth muscle, everywhere except for the stomach, which has three muscular layers. i. An inner, circular layer ii. An outer, longitudinal layer 4. Serous--composed of visceral peritoneum. Parts of the GI tract that are attached to the body wall or to another organ lack a serous layer. The mucosa layer is different in different parts of the GI tract. The other layers are very similar, throughout the GI tract. |
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pharyngoesophageal junction
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The esophagus is a tube that connects the pharynx to the stomach. It begins at the pharyngoesophageal junction. The pharyngoesophageal sphincter is located at the pharyngoesophageal junction, made up of fibers from the cricopharyngeus muscle.
The pharyngoesophageal junction is the narrowest place of the GI tract, except for the appendix, and foreign objects tend to get lodged there. The esophagus goes down in the posterior region of the thorax, through the superior and posterior mediastinum. About an inch of esophagus enters the abdominal region, going into the stomach. - is retroperitoneal in abdominal part but is covered with peritoneum |
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what happens if the phrenic nerve is lesioned?
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If the phrenic nerve is lesioned, the fibers of the crus cannot close around the esophagus, and the contents of the stomach may reflux
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Structures that push against the esophagus and create narrow regions
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Three structures close to the esophagus push against it, and create narrowed regions in it:
1. The arch of the aorta 2. The left bronchus 3. The left atrium of the heart Stenosis of the mitral valve will increase pressure in the LA, causing the LA to compress the esophagus. |
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Diaphragmatic herne
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The lower part of the esophagus is connected by a ligament to the diaphragm. If this ligament weakens, diaphragmatic hernia may result. Diaphragmatic hernias are more common in elderly people. Either the esophagus and top of the stomach, or just part of the stomach may protrude upwards through the diaphragm, into the thorax.
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lower esophageal sphincter
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A circle of smooth muscle fibers called the lower esophageal sphincter lies close to the region of the diaphragm. This sphincter is under neural control, and opens during swallowing and vomiting.
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external esophageal sphincter
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tightens when the diaphragm contracts during inspiration.
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which two abdominal regions does the stomach span?
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1. Left hypochondrial region
2. Top of the umbilical region |
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anatomy of the stomach
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It is roughly shaped like a J. The entrance is part of the gastroesophageal junction.
Imagine a horizontal line from the GE junction, to the left edge of the stomach: it will demarcate the division between the fundus and the body of the stomach The body of the stomach merges at the bottom with the tubular, pyloric region. An indentation called the incisura angularis can sometimes be seen at the junction between the body and the pylorus. The junction between the stomach and the small intestine is marked by the pyloric sphincter. The outside curve of the stomach is called the greater curvature. The smaller, internal curve is called the lesser curvature. |
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peritoneum
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2 layers:
- parietal peritoneum: lines internal surface of abdominopelvic wall - visceral peritoneum: lines viscera (stomach, spleen) |
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peritoneal cavity
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peritoneal cavity is a potential space of capillary thinness between the parietal and visceral layers of peritoneum --> no viscera in peritoneal cavity
- normally empty except thin layer peritoneal fluid --> allows organs to move without friction, also contains leukocytes and antibodies - completely closed in males, in females communication with exterior via uterine tubes, uterine cavity, and vagina --> potential pathway of infection |
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intraperitoneal organs
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- almost completely covered with visceral peritoneum (spleen, stomach...)
- not in peritoneal cavity |
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extraperitoneal (retroperitoneal) organs
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- partially covered with peritoneum, usually on 1 side
ex. kidney between parietal peritoneum and posterior abdominal wall --> parietal peritoneum on anterior surface (with fatty tissue) The kidneys, parts of the duodenum, and the pancreas are all retroperitoneal. |
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where are the kidneys in relation to the peritoneum?
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extraperitoneal
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mesentery
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- double layer of peritoneum reflecting away from abdominal wall to enclose part or all of viscera
- continuity of visceral and parietal peritoneum --> provides a means of neurovascular communication between organ and body wall - core of connective tissue containing blood vessels, lymphatic vessels, nerves, fat, lymph nodes - viscera with mesentery are mobile, degree of mobility depends on length of mesentery |
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greater omentum
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omentum = broad double layered sheet of peritoneum passing from stomach to other abdominal organ
greater omentum (gastrocolic ligament): - hangs from greater curvature of stomach and proximal part of duodenum, after descending folds back and attaches to anterior surface of transverse colon and mesentery |
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lesser omentum (gastrohepatic and gastroduodenal ligaments)
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- connects lesser curvature of stomach and proximal part of duodenum to the liver
- ligaments are continuous with each other - gastrohepatic ligament: membranous part of lesser omentum - hepatoduodenal ligament: thickended free edge of lesser omentum -- conducts portal triad: portal vein, hepatic artery, bile duct The right border of the lesser omentum is open (foramen of Winslow/epiploic foramen) into the lesser sac |
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greater sac
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- main part of peritoneal cavity
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peritoneal fold
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i.e lateral/medial peritoneal folds
- reflection of peritoneum raised from body wall by underlying blood vessels, ducts, obliterated fetal vessels |
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peritoneal ligament
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- double layer of peritoneum (subdivision of mesentery)
- connects and organ with another organ or an organ with the abdominal wall Ex. falciform ligament: connects liver with anterior abdominal wall gastrosplenic ligament: connects stomach to spleen |
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peritoneal recess
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- pouch or concavity lined with peritoneum, often formed by peritoneal fold
Ex. subphrenic space (recess): between liver and diaphragm (on top of liver), |
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omental bursa (lesser sac)
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smaller part of peritoneal cavity
- posterior to stomach and adjoining omentum - permits free movement of the stomach because anterior and posterior walls of omental bursa slide smoothly over one another 2 recesses: - superior recess: limited superiorly by diaphragm and posterior layer of coronary ligament of liver - inferior recess: between superior part of layers of greater omentum -- most of inferior recess sealed off from main part posterior to stomach following adhesion of layers of greater omentum - omental burs communicates with greater sac via omental foramen |
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epiploic foramen (foramen of winslow)
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- connects omental bursa with greater sac
- posterior to free edge of lesser omentum --> forming hepatoduodenal ligament boundaries of omental foramen: - anteriorly: portal vein, hepatic artery, bile duct - posteriorly: IVC, right crus of diaphragm, covered with parietal peritoneum (retroperitoneal) - superiorly: caudate lobe of liver, covered with visceral peritoneum - inferiorly: first part of duodenum, portal vein, hepatic artery, bile duct |
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transverse mesocolon
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- mesentery of transverse colon, divides abdominal cavity into:
supracolic compartment: stomach, liver, spleen infracolic compartment: small intestine, ascending and descending colon, posterior to greater omentum divided into R and L infracolic spaces by mesentery of small intestine; - communication between supracolic and infracolic compartments via paracolic gutters -- grooves between lateral aspect of ascending colon or descending colon and posterolateral abdominal wall |
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lienorenal ligament (splenorenal)
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- derived from peritoneum where wall of peritoneal cavity comes in contact with omental bursa between left kidney and spleen
- lienal vessels (splenic artery and vein) pass through 2 layers - contains tail of pancreas -- only intraperitoneal section of pancreas |
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teres ligament (round ligament)
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- on free edge of falciform ligament of liver
- divides left part of liver into medial and lateral segments - remnant of fetal left umbilical vein |
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coronary ligament
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- peritoneal reflections hold liver to inferior surface of diaphragm
anterior: reflection of peritoneum from upper margin of bare area, to under surface of diaphragm; in between 2 sides of anterior continuation = falciform ligament posterior: reflected from lower margin of bare area, continuous with right layer of lesser omentum - anterior and posterior layers converge on R and L side of liver --> R and L triangular ligament |
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bare area
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- area of liver in contact with diaphragm --> has no peritoneal covering
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secondary retroperitoneal
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- structure that developed intraperitoneally and lost mesentery becoming retroperitoneal
Ex. majority of duodenum, spleen |
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primary retroperitoneal
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- organs that develop retroperitoneal and stay retroperitoneal
- receive one covering, immobile and fixed in development Ex. kidneys |
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fundus
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- dilated superior part related to left dome of diaphragm, limited inferiorly by horizontal plane of cardial orifice
- cardial notch between esophagus and fundus - does not fill with food, collects air that gathers in stomach |
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gastric canal
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- forms temporarily when swallowing between gastric folds of lesser curvature
- saliva and small quantities of masticated food and other fluids pass along gastric canal to pyloric canal |
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3 muscular layers of stomach
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1. An inner, circular layer
2. A middle, transverse layer 3. An external, oblique layer, that lies under the submucosa layer These fibers start from the angle between the esophagus and the stomach, and go down to the bottom of the stomach. They function to lift the stomach and close the gastroesophageal junction. |
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4 layers of small intestine
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The small intestine is composed of the duodenum, jejunum, and ileum.
Its is composed of four layers: 1. Mucosa 2. Submucosa 3. Muscularis 4. Serosa |
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villi of the small intestine
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The surface of the SI is covered in circular folds, formed by the submucosa --> circular folds are covered by villi of the mucosa
- villi increase surface area for absorption |
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microvilli
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The surface of the epithelial cells that form the villi are covered by projections of their plasma membranes called microvilli.
Each villi contains a tiny artery that splits into capillaries and exits the villus as a venule. |
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villi of the small intestine
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The surface of the SI is covered in circular folds, formed by the submucosa --> circular folds are covered by villi of the mucosa
- villi increase surface area for absorption |
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microvilli
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The surface of the epithelial cells that form the villi are covered by projections of their plasma membranes called microvilli.
Each villi contains a tiny artery that splits into capillaries and exits the villus as a venule. |
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duodenal cap
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When the stomach is filled with contrast material, the first part of the duodenum will also fill, and will form a structure that looks like an upside down cap, thereby named the duodenal cap.
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4 parts of duodenum
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The duodenum is C-shaped, and is composed of 4 parts:
1. The free part, which rises upward, and looks like a continuation of the gastric canal. Short, mostly horizontal. 2. The fixed/descending part is attached to the abdominal wall, curves around head of pancreas, to the right and parallel to IVC 3. The transverse part is only a few centimeters, crosses anterior to IVC and aorta, posterior to superior mesenteric vein and artery 4. The small, ascending part, at the end of the duodenum, rising towards the connection between the duodenum and the jejunum, left side of aorta, reaches inferior border of pancreas |
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hepatopancreatic ampulla
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- top of duodenum fixed in place by pancreas and liver/gallbladder --> send ducts to duodenum
- formed by union of pancreatic duct and common bile duct - The internal surface of the ampulla forms the duodenal papilla, where the two ducts open into the duodenum |
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root of mesentery
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- mesentery, fan shaped fold of peritoneum, attaches jejunum and ileum to posterior abdominal wall
root of mesentery --> directly oblique, inferiorly and to the R - extends from duodenaljejunic junction to ileocolic junction (L-->R) Crosses: - ascending and horizontal parts of duodenum - abdominal aorta - IVC - R ureter - R psoas major - R testicular/ovarian vessels |
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differentiating between jejunum and ileum
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The jejunum contains many more blood vessels than the ileum, because more absorption takes place in it. Between the blood vessels of the jejunum, the mesentery looks translucent, because it contains little fat. The mesentery of the ileum contains a lot of fat, and does not look translucent. Fewer blood vessels are visible in the ileum, and are hidden by fat.
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surface of jejunum vs. surface of ileum
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The jejunum is lined with folds called the plicae circulares: composed of reduplications of mucous membrane → 2 layers bound together by submucosa tissue; permanent folds → not obliterated when distended
The surface of the ileum is flatter, and contains 16-20 collections of lymphoid tissue called Peyer's patches – round lymphoid follicles |
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Large Intestine
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The functions of the large intestine are formation, transport, and evacuation of feces.
It is composed of the colon, rectum, and anal canal. The outside surface of the large intestine is covered with curves called haustrations, produced by bands of longitudinal muscle, called taeniae coli. The LI contains 3 taeniae coli, which are shorter than the intestine itself, and therefore bunch up the intestine, producing the haustrations (pouches between teniae). The LI starts from the ileocecal junction. A non-functional valve, called the ileocecal valve, is present between the ileum and cecum. The cecum lies inferiorly to the ileocecal junction. |
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appendix
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The appendix is located on the posteromedial surface of the cecum. It is enclosed within a fold of peritoneum connecting it to the cecum called the mesoappendix – short triangular mesentery (ceucum has no mesentery).
The appendix is located on the posteromedial surface of the cecum. It is enclosed within a fold of peritoneum connecting it to the cecum called the mesoappendix – short triangular mesentery (ceucum has no mesentery). |
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positions of the appendix
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The appendix can be located in different positions, which will create pain in different regions if it becomes inflamed. The classic position for the appendix is the pelvic position.
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appendix
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The appendix is located on the posteromedial surface of the cecum. It is enclosed within a fold of peritoneum connecting it to the cecum called the mesoappendix – short triangular mesentery (ceucum has no mesentery).
The appendix is located on the posteromedial surface of the cecum. It is enclosed within a fold of peritoneum connecting it to the cecum called the mesoappendix – short triangular mesentery (ceucum has no mesentery). |
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positions of the appendix
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The appendix can be located in different positions, which will create pain in different regions if it becomes inflamed. The classic position for the appendix is the pelvic position.
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3 regions of the colon
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The colon can be divided into three regions:
1. Ascending 2. Transverse 3. Descending The ascending colon joins the transverse colon after the right/hepatic flexure. (right lobe of liver) The transverse colon joins the descending colon in the left/splenic flexure, which is higher than the right flexure, and fixed in place. The descending colon turns into the sigmoid colon. Unlike the other regions of the colon, the sigmoid has no mesocolon. The cecum is connected to the posterior abdominal wall by a peritoneal fold, but also does not have a mesocolon. The contents of the cecum, ascending, and transverse colon are mostly liquid. Beyond the transverse colon, the colon is filled mostly with feces. |
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Functions of the liver
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- with exception of lipids every substance absorbed by alimentary tract received by liver first
1. Exocrine secretion (bile) 2. Endocrine secretion (most plasma proteins) 3. Metabolite breakdown 4. Homeostasis, nutrition, and immune defense (major producer of lymph) 5. Regulation of glucose and lipids 6. Storage of vitamins and iron 7. Modification of amino acids |
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Liver anatomy
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The liver's blood supply comes from both an arterial and a venous system.
The liver is located within the rib cage. It's lower border extends to the ileac crest (superolateral border of pelvis). The left margin usually does not cross the midline of the abdomen. It is attached to the anterior abdominal wall and the diaphragm. |
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falciform ligament
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The sickle-shaped falciform ligament is located on the anterior surface of the liver. It divides the liver into two lobes:
1. A smaller, left lobe 2. A larger, right lobe During embryonic development, the visceral peritoneum that surrounds the stomach connects the stomach to the anterior abdominal wall by two peritoneal folds, called the ventral mesogastrium. The liver develops within the ventral mesogastrium. Part of the ventral mesogastrium remains as the falciform ligament, and connects the liver to the abdominal wall. Another part of the ventral mesogastrium develops into the lesser omentum. |
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4 lobes of liver
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The liver has four lobes:
1. Right 2. Left 3. Quadrate 4. Caudate The gall bladder and inferior vena cava (bile passages, hepatic artery, portal vein) separate between the caudate, quadrate, and right lobes. The ligamentum teres is found at the inferior border of the falciform ligament. It divides the liver into the left and quadrate lobes. The ligamentum teres continues as the ligamentum venosum, located between the left and caudate lobes. In the fetus, both these ligaments (teres and falciform)were a single vessel called the ductus venosum, that carried oxygenated blood from the mother to the fetus. |
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وجهة نظر
وجهات نظر |
point of view
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liver blood supply
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The portal vein drains blood from the alimentary (digestive) tract, into the liver. At the liver, it divides into two branches:
1. The left branch supplies the left, quadrate, and caudate lobes 2. The right branch supplies the right lobe The hepatic artery (branch of celiac trunk – first main branch of abdominal aorta) , which supplies the liver with oxygenated blood, also divides into two arteries, left and right, which supply the same lobes as the left and right branches of the portal vein. The caudate lobe has the most distinct blood supply, and several branches supply it and no other lobe. The divisions of the blood supply to different regions creates a functional division in the liver. → between segments hepatic veins drain parts of adjacent segments → hepatic veins formed by union of central veins drain into IVC inferior to diaphragm – attachment of veins to IVC helps hold liver in position |
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coronary ligament
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The coronary ligament is found on the anterior and right superior surface of the liver. The coronary ligament consists of a superior sheath, and an inferior sheath, visible on the posterior surface.
The two sheaths of the coronary ligament mark out a region called the bare area, uncovered by peritoneum. coronary ligament continues as the left triangular ligament The IVC crosses down the back of the liver, behind the coronary ligament. |
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blood flow to and from liver
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The liver receives two types of blood:
1. Arterial blood supplies the parenchyma 2. Venous blood from the abdominal organs drains into the portal vein, which passes into the liver. Two veins flow into the portal vein: 1. The splenic vein i. The inferior mesenteric vein drains into the splenic vein 2. The superior mesenteric vein Flow from the splenic and superior mesenteric veins stay separated within the portal vein. Flow from the splenic vein goes into the left, caudate, and quadrate lobes, and flow from the superior mesenteric vein goes into the right lobe. |
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ducts of the bile system
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Ducts of the bile system include:
1. Left hepatic duct 2. Right hepatic duct 3. The common hepatic duct, which the right and left hepatic ducts drain into 4. The cystic duct, which connects the hepatic duct to the gal bladder. Flow inside the cystic duct is bidirectional. 5. The bile duct follows the junction between the cystic and hepatic duct, and drains into the duodenum. |
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blood flow to and from liver
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The liver receives two types of blood:
1. Arterial blood supplies the parenchyma 2. Venous blood from the abdominal organs drains into the portal vein, which passes into the liver. Two veins flow into the portal vein: 1. The splenic vein i. The inferior mesenteric vein drains into the splenic vein 2. The superior mesenteric vein Flow from the splenic and superior mesenteric veins stay separated within the portal vein. Flow from the splenic vein goes into the left, caudate, and quadrate lobes, and flow from the superior mesenteric vein goes into the right lobe. |
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ducts of the bile system
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Ducts of the bile system include:
1. Left hepatic duct 2. Right hepatic duct 3. The common hepatic duct, which the right and left hepatic ducts drain into 4. The cystic duct, which connects the hepatic duct to the gal bladder. Flow inside the cystic duct is bidirectional. 5. The bile duct follows the junction between the cystic and hepatic duct, and drains into the duodenum. There is a circle of smooth muscle surrounding the distal end of the bile duct. There is no smooth muscle anywhere else on the biliary ducts. The gal bladder has three layers of muscle: circular, longitudinal, and oblique. The distal end of the gall bladder is called the fundus. |
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what can you find in the free border of the lesser omentum?
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The bile duct, between the common hepatic and cystic ducts can be found most easily in the free right border of the lesser omentum.
The portal vein and hepatic artery also pass within the free right border of the lesser omentum. Within the folds of the omentum- -the bile duct is on the right -the portal vein is left and posterior to the artery -the artery is anterior (duct is dextra, portal vein is posterior, artery is anterior) |
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sphincter of oddi
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The place where the bile duct enters the duodenum is called the sphincter of Oddi.
Inside the sphincter of Oddi are two ducts: 1. The main pancreatic duct 2. The bile duct The distal end of the bile duct is surrounded by a circle of muscle that is not part of the sphincter of Oddi. The sphincter of Oddi encloses both ducts. It closes the opening to the duodenum, to prevent reflux into the bile system. |
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pancreas
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The pancreas is located between the parietal peritoneum and the posterior abdominal wall. Its head is surrounded by duodenum, and its tail is covered with peritoneum.
The two main functions of the pancreas are: 1. Exocrine secretion of pancreatic enzymes by the pancreatic acini 2. Endocrine secretion of insulin and glucagon by the islets of Langerhans The head of the pancreas has a little bump called the uncinate process. |
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sphincter of oddi
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The place where the bile duct enters the duodenum is called the sphincter of Oddi.
Inside the sphincter of Oddi are two ducts: 1. The main pancreatic duct 2. The bile duct The distal end of the bile duct is surrounded by a circle of muscle that is not part of the sphincter of Oddi. The sphincter of Oddi encloses both ducts. It closes the opening to the duodenum, to prevent reflux into the bile system. |
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pancreas
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The pancreas is located between the parietal peritoneum and the posterior abdominal wall. Its head is surrounded by duodenum, and its tail is covered with peritoneum.
The two main functions of the pancreas are: 1. Exocrine secretion of pancreatic enzymes by the pancreatic acini 2. Endocrine secretion of insulin and glucagon by the islets of Langerhans The head of the pancreas has a little bump called the uncinate process. |
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transverse mesocolon of the pancreas
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Layers of the transverse mesocolon are attached to the posterior surface of the pancreas and connect it to the posterior abdominal wall. The inferior layer of the transverse mesocolon folds up under the pancreas and covers its inferior surface. The superior layer covers the superior surface of the pancreas.
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arteries and veins in relation to pancreas
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(picture only shows arteries)
The IVC and aorta pass just behind the head of the pancreas. The superior mesenteric vein enters the pancreas and divides the head from the body. It is found with the portal vein, behind the neck of the pancreas. Behind the pancreas can be found the left suprarenal gland, left kidney, and renal vessels. The splenic vein and artery are found behind the tail of the pancreas. |
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spleen
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The functions of the spleen are
1. Removal of old erythrocytes from the circulation 2. Provision of WBCs and antibodies The spleen is a very fleshy organ, with several surfaces. Organs close to the spleen include: 1. The stomach, lying over the gastric surface of the spleen 2. The left flexure/splenic flexure of the colon 3. The left kidney The spleen is located parallel to, and just behind the tenth rib. Ribs 9-11 pass over its surface. |
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gastrolienal ligament
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- attaches stomach to spleen
- composed of 2 layers peritoneum |
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fascia of posterior abdominal wall
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The posterior abdominal wall is covered by a layer of fascia continuous with the fascia transversalis of the anterior wall, lying between the muscles and parietal peritoneum.
The thoracolumbar fascia is a multilayered complex of fascia that covers many of the back muscles. |
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back muscles
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The latissiumus dorsi covers most of the back.
The external obliques are visible from the back. The serratus posterior is another back muscle. |
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muscles that hold the spine erect
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Three muscles called the erector spinae muscles help hold the spine in the erect position:
1. Iliocostalis 2. Longissimus 3. Spinalis |
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deep muscles of the back -- help keep spine straight
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1. Multifidus
2. Rotatorus spinae 3. Intertransversus 4. Quadratus lumborum -originates from the ribs, goes to the iliac crest. Helps with side to side flexion of the spine. The kidneys sit on top of the quadratus lumborum. |
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posterior abdominal wall muscles
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The quadratus lumborum originates from the bottom of the twelfth rib and the lumbar vertebrae, and inserts on the iliolumbar ligament and iliac crest.
The psoas major originates from the lumbar vertebrae and passes downwards, to the femur, going under the inguinal ligament. The iliacus, sitting on the internal aspect of the pelvis, merges with the psoas major, to insert on the lesser trochanter of the femur. Sometimes, a psoas minor runs parallel with the major. The vertebral column also composes part of the posterior abdominal wall. |
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abdominal aorta
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The aorta descends down the abdomen, sitting on top of the vertebral column.
The vessels branching off the abdominal aorta can be categorized as anterior, lateral, or circumflex: 1. Anterior i. Celiac trunk--supplies the liver, spleen, and part of the pancreas and duodenum ii. Superior mesenteric artery--supplies the small intestine and the right side of the large intestine iii. Inferior mesenteric artery--supplies left side of large intestine 2. Lateral i. Renal arteries--supply the kidneys. About a liter of blood goes to the kidneys every minute. ii. Suprarenal arteries--supply the suprarenal glands iii. Gonadal arteries--supply the testes or ovaries 3. Circumflex i. Inferior phrenic--is the first branches off the abdominal aorta, and supplies the inferior surface of the diaphragm and the suprarenal glands ii. Lumbar arteries--supply muscles of abdominal wall The aorta bifurcates and ends around the level of L4. |
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venous drainage of the abdomen
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The IVC is located to the right of the aorta. Pressure on the IVC is common (ex: in pregnancy) and causes accumulation of blood and vein dilation in the lower region of the body.
Like the aorta, the IVC splits into the common iliac veins at the L4 level. |
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lymphatic drainage -- abdomen
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Lymphatic drainage of all the abdominal organs goes into internal lymph nodes, mainly clustered around the aorta. In general, the abdominal lymph nodes are organized around the major blood vessels. The biggest lymph vessel is the cisterna chyli. The thoracic duct flows out of the cisternal chyli, and drains into the left subclavian.
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lumbar plexus
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"Interested In Getting Laid On Friday"
Iliohypogastric [L1] Ilioinguinal [L1] Genitofemoral [L1, L2] Lateral femoral cutaneous [L2, L3] Obtruator [L2, L3, L4] Femoral [L2, L3, L4] 2 nerves from 1 root: Ilioinguinal (L1), Iliohypogastric (L1). 2 nerves from 2 roots: Genitofemoral (L1,L2), Lateral Femoral (L2,L3). 2 nerves from 3 roots: Obturator (L2,L3,L4), Femoral (L2,L3,L4). |
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Iliohypogastric
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L1 Supply abdominal muscles and skin of pubic and inguinal regions
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Ilioinguinal
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L1 Supply abdominal muscles and skin of pubic and inguinal regions
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genitofemoral
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L1-2 Pierces the psoas major and splits into the genital and femoral branches. The genital branch enters the inguinal canal and innervates the cremaster.
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Femoral
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L2-4 A very big nerve. Innervates the anterior compartment of the leg.
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Lateral cutaneous nerve of the thigh
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L2-3 Supplies skin of anterolateral surface of thigh.
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internal hemorrhoids
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The portal system drains the intestines and carries venous blood directly to the liver. The splenic, superior mesenteric, and inferior mesenteric veins drain into the hepatic portal vein.
The inferior mesenteric drains the superior part of the rectum. The pancreas wraps around the inferior mesenteric, and pancreatic tumors can compress the inferior mesenteric and lead to internal hemorrhoids. |
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kidney in posterior abdominal wall
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The kidneys are the most prominent organs in the posterior abdominal wall.
The right kidney is slightly lower than the left, because the liver presses down on it from above. The kidneys are protected by the rib cage. The right kidney is next to the duodenum. The left is next to the pancreas |
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anatomy of kidney
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The kidney is composed of the
1. Renal cortex 2. Renal medulla. Structures called pyramids sit inside the medulla. The apex of each pyramid points towards the center of the kidney. The apex of a pyramid is called the papilla. A structure called the minor calyx touches each papilla. The minor calyx turns into the major calyx, which is the collecting site for the urine. The major calyx flows into the ureter. The hilum of the kidney contains the ureter, renal artery, and renal vein. |
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nephron
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The function of the kidney is to secrete wastes and maintain proper blood volume. The functional unit of the kidney is the nephron.
The nephron is composed of: 1. Bowman's capsules i. Each capsule contains a collection of blood vessels called a glomerulus, with an afferent arteriole going into it, and an efferent going out 2. Proximal convoluted tubule 3. Loop of Henle 4. Distal convoluted tubule |
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blood supply/drainage of the kidneys
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The kidneys are supplied by the renal arteries and drained by the renal veins. The veins are anterior to the artery.
The left kidney has a longer vein, because the IVC is on the right of the body, farther away from the left kidney. The superior mesenteric artery sits on top of the left renal vein. The renal artery branches out just before it enters the kidney, to supply the whole kidney with blood. |
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suprarenal blood supply
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Two endocrine glands, called the suprarenal glands, sit on top of each kidney. Three different vessels supply the suprarenal glands:
1. The inferior suprarenal branch of the renal artery 2. The middle suprarenal branch of the aorta 3. The superior suprarenal branch of the inferior phrenic Venous drainage: 1. The right suprarenal gland drains straight into IVC 2. The left suprarenal gland drains into left renal vein |
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innervation of the kidneys
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The kidneys have sympathetic innervation from the sympathetic trunk and parasympathetic mainly from the right vagus.
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Abdominal innervation
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Innervation of the abdomen is almost entirely autonomic.
Splanchnic nerves carrying presynaptic, sympathetic fibers, and branches of the vagus nerve, carrying parasympathetic fibers innervate the abdominal viscera. Contributors to the autonomic innervation of the abdomen are the: 1. Anterior vagal trunk 2. Posterior vagal trunk 3. Sympathetic trunk, from T1 to L2 4. Splanchnic nerves that come off the sympathetic trunk The pelvic region is innervated mostly by a series of splanchnic nerves. All the ganglia and nerve plexi are a mixture of sympathetic and parasympathetic innervation. Typically, nerves travel along the blood vessels on their way to their target organs, innervating the vessels themselves as they proceed. |
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ganglia of the celiac trunk
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On each side of the celiac trunk is a celiac ganglion.
The superior mesenteric ganglion is next to the superior mesenteric artery. The aorticorenal ganglia sit on the renal artery. The aortic plexus is located within the fascia that surrounds the aorta. The inferior mesenteric ganglion is next to the inferior mesenteric artery. The lower abdominal region is innervated by the superior hypogastric plexus. (below bifurcation of aorta) |
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innervation of stomach and duodenum
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The anterior and superior vagal trunks (continuations of the left and right vagus nerves, respectively) descend along the esophagus and innervate the stomach and duodenum. Nerves follow closely along blood vessels, and synapse on the target organs. Vagus nerve = parasympathetic
The greater splanchnic nerve gives off fibers that synapse in the celiac ganglion, and proceed to the stomach, duodenum, and liver, to provide sympathetic innervation. |
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pancreas innervation
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The pancreas is mostly innervated by the posterior vagal trunk (parasympathetic), which gives off fibers that synapse on the pancreas. Splanchnic nerves (sympathetic) synapse on the celiac ganglia, and send sympathetic fibers to the pancreas.
The pancreas, like most abdominal organs, has very little innervation for pain. The membranes enclosing the organs (peritoneum, periosteum, etc) are well innervated for pain. Therefore, inflammation of an organ can be felt only when it presses against its surrounding sheath. The minimal pain innervation of the abdominal organs explains why cancer of these organs is rarely diagnosed in its early stages. |
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liver and biliary innervation
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The anterior and posterior vagal trunks (parasympathetic) descend down the aorta and send fibers to the hepatic nerve plexus. The hepatic plexus follows the hepatic artery and portal vein to the liver, carrying parasympathetic fibers from the vagus and sympathetic fibers from the celiac plexus, originated from the greater splanchnic nerve.
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innervation of the intestines
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The innervation of the small intestine come from the superior mesenteric ganglion, and the large intestine is partly innervated by the inferior mesenteric ganglion.
****Parasympathetic innervation of the lower abdomen comes from parasympathetic splanchnic nerves derived from the pelvic splanchnic nerves, originating from the spinal cord, rather than from the vagus. *****Sympathetic innervation comes from the superior hypogastric plexus. (below bifurcation of aorta) The rectum is innervated by the pudendal nerve, which provides somatic afferent innervation (because the rectum is under conscious control). Different spinal cord segments innervate different regions of the intestines. |
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Intestinal Neuronal Dysplasia
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Intestinal neuronal dysplasia occurs when nerve synapses on the organs do not develop properly, leading to a lack of parasympathetic innervation. Individuals have impaired peristalsis. Babies with this condition can't digest food properly.
If the impaired area is large enough, surgeons may need to do a multivisceral transplant--removal of the GI tract, and transplantation of new organs. |
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innervation of kidneys
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Innervation of the kidneys comes from the aorticorenal ganglia. Sympathetic fibers come from the least and lesser splanchnic nerves. Parasympathetic innervation comes from both the vagus and the pelvic splanchnic nerves, which send fibers that synapse on the target organs, as usual.
The suprarenal glands are innervated by fibers from the celiac ganglion (sympathetic). |
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Referred pain
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stomach -- epigastric and left hypochondriacal
duodenum -- epigastric and R shoulder pancreatic head -- inferior epigastric region small intestine -- periumbilical region colon -- hypogastric (suprapubic), lower left quadrant appendix -- Periumbilical region and lower right quadrant (but variable, depending on placement of the appendix Gall bladder and liver -- Epigastric and right hypochondriac regions. May cause pain on posterior thoracic wall or right shoulder, if diaphragm is irritated Kidneys and ureters -- Small of back, flank (between last rib and hip), extending to inguinal region and genitals |
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abdominal aorta
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Beyond the diaphragm, the thoracic aora becomes the abdominal aorta. It passes the diaphragm behind the superior fibers, through the aortic hiatus, at the level of **T12.**
At the level of **L4**, the aorta bifurcates into the two common iliac arteries. |
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inferior phrenic arteries
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The inferior phrenic arteries supply the diaphragm, together with other branches that came from the thoracic aorta (musculophrenic and pericardiophrenic).
The superior suprarenal arteries branch off the inferior phrenic arteries, and help supply the adrenal glands. |
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lumbar arteries
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The lumbar arteries branch off the sides of the aorta and supply the posterior abdominal wall. There are 4 lumbar arteries on each side.
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median sacral artery
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The median sacral artery branches off the aorta at the level of the bifurcation, and continues down the sacrum to supply the wall of the pelvis, down to the body of the coccyx.
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middle suprarenal arteries
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The middle suprarenal arteries are small branches of the abdominal aorta, close to the inferior phrenics. They supply the adrenal glands.
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renal arteries
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The renal arteries branch off the aorta below the suprarenal arteries. The left renal is slightly higher than the right, because the right kidney is pressed downwards by the liver.
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gonadal arteries
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The gonadal arteries branch off the middle of the abdominal aorta and descend to the ovaries or testes(which develop higher up in the abdominal cavity during embryonic life--hence, the high branching of the gonadal arteries).
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Branching levels of the unpaired visceral arteries
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T12 - celiac
Superior mesenteric - L1 Inferior mesenteric - L3 |
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Blood supply to 3 regions of GI tract
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The GI tract can be divided into 3 regions, each of which is supplied by one of the unpaired visceral branches:
1. The foregut extends from the mouth to the middle of duodenum. It is supplied by branches of the celiac trunk. 2. The midgut extends from the middle of duodenum to the border between the proximal 2/3 of transverse colon and the distal 1/3. It is supplied by branches of the superior mesenteric. 3. The hindgut extends from the distal 1/3 of transverse colon to the rectum. It is supplied by branches of the inferior mesenteric. |
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branches of the celiac trunk
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Three arteries branch off the celiac trunk:
1. Splenic--the biggest branch of the celiac trunk i. The left gastroepiploic branches off the splenic, and follows the greater curvature of the stomach 2. Left gastric--follows the lesser curvature of the stomach. Supplies the stomach and part of the esophagus. 3. Common hepatic--divides into 3 branches: i. The right gastric follows the lesser curvature of the stomach and anastamoses with the left gastric ii. The gastroduodenal gives off one branch 1. The right gastroepiploic branches off the gastroduodenal and extends along the right side of the greater curvature of the stomach 2. The gastroduodenal continues as the superior pancreaticoduodenal artery, which supplies the duodenum The inferior pancreaticoduodenal branches off the superior mesenteric branch of the aorta, and joins the superior pancreaticoduodenal artery. The duodenum can be divided into two regions, distal and proximal to where the bile duct and main pancreatic duct enter the duodenum through the sphincter of Oddi. Above this division, the celiac trunk supplies the duodenum. Below it, the superior mesenteric supplies the duodenum. 3. The proper hepatic supplies the liver If the proper hepatic is occluded, the liver suffers ischemia. If the common hepatic is occluded, the blood will flow through the left gastric artery, and still reach the liver. |
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Branches of the Superior Mesenteric Artery
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The midgut extends from the middle of the duodenum to the proximal 2/3 of the transverse colon, and is supplied by branches of the superior mesenteric artery:
1. Jejunal branches, on the upper left 2. Ileal branches, on the lower left 3. Ileocolic branch (usually there's just one), on the right 4. Right colic artery 5. Middle colic artery |
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Branches of the Superior Mesenteric Artery
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The midgut extends from the middle of the duodenum to the proximal 2/3 of the transverse colon, and is supplied by branches of the superior mesenteric artery:
1. Jejunal branches, on the upper left 2. Ileal branches, on the lower left 3. Ileocolic branch (usually there's just one), on the right 4. Right colic artery 5. Middle colic artery |
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Branches of the Inferior Mesenteric Artery
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The hindgut begins at the distal 1/3 of the transverse colon, and is supplied by the three branches of the inferior mesenteric artery.
1. Left colic artery 2. Sigmoid artery (or arteries) 3. Superior rectal artery (supplies only the inferior region of the rectum. The superior and middle regions are supplied by branches of the iliac The left colic, sigmoid, and superior rectal arteries all send branches into the marginal artery, which proceeds along the length of the colon. The marginal artery communicates with the ileac, and helps supply the legs when the common ileac is occluded. Straight branches off the marginal artery, called the vasa recta, supply the wall of the LI. |
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appendicular artery
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The appendicular artery is a branch of the ileocolic branch of the superior mesenteric artery.
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venous drainage of abdomen
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The venous system can be divided into 4 different components:
1. Caval--drains the superior region of the body (VC?) 2. Azygos--drains the walls of the body 3. Vertebral--a plexus of small veins along the vertebral column. These veins have no valves, and allow blood to circulate in both directions, depending on the position of the body 4. Portal--all abdominal organs drain into the portal vein |
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portal vein
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The splenic vein and the inferior mesenteric vein flow into the portal vein.
The portal vein splits into the two hepatic veins. The hepatic veins provide venous drainage of the liver. Portal sinusoids in the liver drain into the three hepatic veins (left, middle, and right) |
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venous drainage of the liver
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The splenic vein and the inferior mesenteric vein flow into the portal vein.
The portal vein splits into the two hepatic veins. The hepatic veins provide venous drainage of the liver. Portal sinusoids in the liver drain into the three hepatic veins (left, middle, and right) The hepatic veins drain into the IVC, in the bare area region of the liver. The superior mesenteric vein goes to the right hepatic branch of the portal vein, and supplies the right lobe of the liver. The inferior mesenteric vein goes to the left hepatic branch of the portal vein, and supplies the left, quadrate, and caudate lobe. |
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Portal Hypertension
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h branch of the portal vein is surrounded by a sheath of connective tissue. Cirrhotic livers have a more connective tissue surrounding their veins than healthy livers. This extra connective tissue obstructs venous drainage in the hepatic veins.
Because the portal system is connected to many other veins, portal hypertension can affect several organs: The gastric vein, along the lesser curvature of the stomach, drains the stomach and bottom of the esophagus, and flows into the portal vein. The upper part of the esophagus drains into the azygos, and then into the IVC. If the portal system is occluded, drainage of the esophagus will be diverted into the IVC. The rectum is drained directly into the IVC The umbilical vein drains either into the azygos system or the portal system. If the portal system is occluded, blood from the intestines, will drain into the azygos system, which drains the posterior abdominal walls, and then into the IVC. Portal hypertension will put stress on the rectum, lower esophagus, and abdominal cavity. Rupture of veins in these areas due to portal hypertension may result in: 1. Ischemia of the lower esophagus, which can be fatal 2. Hemorrhoids, due to rupture of veins draining the rectum 3. Ascites, buildup of excess fluid in the abdomen |
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lymphatic drainage of the abdomen
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All lymph in the abdomen drains into the thoracic duct.
The right lymphatic duct drains the right upper quadrant of the body. The other three quadrants are drained by the thoracic duct, including the abdomen. Lymph nodes found in the abdominal viscera can be categorized as: 1. The distal group (nodes that drain the organs). These nodes are located on the vessels that supply the organs. 2. A group along the aorta, subdivided into 3 groups: i. Pre-aortic lymph nodes, anterior to the aorta--receive lymph from vessels along celiac trunk and superior and inferior mesenteric arteries ii. Lateral group, lateral to the aorta--receive lymph from vessels along renal and suprarenal arteries iii. Retro-aortic group, behind the aorta--receive lymph from the posterior abdominal wall |
