Rectal Venous Plexus
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Rectal Venous Plexus
The rectal venous plexus (or hemorrhoidal plexus) surrounds the rectum, and communicates in front with the vesical venous plexus in the male, and the vaginal venous plexus in the female. A free communication between the portal and systemic venous systems is established through the rectal venous plexus. This allows administration of some medications normally given by mouth to be given rectally, while still bypassing first pass metabolism. Examples include rectal Diazepam and orally dissolving medications. Parts It consists of two parts, an internal in the submucosa, and an external outside the muscular coat. Internal plexus The internal plexus presents a series of dilated pouches which are arranged in a circle around the tube, immediately above the anal orifice, and are connected by transverse branches. This internal plexus is also known in some medical communities as the Irving plexus. External plexus * The upper part of the external plexus is drained by the superior rectal vein ...
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Rectum
The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the level of the third sacral vertebra or the sacral promontory depending upon what definition is used. Its diameter is similar to that of the sigmoid colon at its commencement, but it is dilated near its termination, forming the rectal ampulla. It terminates at the level of the anorectal ring (the level of the puborectalis sling) or the dentate line, again depending upon which definition is used. In humans, the rectum is followed by the anal canal which is about long, before the gastrointestinal tract terminates at the anal verge. The word rectum comes from the Latin ''Wikt:rectum, rectum Wikt:intestinum, intestinum'', meaning ''straight intestine''. Structure The rectum is a part of the lower gastrointestinal tract ...
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Inferior Mesenteric Vein
In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV). Structure The inferior mesenteric vein merges with the splenic vein, posterior to the middle of the body of the pancreas. The splenic vein then merges with the superior mesenteric vein to form the portal vein. Tributaries Tributaries of the inferior mesenteric vein drain the large intestine, sigmoid colon and rectum. These include: * left colic vein * sigmoid veins * superior rectal vein * rectosigmoid veins Variation Anatomical variations include the inferior mesenteric vein draining into the confluence of the superior mesenteric vein ''and'' splenic vein and the inferior mesenteric vein draining in the superior mesenteric vein. Clinical significance The inferior mesenteric vein may be damaged during surgery on the body and ...
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Blood-pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" refers to the pressure in the large arteries. Blood pressure is usually expressed in terms of the systolic pressure (maximum pressure during one heartbeat) over diastolic pressure (minimum pressure between two heartbeats) in the cardiac cycle. It is measured in millimeters of mercury (mmHg) above the surrounding atmospheric pressure. Blood pressure is one of the vital signs—together with respiratory rate, heart rate, oxygen saturation, and body temperature—that healthcare professionals use in evaluating a patient's health. Normal resting blood pressure, in an adult is approximately systolic over diastolic, denoted as "120/80 mmHg". Globally, the average blood pressure, age standardized, has remained about the same since 1975 ...
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Internal Pudendal Vein
The internal pudendal veins (internal pudic veins) are a set of veins in the pelvis. They are the venae comitantes of the internal pudendal artery. Internal pudendal veins are enclosed by pudendal canal, with internal pudendal artery and pudendal nerve. They begin in the deep veins of the vulva and of the penis, issuing from the bulb of the vestibule and the bulb of the penis, respectively. They accompany the internal pudendal artery, and unite to form a single vessel, which ends in the internal iliac vein. They receive the veins from the urethral bulb, the perineal and inferior hemorrhoidal veins. The deep dorsal vein of the penis Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary), ... communicates with the internal pudendal veins, but ends mainly in the pudendal plexus. Reference ...
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Inferior Rectal Veins
The lower part of the external hemorrhoidal plexus is drained by the inferior rectal veins (or inferior hemorrhoidal veins) into the internal pudendal vein The internal pudendal veins (internal pudic veins) are a set of veins in the pelvis. They are the venae comitantes of the internal pudendal artery. Internal pudendal veins are enclosed by pudendal canal, with internal pudendal artery and pudendal .... Pathologies involving the Inferior rectal veins may cause lower GI bleeding. Depending on the degree of inflammation, they are given a grade level ranging from 1 through 4. Additional images File:Gray405.png, The perineum. The integument and superficial layer of superficial fascia reflected. References Veins of the torso {{circulatory-stub ...
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Middle Rectal Vein
The middle rectal veins (or middle hemorrhoidal vein) take origin in the hemorrhoidal plexus and receive tributaries from the bladder, prostate, and seminal vesicle. They run lateralward on the pelvic surface of the levator ani to end in the internal iliac vein. Veins superior to the middle rectal vein in the colon and rectum drain via the portal system In the circulatory system of animals, a portal venous system occurs when a capillary bed pools into another capillary bed through veins, without first going through the heart. Both capillary beds and the blood vessels that connect them are co ... to the liver. Veins inferior, and including, the middle rectal vein drain into systemic circulation and are returned to the heart, bypassing the liver. References Veins of the torso {{circulatory-stub ...
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Portal Vein
The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approximately 75% of total liver blood flow is through the portal vein, with the remainder coming from the hepatic artery proper. The blood leaves the liver to the heart in the hepatic veins. The portal vein is not a true vein, because it conducts blood to capillary beds in the liver and not directly to the heart. It is a major component of the hepatic portal system, one of only two portal venous systems in the body – with the hypophyseal portal system being the other. The portal vein is usually formed by the confluence of the superior mesenteric, splenic veins, inferior mesenteric, left, right gastric veins and the pancreatic vein. Conditions involving the portal vein cause considerable illness and death. An important example of such a condi ...
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Superior Rectal Vein
The inferior mesenteric vein begins in the rectum as the superior rectal vein (superior hemorrhoidal vein), which has its origin in the hemorrhoidal plexus, and through this plexus communicates with the middle and inferior hemorrhoidal veins. The superior rectal vein leaves the lesser pelvis and crosses the left common iliac vessels with the superior rectal artery, and is continued upward as the inferior mesenteric vein In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV) .... References Veins of the torso Rectum {{circulatory-stub ...
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Pelvis
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The pelvic region of the trunk includes the bony pelvis, the pelvic cavity (the space enclosed by the bony pelvis), the pelvic floor, below the pelvic cavity, and the perineum, below the pelvic floor. The pelvic skeleton is formed in the area of the back, by the sacrum and the coccyx and anteriorly and to the left and right sides, by a pair of hip bones. The two hip bones connect the spine with the lower limbs. They are attached to the sacrum posteriorly, connected to each other anteriorly, and joined with the two femurs at the hip joints. The gap enclosed by the bony pelvis, called the pelvic cavity, is the section of the body underneath the abdomen and mainly consists of the reproductive organs (sex organs) and the rectum, while the pelvic f ...
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Diazepam
Diazepam, first marketed as Valium, is a medicine of the benzodiazepine family that acts as an anxiolytic. It is commonly used to treat a range of conditions, including anxiety, seizures, alcohol withdrawal syndrome, muscle spasms, insomnia, and restless legs syndrome. It may also be used to cause memory loss during certain medical procedures. It can be taken by mouth, inserted into the rectum, injected into muscle, injected into a vein or used as a nasal spray. When given into a vein, effects begin in one to five minutes and last up to an hour. By mouth, effects begin after 15 to 60 minutes. Common side-effects include sleepiness and trouble with coordination. Serious side effects are rare. They include increased risk of suicide, decreased breathing, and an increased risk of seizures if used too frequently in those with epilepsy. Occasionally, excitement or agitation may occur. Long-term use can result in tolerance, dependence, and withdrawal symptoms on dose reduction ...
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First Pass Effect
The first pass effect (also known as first-pass metabolism or presystemic metabolism) is a phenomenon of drug metabolism whereby the concentration of a drug, specifically when administered orally, is greatly reduced before it reaches the systemic circulation. It is the fraction of drug lost during the process of absorption which is generally related to the liver and gut wall. Notable drugs that experience a significant first-pass effect are buprenorphine, chlorpromazine, cimetidine, diazepam, ethanol (drinking alcohol), imipramine, insulin, lidocaine, midazolam, morphine, pethidine, propranolol, and tetrahydrocannabinol (THC). First pass metabolism may occur in the liver (for propranolol, lidocaine, clomethiazole, and NTG) or in the gut (for benzylpenicillin and insulin). After a drug is swallowed, it is absorbed by the digestive system and enters the hepatic portal system. It is carried through the portal vein into the liver before it reaches the rest of the body. The liver met ...
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