Portal Vein It takes an oblique coursetowards the right shoulder at a 20 to 80 degree angle to the spine. It is a thin-walled, valve less vascular structure that courses along the pancreatic neck and bile duct, and enters the liver at the porta hepatis.
Full Answer
The anatomical position is a standing position, with the head facing forward and the arms to the side. The palms are facing forward with the fingers extended, and the thumbs are pointing away from the body. The feet are spaced slightly apart with the toes pointing forward.
Portal venous system (PVS) drains blood from the gastrointestinal tract (apart from the lower section of rectum), spleen, pancreas, and gallbladder to the liver.
From an embryological point of view, the portal venous system is formed from the 4th to the 12th gestation week, developing from the vitelline venous system in close relation with the umbilical venous system. The typical branching pattern of the main portal vein occurs in 65% of individuals in the general population.
The portal vein (PV) is the main vessel of the portal venous system (PVS), which drains the blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver. There are several variants affecting the PV, and quite a number of congenital and acquired pathologies.
When you take Anatomy and Physiology, you’ll learn about the anatomical position, as well as some basic directional terms. These terms may seem complicated at first, but they are easy to learn, and I’m going to give you some tips for remembering them.
Anatomy Directional Terms. Here’s an important tip for understanding directional terms: they are usually grouped in pairs of opposites. If you can learn the meaning of at least one of the directional terms in a pair, you can easily know the meaning of the opposing directional term.
It’s important for you to remember the anatomical position, because that’s the standard perspective everyone uses when talking about anatomy and the directional terms. By using a standard point of reference, you can ensure that everyone will understand what you’re talking about when you refer to the anterior side of the left forearm, for example. ...
The first pair of directional terms refer to the relative position toward or away from the head. Superior (or cranial) means “ toward the head end of the body” or “higher/above.”. You can remember this because the head of a company is your superior at work. He or she holds a “higher” position than you do. They are above you in authority.
You literally “go the distance” with distal. Proximal is the opposite of distal. It means “closest to” or “nearest” the point of origin of a structure , such as your limb in relation to your trunk.
The word ventral literally means belly! Posterior (or dorsal) means the opposite of anterior: “back of” or “behind/on the back.”. This is easy to remember because “posterior” is another word for your rear end, which is on your backside. An anatomy test question might ask, “Your sternum is ________ to your spine.”.
First, let’s talk about the anatomical position. The anatomical position is a standing position, with the head facing forward and the arms to the side. The palms are facing forward with the fingers extended, and the thumbs are pointing away from the body. The feet are spaced slightly apart with the toes pointing forward.
The anatomical position also referred to as the standard anatomical position, is the consistent position of the human body in which positional reference is made for anatomical nomenclature. It is not reliant on whether the patient is standing, supine, prone, sitting, etc.
The position is defined as if the body is standing erect (hips and knees extended), head facing forward, eyes open and looking directly forwards and mouth closed. The arms are by the sides (shoulders adducted), the palms are facing forward (elbows extended and wrists supinated), and the feet parallel and together. In this position, the radius and ulna are parallel. Interestingly, due to the effect of gravity, the anatomical location of viscera is described when the patient is supine (e.g. surface anatomy of the liver).
The Terminologia Anatomica is the global standard for correct gross anatomical nomenclature 3 .
The portal vein (PV) is the main vessel of the portal venous system (PVS), which drains the blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver. There are several variants affecting the PV, and quite a number of congenital and acquired pathologies.
From an embryological point of view, the portal venous system is formed from the 4th to the 12th gestation week, developing from the vitelline venous system in close relation with the umbilical venous system.
Portosystemic shunts are diversions of portal venous blood into the systemic venous system bypassing the liver. Patients may be asymptomatic, but high-flow shunts are prone to develop hepatic encephalopathy, hepatopulmonary syndrome, and portopulmonary syndrome. Depending on the case, these shunts are managed conservatively, with trans-catheter embolization, or surgery.
In most centers, CT is the preferred technique for the evaluation of the PVS, permitting the evaluation of the portal vasculature using high-resolution isotropic acquisition in a short time, and allowing high-quality multiplanar reformations (MPR) and three-dimensional reconstructions [3]. In addition, multiphasic CT allows a comprehensive evaluation of the entire porta hepatiswith high temporal and spatial resolution. MRI can also be used to evaluate the PVS. The major advantage is the possibility to anatomically evaluate and obtain information about the contents of vascular structures without administering intravenous contrast product and non-using ionizing radiation. However, compared to CT, it is still a more time-consuming, expensive, and less accessible imaging technique, generally with less spatial and temporal resolution necessary to evaluate vascular structures, and also more susceptible to artifacts. Doppler ultrasound is a useful imaging technique in the evaluation of the PVS, is highly available, and the major advantage is allowing a detailed evaluation of the venous flow besides the anatomical information. Sometimes it is conditioned by the biotype and lack of collaboration of the patient, and still have to recur to other techniques if necessary an overall PVS assessment or dynamic contrast information.
aThe vitelline venous system arrives at the primitive liver as two paired veins (right and left), branches into the hepatic sinusoids, and then coalesce, pierce the septum tranversum(primitive diaphragm) and drain into the sinus venosus(primitive heart). These two vitelline veins communicate through three pre-hepatic anastomoses around the developing duodenum (cranial-ventral, dorsal, and caudal-ventral). bOver time, a selective involution occurs, involving the caudal part of the right vitelline vein, the cranial part of the left vitelline vein, and the caudal-ventral anastomosis. The dorsal and cranial-ventral anastomoses persist and give rise to the main PV and to the left PV, respectively. Initially, the paired umbilical veins lie more lateral than the vitelline ones, and also pierce the septum tranversumand drain into the sinus venosus. With the development of the liver, the umbilical veins fragment and connect to the hepatic sinusoids. Over time, a selective involution of the right umbilical vein and cranial portion of the left umbilical vein also occurs. cThe remnant left umbilical vein cranially bifurcates, forming two new communications: one with the IVC through the ductus venosus, carrying oxygenated blood from the placenta directly to the fetus; and another with the left PV, supplying directly the liver. After birth, the ductus venosusand the left umbilical vein involute and become the ligamentum venosumand ligamentum teres, respectively
The portal vein (PV) is the main vessel of the PVS, resulting from the confluence of the splenic and superior mesenteric veins, and drains directly into the liver, contributing to approximately 75% of its blood flow [1]. Hepatic artery provides the remaining hepatic blood flow. Once in the liver, PV ramifies and reaches the sinusoids, with downstream blood being directed to the central vein at the hepatic lobule level, then to the hepatic veins and inferior vena cava (IVC) to reach the systemic venous system.
On normal anatomy, typically, the splenic vein (SV) joins the superior mesenteric vein (SMV) anteriorly to the IVC and posteriorly to the pan creatic neck to form the PV, which ascends within the hepatoduodenal ligament, posteriorly to the hepatic artery and common bile duct, toward the hepatic hilum, where it divides into right and left (Fig. 2a). The left PV is horizontal for a short distance before it turns cranially and branches, supplying Couinaud hepatic segments I, II, III, and IV. The right PV subdivides into anterior and posterior branches; the anterior one supplying segments V and VIII, and the posterior branch supplying segments VI and VII. This typical branching pattern of the main PV occurs in 65% of individuals in the general population [2] (Fig. 2b). Additional tributaries of the PV include the left and right gastric veins, cystic veins, and Sappey veins. The inferior mesenteric vein (IMV) has greater variability, joining the splenic vein (40%), the SMV (40%), or the splenomesenteric confluence (20%) [2].
Anatomical position is the description of any region or part of the body in a specific stance. In the anatomical position, the body is upright, directly facing the observer, feet flat and directed forward. The upper limbs are at the body’s sides with the palms facing forward. Like so: Image captured in AR using Human Anatomy Atlas.
Imagine that when you’re studying a (correctly anatomically positioned) body you’re looking at a map. Like you use the cardinal directions to explain the location of certain regions (north, northwest, southeast, etc.), you use directional terms to describe the regions of the body.
Here are some commonly used directional terms: Anterior. At or near the front of the body (front view) Posterior. At or near the back of the body (back view) Midline. An imaginary vertical line that divides the body equally (right down the middle) Lateral. Farther from midline (side view)
For those of you who have taken an A&P course (or are taking one right now), you know that before you get to learning about the body you need to learn how to talk about the body. Most A&P courses begin with positions and directionals. I’m going to give you the rundown.
If you answered B) anterosuperior, you’re right! Remember, the anterior is the front view and the superior is the top view—combine the two and you’ve got yourself a bird’s-eye view of the front of the body.
In many instances, these terms can be paired. For example, a posterosuperior view combines the posterior and superior, giving us a view in which we are looking down at the back of the body, like so:
The Doppler signal of a renal transplant is the same as a normal functioning kidney. A, RI of 0.7 is considered in the upper limit of normal. Jim MacDonald, a sheep farmer, arrives at the hospital with right upper quadrant pain, fever, and elevated white blood cell count.
a. the nephron is located at the corticomedullary junction. b. the glomerulus is located in the medulla, and the remainder of the nephron penetrates the cortex. c. the glomerulus is located close to the corticomedullary junction with longer loops of Henle extending father into the medulla.
D. Tubular reabsorption adds materials to the filtrate from the blood; tubular secretion removes substances from the filtrate into the blood. A. Tubular reabsorption removes substances from the filtrate into the blood; tubular secretion adds materials to the filtrate from the blood. What serves as a barrier against trauma and the spread ...
a. tubular reabsorption removes substances from the filtrate into the blood; tubular secretion also removes substances from the filtrate into the blood. b. tubular reabsorption adds material to the filtrate from the blood; tubular secretion also adds materials to the filtrate from the blood. c. tubular reabsorption removes substances from ...