|
Vitelline Veins
The vitelline veins are veins that drain blood from the yolk sac and the gut tube during gestation. Path They run upward at first in front, and subsequently on either side of the intestinal canal. They unite on the ventral aspect of the canal. Beyond this, they are connected to one another by two anastomotic branches, one on the dorsal, and the other on the ventral aspect of the duodenal portion of the intestine. This is encircled by two venous rings; into the middle or dorsal anastomosis the superior mesenteric vein opens. The portions of the veins above the upper ring become interrupted by the developing liver and broken up by it into a plexus of small capillary-like vessels termed sinusoids. Derivatives The vitelline veins give rise to: * Hepatic veins * Inferior portion of Inferior vena cava * Portal vein * Superior mesenteric vein * Inferior mesenteric vein The branches conveying the blood to the plexus are named the venae advehentes, and become the branches of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venae Revehentes
The vitelline veins are veins that drain blood from the yolk sac and the gut tube during gestation. Path They run upward at first in front, and subsequently on either side of the intestinal canal. They unite on the ventral aspect of the canal. Beyond this, they are connected to one another by two anastomotic branches, one on the dorsal, and the other on the ventral aspect of the duodenal portion of the intestine. This is encircled by two venous rings; into the middle or dorsal anastomosis the superior mesenteric vein opens. The portions of the veins above the upper ring become interrupted by the developing liver and broken up by it into a plexus of small capillary-like vessels termed sinusoids. Derivatives The vitelline veins give rise to: * Hepatic veins * Inferior portion of Inferior vena cava * Portal vein * Superior mesenteric vein * Inferior mesenteric vein The branches conveying the blood to the plexus are named the venae advehentes, and become the branches of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver
The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it is located in the right upper quadrant of the abdomen, below the diaphragm. Its other roles in metabolism include the regulation of glycogen storage, decomposition of red blood cells, and the production of hormones. The liver is an accessory digestive organ that produces bile, an alkaline fluid containing cholesterol and bile acids, which helps the breakdown of fat. The gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver which is later moved to the small intestine to complete digestion. The liver's highly specialized tissue, consisting mostly of hepatocytes, regulates a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex molecule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinusoids
A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: they convey blood between the arterioles and venules. These microvessels are the site of exchange of many substances with the interstitial fluid surrounding them. Substances which cross capillaries include water, oxygen, carbon dioxide, urea, glucose, uric acid, lactic acid and creatinine. Lymph capillaries connect with larger lymph vessels to drain lymphatic fluid collected in the microcirculation. During early embryonic development, new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a '' de novo'' production of endothelial cells that then form vascular tubes. The term ''angiogenesis'' denotes the formation of new capillaries from pre-existing blood vessels and already present en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Embryonic Development
Human embryonic development, or human embryogenesis, is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences. Embryonic development in the human, covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus. Human embryology is the study of this development during the first eight weeks after fertilization. The normal period of gestation (pregnancy) is about nine months or 40 weeks. The germinal stage refers to the time from fertilization throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatic Veins
In human anatomy, the hepatic veins are the veins that drain venous blood from the liver into the inferior vena cava (as opposed to the hepatic portal vein which conveys blood from the gastrointestinal organs to the liver). There are usually three large upper hepatic veins draining from the left, middle, and right parts of the liver, as well as a number (6-20) of lower hepatic veins. All hepatic veins are valveless. Structure All the hepatic veins drain into the inferior vena cava. The hepatic veins are divided into an upper and a lower group. Upper group The upper group consists of three hepatic veins - the right, middle, and left hepatic veins - draining the central veins from the right, middle, and left regions of the liver and are larger than the lower group of veins. The veins of the upper group drain into the suprahepatic part of the inferior vena cava (i.e. part superior to the liver). Right hepatic vein The right hepatic vein is the longest and largest of all the he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Mesenteric Vein
In human anatomy, the superior mesenteric vein (SMV) is a blood vessel that drains blood from the small intestine (jejunum and ileum). Behind the neck of the pancreas, the superior mesenteric vein combines with the splenic vein to form the hepatic portal vein. The superior mesenteric vein lies to the right of the similarly named artery, the superior mesenteric artery, which originates from the abdominal aorta. Structure Tributaries of the superior mesenteric vein drain the small intestine, large intestine, stomach, pancreas and appendix and include: * Right gastro-omental vein (also known as the right gastro-epiploic vein) * inferior pancreaticoduodenal veins * veins from jejunum * veins from ileum * middle colic vein – drains the transverse colon * right colic vein – drains the ascending colon * ileocolic vein The superior mesenteric vein combines with the splenic vein to form the portal vein. Clinical significance Thrombosis of the superior mesenteric vein is quite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Vena Cava
The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the fifth lumbar vertebra. The inferior vena cava is the lower (" inferior") of the two venae cavae, the two large veins that carry deoxygenated blood from the body to the right atrium of the heart: the inferior vena cava carries blood from the lower half of the body whilst the superior vena cava carries blood from the upper half of the body. Together, the venae cavae (in addition to the coronary sinus, which carries blood from the muscle of the heart itself) form the venous counterparts of the aorta. It is a large retroperitoneal vein that lies posterior to the abdominal cavity and runs along the right side of the vertebral column. It enters the right auricle at the lower right, back side of the heart. The name derives from la, ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatic Veins
In human anatomy, the hepatic veins are the veins that drain venous blood from the liver into the inferior vena cava (as opposed to the hepatic portal vein which conveys blood from the gastrointestinal organs to the liver). There are usually three large upper hepatic veins draining from the left, middle, and right parts of the liver, as well as a number (6-20) of lower hepatic veins. All hepatic veins are valveless. Structure All the hepatic veins drain into the inferior vena cava. The hepatic veins are divided into an upper and a lower group. Upper group The upper group consists of three hepatic veins - the right, middle, and left hepatic veins - draining the central veins from the right, middle, and left regions of the liver and are larger than the lower group of veins. The veins of the upper group drain into the suprahepatic part of the inferior vena cava (i.e. part superior to the liver). Right hepatic vein The right hepatic vein is the longest and largest of all the he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
