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Inferior Vena Cava Valve
The valve of the inferior vena cava (Eustachian valve) is a venous valve that lies at the junction of the inferior vena cava and right atrium. Development In prenatal development, the eustachian valve helps direct the flow of oxygen-rich blood through the right atrium into the left atrium and away from the right ventricle. Before birth, the fetal circulation directs oxygen-rich blood returning from the placenta to mix with blood from the hepatic veins in the inferior vena cava. Streaming this blood across the atrial septum via the foramen ovale increases the oxygen content of blood in the left atrium. This in turn increases the oxygen concentration of blood in the left ventricle, the aorta, the coronary circulation and the circulation of the developing brain. Following birth and separation from the placenta, the oxygen content in the inferior vena cava falls. With the onset of breathing, the left atrium receives oxygen-rich blood from the lungs via the pulmonary veins. As b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart
The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the thorax, chest, called the mediastinum. In humans, the heart is divided into four chambers: upper left and right Atrium (heart), atria and lower left and right Ventricle (heart), ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent cardiac regurgitation, backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatic Vein
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] |
Bartolomeo Eustachi
Bartolomeo Eustachi (27 August 1574), also known as Eustachio or by his Latin name of Bartholomaeus Eustachius (), was an Italian anatomist and one of the founders of the science of human anatomy. Biography Bartolomeo was born in San Severino in the province of Ancona, where his father, Marinao Eustachius, was a wealthy and prominent physician. Bartolomeo received the required broad humanistic education typical of that time, and then studied medicine at the Archiginnasio della Sapienza in Rome. He was also well versed in Hebrew, Arabic, and Greek, which gave him access to original medical treatises written in those languages. As a physician, Eustachius enjoyed great prestige among the upper classes, having among his patients the Duke of Urbino, the Cardinal della Rovero, and the Duke of Terranova. He became a member of the Medical College of Rome and in 1549 was appointed Professor of Anatomy at the Papal College, the Archiginnasio dell Sapienza. He soon obtained papal dispe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly. Signs and symptoms of stroke may include an hemiplegia, inability to move or feel on one side of the body, receptive aphasia, problems understanding or expressive aphasia, speaking, dizziness, or homonymous hemianopsia, loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than 24 hours, the stroke is a transient ischemic attack (TIA), also called a mini-stroke. subarachnoid hemorrhage, Hemorrhagic stroke may also be associated with a thunderclap headache, severe headache. The symptoms of stroke can be permanent. Long-term complications may include pneumonia and Urinary incontinence, loss of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patent Foramen Ovale
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA). After PFO closure the atria normally are separated by a dividing wall, the interatrial septum. If this septum is defective or absent, then oxygen-rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart; or the opposite, depending on whether the left or right atrium has the higher blood pressure. In the absence of other heart defects, the left atrium has the higher pressure. This can lead to lower-than-normal oxygen levels in the arterial blood that supplies the brain, organs, and tissues. However, an ASD m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Vena Cava
The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein that receives venous return from the upper half of the body, above the diaphragm. Venous return from the lower half, below the diaphragm, flows through the inferior vena cava. The SVC is located in the anterior right superior mediastinum. It is the typical site of central venous access via a central venous catheter or a peripherally inserted central catheter. Mentions of "the cava" without further specification usually refer to the SVC. Structure The superior vena cava is formed by the left and right brachiocephalic veins, which receive blood from the upper limbs, head and neck, behind the lower border of the first right costal cartilage. It passes vertically downwards behind the first intercostal space and receives the azygos vei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cor Triatriatum
Cor triatriatum (or triatrial heart) is a congenital heart defect where the left atrium (cor triatriatum sinistrum) or right atrium (cor triatriatum dextrum) is subdivided by a thin membrane, resulting in three atrial chambers (hence the name). Cor triatriatum represents 0.1% of all congenital cardiac malformations and may be associated with other cardiac defects in as many as 50% of cases. The membrane may be complete or may contain one or more fenestrations of varying size. Cor triatriatum sinistrum is more common. In this defect, there is typically a proximal chamber that receives the pulmonic veins and a distal (true) chamber located more anteriorly where it empties into the mitral valve. The membrane that separates the atrium into two parts varies significantly in size and shape. It may appear similar to a diaphragm or be funnel-shaped, band-like, entirely intact (imperforate) or contain one or more openings (fenestrations) ranging from small, restrictive-type to large an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. The time interval of a gestation is called the '' gestation period''. In obstetrics, '' gestational age'' refers to the time since the onset of the last menses, which on average is fertilization age plus two weeks. Mammals In mammals, pregnancy begins when a zygote (fertilized ovum) implants in the female's uterus and ends once the fetus leaves the uterus during labor or an abortion (whether induced or spontaneous). Humans In humans, pregnancy can be defined clinically, biochemically or biologically. Clinically, pregnancy starts from first day of the mother's last period. Biochemically, pregnancy starts when a woman's human chorionic gonado ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placenta
The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal physiology during pregnancy. The placenta connects to the fetus via the umbilical cord, and on the opposite aspect to the maternal uterus in a species-dependent manner. In humans, a thin layer of maternal decidual ( endometrial) tissue comes away with the placenta when it is expelled from the uterus following birth (sometimes incorrectly referred to as the 'maternal part' of the placenta). Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development. Mammalian placentas probably first evolved abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eustachian Valve
The valve of the inferior vena cava (Eustachian valve) is a venous valve that lies at the junction of the inferior vena cava and right atrium. Development In prenatal development, the eustachian valve helps direct the flow of oxygen-rich blood through the right atrium into the left atrium and away from the right ventricle. Before birth, the fetal circulation directs oxygen-rich blood returning from the placenta to mix with blood from the hepatic veins in the inferior vena cava. Streaming this blood across the atrial septum via the foramen ovale increases the oxygen content of blood in the left atrium. This in turn increases the oxygen concentration of blood in the left ventricle, the aorta, the coronary circulation and the circulation of the developing brain. Following birth and separation from the placenta, the oxygen content in the inferior vena cava falls. With the onset of breathing, the left atrium receives oxygen-rich blood from the lungs via the pulmonary veins. As b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fetal Circulation
In humans, the circulatory system is different before and after birth. The fetal circulation is composed of the placenta, umbilical blood vessels encapsulated by the umbilical cord, heart and systemic blood vessels. A major difference between the fetal circulation and postnatal circulation is that the lungs are not used during the fetal stage resulting in the presence of shunts to move oxygenated blood and nutrients from the placenta to the fetal tissue. At birth, the start of breathing and the severance of the umbilical cord prompt various changes that quickly transform fetal circulation into postnatal circulation. Oxygenation, nutrient, and waste exchange Placenta The placenta functions as the exchange site of nutrients and wastes between the maternal and fetal circulation. Water, glucose, amino acids, vitamins, and inorganic salts freely diffuse across the placenta along with oxygen. Two umbilical arteries carry systemic arterial blood from the fetus to the placenta where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains proteins, glucose, mineral ions, and hormones. The blood cells are mainly red blood cells (erythrocytes), white blood cells (leukocytes), and (in mammals) platelets (thrombocytes). The most abundant cells are red blood cells. These contain hemoglobin, which facilitates oxygen transport by reversibly binding to it, increasing its solubility. Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Blood is circulated around the body through blood vessels by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
