Median umbilical ligament
The median umbilical ligament is a structure in human anatomy. It is a shrivelled piece of tissue, it extends from the apex of the bladder to the umbilicus, on the deep surface of the anterior abdominal wall. It is unpaired, it is covered by the median umbilical fold. Lateral to this structure are the lateral umbilical ligament, it may be used as a landmark for surgeons who are performing laparoscopy, such as laparoscopic inguinal hernia repair. Other than this, it may be cut or removed with impunity, it contains the urachus, the obliterated form of the allantois. The allantois forms a communication between the cloaca and the outside world during embryonic development. Median umbilical ligament Anatomy figure: 36:01-01 at Human Anatomy Online, SUNY Downstate Medical Center - "The inguinal canal and derivation of the layers of the spermatic cord." Anatomy photo:44:04-0105 at the SUNY Downstate Medical Center - "The Male Pelvis: The Urinary Bladder" Anatomy image:7576 at the SUNY Downstate Medical Center Median umbilical fold Anatomy figure: 36:03-12 at Human Anatomy Online, SUNY Downstate Medical Center - "Internal surface of the anterior abdominal wall."
Common hepatic artery
The common hepatic artery is a short blood vessel that supplies oxygenated blood to the liver, pylorus of the stomach, duodenum and gallbladder. It arises from the celiac artery and has the following branches: Anatomy photo:38:03-0204 at the SUNY Downstate Medical Center - "Stomach and Liver: Contents of the Hepatoduodenal ligament" celiactrunk at The Anatomy Lesson by Wesley Norman
The placenta is a temporary organ that connects the developing fetus via the umbilical cord to the uterine wall to allow nutrient uptake, thermo-regulation, waste elimination, gas exchange via the mother's blood supply. Placentas are a defining characteristic of placental mammals, but are found in marsupials and some non-mammals with varying levels of development; the placenta functions as a fetomaternal organ with two components: the fetal placenta, which develops from the same blastocyst that forms the fetus, the maternal placenta, which develops from the maternal uterine tissue. It metabolizes a number of substances and can release metabolic products into maternal or fetal circulations; the placenta is expelled from the body upon birth of the fetus. The word placenta comes from the Latin word for a type of cake, from Greek πλακόεντα/πλακοῦντα plakóenta/plakoúnta, accusative of πλακόεις/πλακούς plakóeis/plakoús, "flat, slab-like", in reference to its round, flat appearance in humans; the classical plural is placentae, but the form placentas is common in modern English and has the wider currency at present.
Placental mammals, such as humans, have a chorioallantoic placenta that forms from the chorion and allantois. In humans, the placenta averages 22 cm in length and 2–2.5 cm in thickness, with the center being the thickest, the edges being the thinnest. It weighs 500 grams, it has crimson color. It connects to the fetus by an umbilical cord of 55–60 cm in length, which contains two umbilical arteries and one umbilical vein; the umbilical cord inserts into the chorionic plate. Vessels branch out over the surface of the placenta and further divide to form a network covered by a thin layer of cells; this results in the formation of villous tree structures. On the maternal side, these villous tree structures are grouped into lobules called cotyledons. In humans, the placenta has a disc shape, but size varies vastly between different mammalian species; the placenta takes a form in which it comprises several distinct parts connected by blood vessels. The parts, called lobes, may number two, four, or more.
Such placentas are described as bilobed/bilobular/bipartite, trilobed/trilobular/tripartite, so on. If there is a discernible main lobe and auxiliary lobe, the latter is called a succenturiate placenta. Sometimes the blood vessels connecting the lobes get in the way of fetal presentation during labor, called vasa previa. About 20,000 protein coding genes are expressed in human cells and 70% of these genes are expressed in the normal mature placenta; some 350 of these genes are more expressed in the placenta and fewer than 100 genes are placenta specific. The corresponding specific proteins are expressed in trophoblasts and have functions related to female pregnancy. Examples of proteins with elevated expression in placenta compared to other organs and tissues are PEG10 and the cancer testis antigen PAGE4 expressed in cytotrophoblasts, CSH1and KISS1 expressed in syncytiotrophoblasts, PAPPA2 and PRG2 expressed in extravillous trophoblasts; the placenta begins to develop upon implantation of the blastocyst into the maternal endometrium.
The outer layer of the blastocyst becomes the trophoblast, which forms the outer layer of the placenta. This outer layer is divided into two further layers: the underlying cytotrophoblast layer and the overlying syncytiotrophoblast layer; the syncytiotrophoblast is a multinucleated continuous cell layer that covers the surface of the placenta. It forms as a result of differentiation and fusion of the underlying cytotrophoblast cells, a process that continues throughout placental development; the syncytiotrophoblast, thereby contributes to the barrier function of the placenta. The placenta grows throughout pregnancy. Development of the maternal blood supply to the placenta is complete by the end of the first trimester of pregnancy week 14. In preparation for implantation of the blastocyst, the endometrium undergoes decidualization. Spiral arteries in the decidua are remodeled so that they become less convoluted and their diameter is increased; the increased diameter and straighter flow path both act to increase maternal blood flow to the placenta.
There is high pressure as the maternal blood fills intervillous space through these spiral arteries which bathe the fetal villi in blood, allowing an exchange of gases to take place. In humans and other hemochorial placentals, the maternal blood comes into direct contact with the fetal chorion, though no fluid is exchanged; as the pressure decreases between pulses, the deoxygenated blood flows back through the endometrial veins. Maternal blood flow is 600–700 ml/min at term; this begins at day 5 - day 12 Deoxygenated fetal blood passes through umbilical arteries to the placenta. At the junction of umbilical cord and placenta, the umbilical arteries branch radially to form chorionic arteries. Chorionic arteries, in turn, branch into cotyledon arteries. In the villi, these vessels branch to form an extensive arterio-capillary-venous system, bringing the fetal blood close to the maternal blood. Endothelin and prostanoids cause vasoconstriction in placental arteries, while nitric oxide causes vasodilation.
On the other hand, there is no neural vascular regulation, catecholamines have only little effect. The fetoplacental circulation is vulnerable to persistent hypoxia or intermittent hypoxia and
Anatomical terminology is a form of scientific terminology used by anatomists and health professionals such as doctors. Anatomical terminology uses many unique terms and prefixes deriving from Ancient Greek and Latin; these terms can be confusing to those unfamiliar with them, but can be more precise, reducing ambiguity and errors. Since these anatomical terms are not used in everyday conversation, their meanings are less to change, less to be misinterpreted. To illustrate how inexact day-to-day language can be: a scar "above the wrist" could be located on the forearm two or three inches away from the hand or at the base of the hand. By using precise anatomical terminology such ambiguity is eliminated. An international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the same prefixes and suffixes are used to add meanings to different roots; the root of a term refers to an organ or tissue. For example, the Latin names of structures such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for "two-headed", brachii as in the brachial region of the arm.
The first word describes what is being spoken about, the second describes it, the third points to location. When describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near; these landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, such as the midclavicular line from the centre of the clavicle. The cephalon or cephalic region refers to the head; this area is further differentiated into the cranium, frons, auris, nasus and mentum. The neck area is called cervical region. Examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body. For example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, is used when describing the skull.
Different terminology is used in the arms, in part to reduce ambiguity as to what the "front", "back", "inner" and "outer" surfaces are. For this reason, the terms below are used: Radial referring to the radius bone, seen laterally in the standard anatomical position. Ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet, other structures such as the eye. International morphological terminology is used by the colleges of medicine and dentistry and other areas of the health sciences, it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research and medical care. The international morphological terminology refers to morphological sciences as a biological sciences' branch. In this field, the form and structure are examined as well as the changes or developments in the organism, it is functional.
It covers the gross anatomy and the microscopic of living beings. It involves the anatomy of the adult, it includes comparative anatomy between different species. The vocabulary is extensive and complex, requires a systematic presentation. Within the international field, a group of experts reviews and discusses the morphological terms of the structures of the human body, forming today's Terminology Committee from the International Federation of Associations of Anatomists, it deals with the anatomical and embryologic terminology. In the Latin American field, there are meetings called Iberian Latin American Symposium Terminology, where a group of experts of the Pan American Association of Anatomy that speak Spanish and Portuguese and studies the international morphological terminology; the current international standard for human anatomical terminology is based on the Terminologia Anatomica. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998.
It supersedes Nomina Anatomica. Terminologia Anatomica contains terminology for about 7500 human gross anatomical structures. For microanatomy, known as histology, a similar standard exists in Terminologia Histologica, for embryology, the study of development, a standard exists in Terminologia Embryologica; these standards specify accepted names that can be used to refer to histological and embryological structures in journal articles and other areas. As of September 2016, two sections of the Terminologia Anatomica, including central nervous system and peripheral nervous system, were merged to form the Terminologia Neuroanatomica; the Terminologia Anatomica has been perceived with a considerable criticism regarding its content including coverage and spelling mistakes and errors. Anatomical terminology is chosen to highlight the relative location of body structures. For instance, an anatomist might describe one band of tissue as "inferior to" another or a physician might describe a tumor as "superficial to" a deeper body structure.
Anatomical terms used to describe location
The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta into the growing fetus. The umbilical vein provides convenient access to the central circulation of a neonate for restoration of blood volume and for administration of glucose and drugs; the blood pressure inside the umbilical vein is 20 mmHg. The unpaired umbilical vein carries oxygen and nutrient rich blood derived from fetal-maternal blood exchange at the chorionic villi. More than two-thirds of fetal hepatic circulation is via the main portal vein, while the remainder is shunted from the left portal vein via the ductus venosus to the inferior vena cava being delivered to the fetal right atrium. Closure of the umbilical vein occurs after the umbilical arteries have closed; this prolongs the communication between the placenta and fetal heart, allowing for a sort of autotransfusion of remaining blood from the placenta to the fetus. Within a week of birth, the neonate's umbilical vein is obliterated and is replaced by a fibrous cord called the round ligament of the liver.
It extends from the umbilicus to the transverse fissure, where it joins with the falciform ligament of the liver to separate segment 4 from segments 2 and 3 of the left hepatic lobe. Under extreme pressure, the round ligament may reopen to allow the passage of blood; such recanalization may be evident in patients with cirrhosis and portal hypertension. Patients with cirrhosis experience rapid growth of scar tissue in and around the liver functionally obstructing nearby vessels. Vessel occlusion increases therefore leads to hypertension. In portal hypertension, the vessels surrounding the liver are subjected to abnormally high blood pressure—so high, in fact, that the force of the blood pressing against the round ligament is sufficient to recanalize the structure; this leads to a condition called Caput medusae. A newborn baby has a patent umbilical vein for at least a week after birth; this umbilical vein may be catheterised for ready intravenous access. It may be used as a site for regular transfusion in cases of hemolytic disease.
It provides a route for measuring central venous pressure. Human umbilical vein graft Ductus venosus Gray's s139 - "Peculiarities in the vascular system of the fetus" Embryology at Temple Heart98/heart97a/sld020
The pelvis is either the lower part of the trunk of the human body between the abdomen and the thighs or the skeleton embedded in it. The pelvic region of the trunk includes the bony pelvis, the pelvic cavity, the pelvic floor, below the pelvic cavity, 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, 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 consists of the reproductive organs and the rectum, while the pelvic floor at the base of the cavity assists in supporting the organs of the abdomen. In mammals, the bony pelvis has a gap in the middle larger in females than in males, their young pass through this gap.
The pelvic region of the trunk is the lower part of the trunk, between the thighs. It includes several structures: the bony pelvis, the pelvic cavity, the pelvic floor, the perineum; the bony pelvis is the part of the skeleton embedded in the pelvic region of the trunk. It is subdivided into the pelvic spine; the pelvic girdle is composed of the appendicular hip bones oriented in a ring, connects the pelvic region of the spine to the lower limbs. The pelvic spine consists of the coccyx; the pelvic cavity defined as a small part of the space enclosed by the bony pelvis, delimited by the pelvic brim above and the pelvic floor below. Each hip bone consists of 3 sections, ilium and pubis. During childhood, these sections are separate bones, joined by the triradiate cartilage. During puberty, they fuse together to form a single bone; the pelvic cavity is a body cavity, bounded by the bones of the pelvis and which contains reproductive organs and the rectum. A distinction is made between the lesser or true pelvis inferior to the terminal line, the greater or false pelvis above it.
The pelvic inlet or superior pelvic aperture, which leads into the lesser pelvis, is bordered by the promontory, the arcuate line of ilium, the iliopubic eminence, the pecten of the pubis, the upper part of the pubic symphysis. The pelvic outlet or inferior pelvic aperture is the region between the subpubic angle or pubic arch, the ischial tuberosities and the coccyx. Ligaments: obturator membrane, inguinal ligament Alternatively, the pelvis is divided into three planes: the inlet and outlet; the pelvic floor has two inherently conflicting functions: One is to close the pelvic and abdominal cavities and bear the load of the visceral organs. To achieve both these tasks, the pelvic floor is composed of several overlapping sheets of muscles and connective tissues; the pelvic diaphragm is composed of the coccygeus muscle. These arise between the symphysis and the ischial spine and converge on the coccyx and the anococcygeal ligament which spans between the tip of the coccyx and the anal hiatus; this leaves a slit for the urogenital openings.
Because of the width of the genital aperture, wider in females, a second closing mechanism is required. The urogenital diaphragm consists of the deep transverse perineal which arises from the inferior ischial and pubic rami and extends to the urogential hiatus; the urogenital diaphragm is reinforced posteriorly by the superficial transverse perineal. The external anal and urethral sphincters close the urethra; the former is surrounded by the bulbospongiosus which narrows the vaginal introitus in females and surrounds the corpus spongiosum in males. Ischiocavernosus clitoridis. Modern humans are to a large extent characterized by large brains; because the pelvis is vital to both locomotion and childbirth, natural selection has been confronted by two conflicting demands: a wide birth canal and locomotion efficiency, a conflict referred to as the "obstetrical dilemma". The female pelvis, or gynecoid pelvis, has evolved to its maximum width for childbirth—a wider pelvis would make women unable to walk.
In contrast, human male pelvises are not constrained by the need to give birth and therefore are more optimized for bipedal locomotion. The principal differences between male and female true and false pelvis include: The female pelvis is larger and broader than the male pelvis, taller and more compact; the female inlet is oval in shape, while the male sacral promontory projects further. The sides of the male pelvis converge from the inlet to the outlet, whereas the sides of the female pelvis are wider apart; the angle between