Placenta<\/h3>\n<\/span>\n\n\nThe placenta is a temporary feto-maternal organ providing the interchange between mother and fetus. It is a circular discoidal organ, which at term measures about 22cm with an average weight of 500gr.<\/p>\n\n\n\n![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2020\/01\/placenta-600x311.png\")
<\/a>The placenta<\/strong> (Credit: OpenStax, CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nDivisions<\/h4>\n<\/span>\n\n\nThe placenta is divided into 2 surfaces: the fetal<\/strong> and the maternal surfaces<\/strong>.<\/p>\n\n\n\n- The fetal surface, which is represented by the chorionic plate, is covered by the amnion and provides the attachment site to the umbilical cord.<\/li>
- Representing the maternal surface of the placenta, the basal plate emerges from the uterine wall during delivery.<\/li><\/ul>\n\n\n<\/span>\n
Structures<\/h4>\n<\/span>\n\n\nThe placenta is composed of a series of placental cotyledons, each one having different villous and vessel branches (villous trees), described as follows:<\/p>\n\n\n\n
- Stem villi<\/strong>.\u00a0Connected to the chorionic plate, these are characterized by a condensed fibrous stroma containing large vessels and microvessels. Its main function is support the villous trees.<\/li>
- Immature intermediate villi.<\/strong>\u00a0Representing the continuations of stem villi, these are bulbous, peripheral, more prominent vessels considered the growth centers of the villous trees.<\/li>
- Mature intermediate villi.<\/strong>\u00a0These are long, slender, peripheral ramifications from which the terminal villi develop.<\/li>
- Terminal (floating) villi<\/strong>.\u00a0Arise from the mature intermediate villi. These are grape-like structures characterized by a high degree of capillarization and highly dilated sinusoids. They are the site at which most of the nutrient and oxygen exchange occurs.<\/li>
- Mesenchymal villi<\/strong>.\u00a0These are the most primitive type of villi during the early stages of pregnancy, allowing villous proliferation and production of all endocrine activities. As pregnancy progresses, they sustain villous growth.<\/li><\/ul>\n\n\n<\/span>\n
Clinical Information<\/h4>\n<\/span>\n\n\nThe placenta can be the center of attention in different obstetrical complications, including:<\/p>\n\n\n\n
- Placenta previa<\/strong>.\u00a0Occurs when the placenta implants itself low in the uterus, specifically in or near the cervix.<\/li>
- Placental abruption.<\/strong>\u00a0Occurs when the placenta separates from the uterus before labor.<\/li><\/ul>\n\n\n<\/span>\n
Umbilical cord<\/h3>\n<\/span>\n\n\nThe umbilical cord is a helical and tubular blood conduit that connects the fetus to the placenta, allowing the nutrient exchange between the mother and the unborn child. At term, the umbilical cord has an average length of 50-60 cm, considering a normal length to go from 30 cm to 100 cm.<\/p>\n\n\n\n![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2020\/01\/umbilical_cord-600x523.png\")
<\/a>The umbilical cord and a summary of the fetal circulation<\/strong> (Credit: OpenStax, CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nStructures<\/h4>\n<\/span>\n\n\nThe fully developed umbilical cord normally contains 2 umbilical arteries<\/strong>, 1 umbilical vein<\/strong>, the remnant of the allantois<\/strong> all embedded in Wharton\u2019s jelly<\/strong> and surrounded by a single layer of amnion. The area of the umbilical cord vein is approximately 30% larger than the combined areas of the arteries.<\/p>\n\n\n\n- The umbilical cord vein<\/strong> transports oxygenated blood to the fetus by entering into the fetal abdomen at the umbilicus and arriving at the liver, which then drains into the inferior vena cava.<\/li>
- The arteries<\/strong> return oxygen-depleted blood to the placenta, arriving at the decidua (gestational endometrium), which then enters the maternal systemic circulation.<\/li>
- Wharton\u2019s jelly is a mucous-rich substance serving to protect the contents and prevent kinking of the cord.<\/li><\/ul>\n\n\n<\/span>\n
Clinical Information<\/h4>\n<\/span>\n\n\n- Umbilical cord prolapse<\/strong>.\u00a0Occurs when the umbilical cord comes out of the uterus with or before the presenting part of the fetus.<\/li>
- Umbilical cord entanglement<\/strong>. A\u00a0condition that can mean either one or more loops of the cord being encircled around any part of the fetal body or two umbilical cords getting entangled with each other.<\/li><\/ul>\n\n\n<\/span>\n
Neurovasculature<\/h3>\n<\/span>\n\n\n- Blood supply<\/strong>
- Maternal oxygenated is supplied by the uterine arteries<\/strong>. <\/li>
- Blood enters the placenta through the basal plate endometrial arteries (spiral arteries<\/strong>), perfuses intervillous spaces, and flows in the intervillous space, allowing nutrient and oxygen exchange.<\/li><\/ul><\/li>
- Venous drainage<\/strong>
- On its return, deoxygenated blood traverses through the placental intervillous space and drains back through venous orifices in the basal plate, returning to the maternal systemic circulation through the uterine veins<\/strong>.<\/li><\/ul><\/li>
- Innervation<\/strong>
- The placenta is the only human organ without innervation. A small part of the umbilical cord proximal to the fetus has some innervation.<\/li>
- The growth of nervous tissue is inhibited in all gestational uterine tissues by the invading trophoblast and spiral artery remodeling.<\/li><\/ul><\/li>
- Lymphatics<\/strong>
- The umbilical cord contains no lymphatic vessels, and to this day, no lymphatic drainage was found in the placenta.<\/li><\/ul><\/li><\/ul>\n<\/span>
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2020\/01\/placenta.png\")
<\/a>Divisions<\/h4>\n<\/span>\n\n\nThe placenta is divided into 2 surfaces: the fetal<\/strong> and the maternal surfaces<\/strong>.<\/p>\n\n\n\n- The fetal surface, which is represented by the chorionic plate, is covered by the amnion and provides the attachment site to the umbilical cord.<\/li>
- Representing the maternal surface of the placenta, the basal plate emerges from the uterine wall during delivery.<\/li><\/ul>\n\n\n<\/span>\n
Structures<\/h4>\n<\/span>\n\n\nThe placenta is composed of a series of placental cotyledons, each one having different villous and vessel branches (villous trees), described as follows:<\/p>\n\n\n\n
- Stem villi<\/strong>.\u00a0Connected to the chorionic plate, these are characterized by a condensed fibrous stroma containing large vessels and microvessels. Its main function is support the villous trees.<\/li>
- Immature intermediate villi.<\/strong>\u00a0Representing the continuations of stem villi, these are bulbous, peripheral, more prominent vessels considered the growth centers of the villous trees.<\/li>
- Mature intermediate villi.<\/strong>\u00a0These are long, slender, peripheral ramifications from which the terminal villi develop.<\/li>
- Terminal (floating) villi<\/strong>.\u00a0Arise from the mature intermediate villi. These are grape-like structures characterized by a high degree of capillarization and highly dilated sinusoids. They are the site at which most of the nutrient and oxygen exchange occurs.<\/li>
- Mesenchymal villi<\/strong>.\u00a0These are the most primitive type of villi during the early stages of pregnancy, allowing villous proliferation and production of all endocrine activities. As pregnancy progresses, they sustain villous growth.<\/li><\/ul>\n\n\n<\/span>\n
Clinical Information<\/h4>\n<\/span>\n\n\nThe placenta can be the center of attention in different obstetrical complications, including:<\/p>\n\n\n\n
- Placenta previa<\/strong>.\u00a0Occurs when the placenta implants itself low in the uterus, specifically in or near the cervix.<\/li>
- Placental abruption.<\/strong>\u00a0Occurs when the placenta separates from the uterus before labor.<\/li><\/ul>\n\n\n<\/span>\n
Umbilical cord<\/h3>\n<\/span>\n\n\nThe umbilical cord is a helical and tubular blood conduit that connects the fetus to the placenta, allowing the nutrient exchange between the mother and the unborn child. At term, the umbilical cord has an average length of 50-60 cm, considering a normal length to go from 30 cm to 100 cm.<\/p>\n\n\n\n<\/a>The umbilical cord and a summary of the fetal circulation<\/strong> (Credit: OpenStax, CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nStructures<\/h4>\n<\/span>\n\n\nThe fully developed umbilical cord normally contains 2 umbilical arteries<\/strong>, 1 umbilical vein<\/strong>, the remnant of the allantois<\/strong> all embedded in Wharton\u2019s jelly<\/strong> and surrounded by a single layer of amnion. The area of the umbilical cord vein is approximately 30% larger than the combined areas of the arteries.<\/p>\n\n\n\n- The umbilical cord vein<\/strong> transports oxygenated blood to the fetus by entering into the fetal abdomen at the umbilicus and arriving at the liver, which then drains into the inferior vena cava.<\/li>
- The arteries<\/strong> return oxygen-depleted blood to the placenta, arriving at the decidua (gestational endometrium), which then enters the maternal systemic circulation.<\/li>
- Wharton\u2019s jelly is a mucous-rich substance serving to protect the contents and prevent kinking of the cord.<\/li><\/ul>\n\n\n<\/span>\n
Clinical Information<\/h4>\n<\/span>\n\n\n- Umbilical cord prolapse<\/strong>.\u00a0Occurs when the umbilical cord comes out of the uterus with or before the presenting part of the fetus.<\/li>
- Umbilical cord entanglement<\/strong>. A\u00a0condition that can mean either one or more loops of the cord being encircled around any part of the fetal body or two umbilical cords getting entangled with each other.<\/li><\/ul>\n\n\n<\/span>\n
Neurovasculature<\/h3>\n<\/span>\n\n\n- Blood supply<\/strong>
- Maternal oxygenated is supplied by the uterine arteries<\/strong>. <\/li>
- Blood enters the placenta through the basal plate endometrial arteries (spiral arteries<\/strong>), perfuses intervillous spaces, and flows in the intervillous space, allowing nutrient and oxygen exchange.<\/li><\/ul><\/li>
- Venous drainage<\/strong>
- On its return, deoxygenated blood traverses through the placental intervillous space and drains back through venous orifices in the basal plate, returning to the maternal systemic circulation through the uterine veins<\/strong>.<\/li><\/ul><\/li>
- Innervation<\/strong>
- The placenta is the only human organ without innervation. A small part of the umbilical cord proximal to the fetus has some innervation.<\/li>
- The growth of nervous tissue is inhibited in all gestational uterine tissues by the invading trophoblast and spiral artery remodeling.<\/li><\/ul><\/li>
- Lymphatics<\/strong>
- The umbilical cord contains no lymphatic vessels, and to this day, no lymphatic drainage was found in the placenta.<\/li><\/ul><\/li><\/ul>\n<\/span>
- The fetal surface, which is represented by the chorionic plate, is covered by the amnion and provides the attachment site to the umbilical cord.<\/li>
- Representing the maternal surface of the placenta, the basal plate emerges from the uterine wall during delivery.<\/li><\/ul>\n\n\n<\/span>\n
Structures<\/h4>\n<\/span>\n\n\n
The placenta is composed of a series of placental cotyledons, each one having different villous and vessel branches (villous trees), described as follows:<\/p>\n\n\n\n
- Stem villi<\/strong>.\u00a0Connected to the chorionic plate, these are characterized by a condensed fibrous stroma containing large vessels and microvessels. Its main function is support the villous trees.<\/li>
- Immature intermediate villi.<\/strong>\u00a0Representing the continuations of stem villi, these are bulbous, peripheral, more prominent vessels considered the growth centers of the villous trees.<\/li>
- Mature intermediate villi.<\/strong>\u00a0These are long, slender, peripheral ramifications from which the terminal villi develop.<\/li>
- Terminal (floating) villi<\/strong>.\u00a0Arise from the mature intermediate villi. These are grape-like structures characterized by a high degree of capillarization and highly dilated sinusoids. They are the site at which most of the nutrient and oxygen exchange occurs.<\/li>
- Mesenchymal villi<\/strong>.\u00a0These are the most primitive type of villi during the early stages of pregnancy, allowing villous proliferation and production of all endocrine activities. As pregnancy progresses, they sustain villous growth.<\/li><\/ul>\n\n\n<\/span>\n
Clinical Information<\/h4>\n<\/span>\n\n\n
The placenta can be the center of attention in different obstetrical complications, including:<\/p>\n\n\n\n
- Placenta previa<\/strong>.\u00a0Occurs when the placenta implants itself low in the uterus, specifically in or near the cervix.<\/li>
- Placental abruption.<\/strong>\u00a0Occurs when the placenta separates from the uterus before labor.<\/li><\/ul>\n\n\n<\/span>\n
Umbilical cord<\/h3>\n<\/span>\n\n\n
The umbilical cord is a helical and tubular blood conduit that connects the fetus to the placenta, allowing the nutrient exchange between the mother and the unborn child. At term, the umbilical cord has an average length of 50-60 cm, considering a normal length to go from 30 cm to 100 cm.<\/p>\n\n\n\n
<\/a>The umbilical cord and a summary of the fetal circulation<\/strong> (Credit: OpenStax, CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\n Structures<\/h4>\n<\/span>\n\n\n
The fully developed umbilical cord normally contains 2 umbilical arteries<\/strong>, 1 umbilical vein<\/strong>, the remnant of the allantois<\/strong> all embedded in Wharton\u2019s jelly<\/strong> and surrounded by a single layer of amnion. The area of the umbilical cord vein is approximately 30% larger than the combined areas of the arteries.<\/p>\n\n\n\n
- The umbilical cord vein<\/strong> transports oxygenated blood to the fetus by entering into the fetal abdomen at the umbilicus and arriving at the liver, which then drains into the inferior vena cava.<\/li>
- The arteries<\/strong> return oxygen-depleted blood to the placenta, arriving at the decidua (gestational endometrium), which then enters the maternal systemic circulation.<\/li>
- Wharton\u2019s jelly is a mucous-rich substance serving to protect the contents and prevent kinking of the cord.<\/li><\/ul>\n\n\n<\/span>\n
Clinical Information<\/h4>\n<\/span>\n\n\n
- Umbilical cord prolapse<\/strong>.\u00a0Occurs when the umbilical cord comes out of the uterus with or before the presenting part of the fetus.<\/li>
- Umbilical cord entanglement<\/strong>. A\u00a0condition that can mean either one or more loops of the cord being encircled around any part of the fetal body or two umbilical cords getting entangled with each other.<\/li><\/ul>\n\n\n<\/span>\n
Neurovasculature<\/h3>\n<\/span>\n\n\n
- Blood supply<\/strong>
- Maternal oxygenated is supplied by the uterine arteries<\/strong>. <\/li>
- Blood enters the placenta through the basal plate endometrial arteries (spiral arteries<\/strong>), perfuses intervillous spaces, and flows in the intervillous space, allowing nutrient and oxygen exchange.<\/li><\/ul><\/li>
- Venous drainage<\/strong>
- On its return, deoxygenated blood traverses through the placental intervillous space and drains back through venous orifices in the basal plate, returning to the maternal systemic circulation through the uterine veins<\/strong>.<\/li><\/ul><\/li>
- Innervation<\/strong>
- The placenta is the only human organ without innervation. A small part of the umbilical cord proximal to the fetus has some innervation.<\/li>
- The growth of nervous tissue is inhibited in all gestational uterine tissues by the invading trophoblast and spiral artery remodeling.<\/li><\/ul><\/li>
- Lymphatics<\/strong>
- The umbilical cord contains no lymphatic vessels, and to this day, no lymphatic drainage was found in the placenta.<\/li><\/ul><\/li><\/ul>\n<\/span>
- Innervation<\/strong>
- Blood enters the placenta through the basal plate endometrial arteries (spiral arteries<\/strong>), perfuses intervillous spaces, and flows in the intervillous space, allowing nutrient and oxygen exchange.<\/li><\/ul><\/li>
- Maternal oxygenated is supplied by the uterine arteries<\/strong>. <\/li>
- Umbilical cord entanglement<\/strong>. A\u00a0condition that can mean either one or more loops of the cord being encircled around any part of the fetal body or two umbilical cords getting entangled with each other.<\/li><\/ul>\n\n\n<\/span>\n
- The arteries<\/strong> return oxygen-depleted blood to the placenta, arriving at the decidua (gestational endometrium), which then enters the maternal systemic circulation.<\/li>
- Placental abruption.<\/strong>\u00a0Occurs when the placenta separates from the uterus before labor.<\/li><\/ul>\n\n\n<\/span>\n
- Immature intermediate villi.<\/strong>\u00a0Representing the continuations of stem villi, these are bulbous, peripheral, more prominent vessels considered the growth centers of the villous trees.<\/li>
- Stem villi<\/strong>.\u00a0Connected to the chorionic plate, these are characterized by a condensed fibrous stroma containing large vessels and microvessels. Its main function is support the villous trees.<\/li>