What is epitheliochorial placenta?
The epitheliochorial placenta involves six tissue barriers between the foetal and maternal circulation. It is the primitive type from which others have been derived and is seen in pig, sow, mare, horse, cattle etc. ii. Syndesmochorial Placenta:
What is chorionic placenta?
Also found in: Dictionary, Thesaurus, Encyclopedia. a placenta in which the chorionic tissue penetrates to the endothelium of the maternal blood vessels. A placenta in which the syncytial trophoblasts of the chorion penetrate to the blood vessels of the uterus.
What is cotyledonary placenta?
Cotyledonary Placenta: In this type of placenta the villi become aggregated in special regions or patches to form small tufts. The rest part of the chorion surface remains smooth. It is seen in ruminant (cud-chewing) ungulates such as cattle, sheep, deer etc.
What is meta-discoidal placenta?
Meta-Discoidal Placenta: In primates a special type of discoidal placenta is seen where the villi are at first scattered all over the chorion but later becomes restricted to one or two discs. The mono-discoidal type with a single disc is seen in man, while the bi-discoidal type with two disc shaped villous areas is seen in monkeys. Type # 4.
What is Syndesmochorial?
(sin″dez″mŏ-kō′rē-ăl) Pert. to a type of placenta in which there is destruction of the surface layer of the uterine mucosa, thus allowing chorionic villi to come into direct contact with maternal blood vessels.
What is Syndesmochorial placenta anatomy?
camels and ruminants possess a syndesmochorial placenta, in which the epithelium of the maternal tissues is eroded to facilitate intercommunication.
What are the four types of placenta?
There are four main placenta types recognized by gross morphology and whether the maternal-fetal exchange area is found over all the available surface of the chorionic sac or whether it is restricted; Diffuse (horses, pigs), Multicotyledonary (ruminants), Zonary (carnivores), Discoid/Bidiscoid (primates, rodents, ...
What are the 2 types of placenta?
Mammalian placentas are classified into two types according to the fetal membrane including to chorion, yolk sac placenta (choriovitelline placenta) and chorioallantoic placenta.
What are the types of placenta abnormalities?
These placental disorders are called placenta previa, placenta accreta, placenta increta or placenta percreta. Placental disorders are usually diagnosed by ultrasound in the second trimester (about 18 to 20 weeks into a pregnancy). Placenta previa occurs when the placenta covers some or all of the cervix.
How many types of placenta are there during pregnancy?
Posterior placenta: The placenta develops in the back of the uterine wall, where the fertilized egg is attached. Anterior placenta: The placenta adheres to the front wall of the uterus, and the fetus develops behind it. Fundal placenta: This occurs when the placenta attaches to the upper wall of your uterus.
What type of placenta is most common?
The type is determined by how deeply the placenta is attached to the uterus. Placenta accreta: The placenta firmly attaches to the wall of the uterus. It does not pass through the wall of the uterus or impact the muscles of the uterus. This is the most common type of the condition.
Which placenta position is best for normal delivery?
This is because having the placenta on the back wall of the uterus means feeling the baby s movements and kicks early and stronger. Moreover, posterior placenta is considered to be the best for the baby as it allows the baby to grow and descend to the right position and align in the birth canal for a vaginal birth.
What are signs of placenta problems?
SymptomsVaginal bleeding, although there might not be any.Abdominal pain.Back pain.Uterine tenderness or rigidity.Uterine contractions, often coming one right after another.
What are the 3 layers of the placenta?
Amniotic layer is composed of a single-celled epithelial layer and a deeper mesodermal layer. Chorionic layer is composed of a mesodermal layer and a trophoblast layer.
What is anterior placenta gender?
According to some, having an anterior placenta means you're having a girl, whereas a posterior placenta means you're having a boy.
What size is the placenta at 10 weeks?
At as early as 10 weeks, the placenta can be picked up on an ultrasound. By halfway through a healthy pregnancy, it's about 15 centimetres in diameter (the size of a side plate), and by the end it doubles to become about the size of a Frisbee and the weight of a block and a half of butter.
What is the Deciduate placenta?
Deciduate (Deciduos) placenta – Implantation is more intimate; the wall of. the uterus become eroded so that the fetal chorionic epithelium may come. to lie either in the connective tissue or into the maternal blood and at the. time of parturation when fetal part separate from the uterine part of the.
What is endothelial Chorial placenta?
A placenta in which the syncytial trophoblasts of the chorion penetrate to the blood vessels of the uterus. See also: placenta.
What is Endotheliochorial placenta?
The endotheliochorial placenta as a definitive form has an interhemal area consisting of maternal endothelium, interstitial lamina, trophoblast, individual or conjoint basal laminas, and fetal endothelium.
What is Cotyledonary placenta?
The Artiodactyla have a cotyledonary placenta. In this form of placenta the chorionic villi form a number of separate circular structures (cotyledons) which are distributed over the surface of the chorionic sac. Sheep, goats and cattle have between 72 and 125 cotyledons whereas deer have 4-6 larger cotyledons.
What is the placenta in salpae?
In salpae, the placenta is formed with the participation of follicular epithelial cells that intermix with rudiments of embryonic organs and function as an intermediary between the organs and the maternal organism.
What is the name of the placenta that grows into the villi?
Blood vessels of the yolk sac or allantois usually grow into the villi. Accordingly, vitelline and chorioallantoic placentas are distinguished. A vitelline placenta characterizes most marsupials and some fishes (Selachii), amphibians, and reptiles (a chorioallantoic placenta forms in some reptiles).
What are the rudiments of the placenta?
Seed rudiments, such as ovules and megasporangia, are attached to the placenta. In ferns, the placenta is a prominence or tubercle with a vascular bundle bearing sporangia. In brown algae, it is a complex of cells under the sporangia, and in red algae, it is the widened base of the cystocarp.
What is the placenta that is destroyed by the ingrowing villi?
In the desmochorial placenta of many ruminants, the epithelium lining the depressions in the maternal mucosa is destroyed by enzymes of the epithelium of the ingrowing villi. In endotheliochorial placentas, which characterize all carnivores, not only the epithelium but also the connective tissue dissolves.
What hormones do the placenta produce?
It also acts as an endocrine gland, producing estrogen, progesterone, gonadotrophin, and serotonin, and works to prevent the mother's immune system from rejecting the fetus. Shortly after delivery of the fetus the placenta is forced out by contractions of the uterus.
How big is the placenta?
In a full-term fetus, it resembles a flat disk measuring 15 cm wide, 20 cm long, and about 3 cm thick; its weight is about 500 g.
What is the role of the placenta in the fetus?
The placenta acts as an interface between the mother and fetus, drawing nourishment and oxygen, which it supplies to the fetus, from the maternal circulation. In turn, the placenta receives the wastes of fetal metabolism and discharges them into the maternal circulation for disposal.
What is the epitheliochorial placenta?
i. Epitheliochorial Placenta: This type of placenta involves the contact of the chorionic epithelium with that of uterine epithelium and thus the term epitheliochorial. The epitheliochorial placenta involves six tissue barriers between the foetal and maternal circulation. It is the primitive type from which others have been derived and is seen in pig, sow, mare, horse, cattle etc. ii. Syndesmochorial Placenta: In the ruminant ungulates (cattle, sheep, deer, giraffe etc.), varying amounts of the uterine epithelium may be absent. As a result the chorion is brought into direct contact with the connective tissue of the uterus. Only five barriers therefore, lie between the two blood streams. This type of placenta is termed as syndesmochorial.
What is the difference between semi placenta and deciduous placenta?
As the chorionic villi do not fuse with the endometrium, such a placenta is also called semi placenta. ii. Deciduous Placenta or Placenta Vera: In cat, dog, primates, rodents etc., the degree of intimacy between the chorionic villi and the endometrium is greatly increased. The uterine wall gets eroded. The chorionic villi fuse with the eroded uterine mucosa. Such a placenta is termed as placenta vera (true placenta). At the time when parturition takes place the uterine wall does not remain intact. It tears away and extensive haemorrhage takes place at birth. Such a type of placenta is termed as deciduous placenta. This phenomena of shedding (tearing off) and replacement of maternal tissue is termed as decidua (meaning, to shed). Here the placenta is physiologically more efficient, where the mothers are protected enough to recover fully after child birth. iii. Contra-Deciduate Placenta: A somewhat modified type of deciduate placenta is seen in Parameles and Talpa (mole), where there is loss of both maternal tissue as well as foetal portion of placenta. Such a placenta is called contra-deciduate placenta.
What are the different types of placenta?
i. Diffused Placenta: In diffused placenta the villi are numerous and are scattered uniformly over the whole of chorion. It is seen in ungulates (pig, horse, mare etc.) and in cetacea. ii. Cotyledonary Place nta: In this type of placenta the villi become aggregated in special regions or patches to form small tufts. The rest part of the chorion surface remains smooth. It is seen in ruminant (cud-chewing) ungulates such as cattle, sheep, deer etc. In camel and giraffe an intermediate type of placenta is seen where the villi are scattered and are also arranged in cotyledons. iii. Zonary Placenta: In a zonary placenta the villi are confined to an annular or girdle-like zone on the chorion (chorion is more or less elliptical in shape). Such a placenta occurs in carnivores and may be of either incomplete zonary (e.g. raccoon) or complete zonary (e.g. dog, cat, seal etc.) type.
What is the meaning of the placenta?
Meaning of Placenta: The embryo, specially in eutherian mammals, becomes implanted to the ute-rine wall. The process of implantation in-volves tissue interaction and establishment of connection between the uterine wall and the extraembryonic membranes. The region of attachment between the embryo-nic tissue and the uterine wall is called the placenta and the process involved in im-plantation is called the placentation.The placenta is usually defined as an apposi-tion or fusion- between uterine and em-bryonic tissues for physiological exchange of materials. Classification of Placenta:
What is the name of the implantation of a mouse?
ii. Eccentric Implantation: In mouse, rat, beaver, squirrel etc., the blastocyst in its early stage comes to lie between the uterine epithelial folds or pocket (Fig. 5.53B), and this type of implantation is called eccentric implantation. The epithelial folds at a later stage, encloses the blastocyst almost completely. iii. Interstitial Implantation: In interstitial implantation the embryo burrows into the uterine mucosa below the epithelium and becomes surrounded completely by the endometrial tissue of the uterus (Fig. 5.53C). This type of implantation is seen in hedgehog, guinea-pig, some bats, chimpanzee, man etc.
What are the four types of classification of the placenta?
The types are: 1. Classification Based on the Degree of Intimacy 2. Classification Based on the Types of Implantation 3. Classification Based on the Distribution of Villi 4.
What is the difference between a monodiscoidal and a bidiscoidal placenta?
The mono-discoidal type with a single disc is seen in man, while the bi-discoidal type with two disc shaped villous areas is seen in monkeys.
What is the placenta of a camel?
In this type of placenta the villi become aggregated in special regions or patches to form small tufts. The rest part of the chorion surface remains smooth. It is seen in ruminant (cud-chewing) ungulates such as cattle, sheep, deer etc. In camel and giraffe an intermediate type of placenta is seen where the villi are scattered and are also arranged in cotyledons.
What is the contra deciduate placenta?
Contra-Deciduate Placenta: A somewhat modified type of deciduate placenta is seen in Parameles and Talpa (mole), where there is loss of both maternal tissue as well as foetal portion of placenta. Such a placenta is called contra-deciduate placenta. Type # 2.
What is the term for the chorionic villi fused with the eroded uterine mu?
The chorionic villi fuse with the eroded uterine mucosa. Such a placenta is termed as placenta vera (true placenta). At the time when parturition takes place the uterine wall does not remain intact. It tears away and extensive haemorrhage takes place at birth. Such a type of placenta is termed as deciduous placenta.
What happens to the villi at birth?
At the time of birth, when parturition takes place, the chorionic villi are simply withdrawn from the cavities of the uterine wall without causing any damage or bleeding. This type of placenta formation is seen in pig, cattle, horse etc., where the less hazardous birth process allows the females to resume full running speed soon after birth.
What is the term for the placenta that is tearing off?
Such a type of placenta is termed as deciduous placenta. ADVERTISEMENTS: This phenomena of shedding (tearing off) and replacement of maternal tissue is termed as decidua (meaning, to shed). Here the placenta is physiologically more efficient, where the mothers are protected enough to recover fully after child birth.
