Podcast
Questions and Answers
Which of the following extraembryonic membranes is not necessary in aquatic animals (fish and amphibians) for the development of the embryo?
Which of the following extraembryonic membranes is not necessary in aquatic animals (fish and amphibians) for the development of the embryo?
In addition to the yolk sac, which extraembryonic membranes are necessary for the development of the embryo in reptiles and birds?
In addition to the yolk sac, which extraembryonic membranes are necessary for the development of the embryo in reptiles and birds?
What remains the same in mammals as those that arose in reptiles and birds, even though mammals do not produce shelled eggs?
What remains the same in mammals as those that arose in reptiles and birds, even though mammals do not produce shelled eggs?
Which group of mammals represents the most ancient mammals that continue to lay shell eggs like their reptilian ancestors?
Which group of mammals represents the most ancient mammals that continue to lay shell eggs like their reptilian ancestors?
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What is the role of the chorion in mammalian development?
What is the role of the chorion in mammalian development?
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Which component plays a primary role in the interaction between the uterus and the blastula for attachment?
Which component plays a primary role in the interaction between the uterus and the blastula for attachment?
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What is the initial event marking the start of pregnancy in mammals?
What is the initial event marking the start of pregnancy in mammals?
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In which type of implantation does the blastocyst expand before implantation and remain in the center of the uterus?
In which type of implantation does the blastocyst expand before implantation and remain in the center of the uterus?
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What characterizes eccentric implantation in mammals?
What characterizes eccentric implantation in mammals?
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What is the process through which the conceptus gains control over corpus luteum function, uterine blood supply, and maternal physiology?
What is the process through which the conceptus gains control over corpus luteum function, uterine blood supply, and maternal physiology?
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How does embryo implantation occur in most mammals?
How does embryo implantation occur in most mammals?
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What is the role of integrins in embryo implantation?
What is the role of integrins in embryo implantation?
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What is a defining feature of interstitial implantation in mammals?
What is a defining feature of interstitial implantation in mammals?
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What is a key feature of human embryo implantation?
What is a key feature of human embryo implantation?
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What is unique about maternal recognition of pregnancy?
What is unique about maternal recognition of pregnancy?
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What is a distinguishing characteristic of mammals?
What is a distinguishing characteristic of mammals?
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Which group of mammals have a rudimentary connection between the embryo and the mother's uterus?
Which group of mammals have a rudimentary connection between the embryo and the mother's uterus?
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Where do newborn marsupial embryos develop further after birth?
Where do newborn marsupial embryos develop further after birth?
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What is the function of the allantoic placenta in placental mammals?
What is the function of the allantoic placenta in placental mammals?
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What role do the extraembryonic membranes play in prenatal survival of the mammalian embryo?
What role do the extraembryonic membranes play in prenatal survival of the mammalian embryo?
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What do the chorion, amnion, and allantois provide to mammals?
What do the chorion, amnion, and allantois provide to mammals?
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In what type of animals do the extraembryonic membranes form when the egg is incubated?
In what type of animals do the extraembryonic membranes form when the egg is incubated?
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What is the name of the trilaminate membrane formed in birds from the expanded yolk sac, amnion, and allantois?
What is the name of the trilaminate membrane formed in birds from the expanded yolk sac, amnion, and allantois?
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Which group of mammals has a more elaborate and efficient connection between the embryo and the mother's uterus through an allantoic placenta?
Which group of mammals has a more elaborate and efficient connection between the embryo and the mother's uterus through an allantoic placenta?
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What do placental mammals provide to their embryos through the allantoic placenta?
What do placental mammals provide to their embryos through the allantoic placenta?
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Which group of mammals includes domestic mammals and humans?
Which group of mammals includes domestic mammals and humans?
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What contributes to the development of placental circulation in mammals?
What contributes to the development of placental circulation in mammals?
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In which type of mammals does the blastocyst enter a dormant status named diapause?
In which type of mammals does the blastocyst enter a dormant status named diapause?
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What is the adaptive process in mammals that ensures optimal survival conditions to the offspring?
What is the adaptive process in mammals that ensures optimal survival conditions to the offspring?
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In which type of mammals is facultative diapause regulated through lactation?
In which type of mammals is facultative diapause regulated through lactation?
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Which type of delayed implantation allows mammals to program the birth of their young under favorable environmental conditions?
Which type of delayed implantation allows mammals to program the birth of their young under favorable environmental conditions?
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What are the maternal uterine glands called that provide the embryo with energy and biochemical building blocks before implantation?
What are the maternal uterine glands called that provide the embryo with energy and biochemical building blocks before implantation?
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Which process rapidly becomes insufficient as the embryo grows, leading to the development of the placenta?
Which process rapidly becomes insufficient as the embryo grows, leading to the development of the placenta?
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Which type of placentas have developed specialized regions called placental areolae for ingestion of uterine secretions and cell debris?
Which type of placentas have developed specialized regions called placental areolae for ingestion of uterine secretions and cell debris?
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In which type of mammals do species with highly efficient placentas have minimal histotrophic uptake throughout most of gestation?
In which type of mammals do species with highly efficient placentas have minimal histotrophic uptake throughout most of gestation?
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What is the name for the tissue created by the transformation of uterine stromal and endothelial cells during implantation?
What is the name for the tissue created by the transformation of uterine stromal and endothelial cells during implantation?
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What is the outer layer of the invasive trophoblast that forms an irregular invasive tissue called?
What is the outer layer of the invasive trophoblast that forms an irregular invasive tissue called?
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In which type of animals does attachment and implantation occur within a few days after the blastocyst reaches the uterus?
In which type of animals does attachment and implantation occur within a few days after the blastocyst reaches the uterus?
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What is the role of the allantois in the development of mammals?
What is the role of the allantois in the development of mammals?
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What characteristic distinguishes the placenta in domestic animals?
What characteristic distinguishes the placenta in domestic animals?
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In which type of mammals do species with highly efficient placentas have minimal histotrophic uptake throughout most of gestation?
In which type of mammals do species with highly efficient placentas have minimal histotrophic uptake throughout most of gestation?
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What is the primary role of the amnion in reptiles, birds, and mammals?
What is the primary role of the amnion in reptiles, birds, and mammals?
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What is the primary component in the interaction between the uterus and the blastula for attachment in mammals?
What is the primary component in the interaction between the uterus and the blastula for attachment in mammals?
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Which type of implantation involves the blastocyst expanding before implantation and remaining in the center of the uterus, common in domestic animals?
Which type of implantation involves the blastocyst expanding before implantation and remaining in the center of the uterus, common in domestic animals?
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What is the function of the chorion in mammalian development?
What is the function of the chorion in mammalian development?
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In which type of mammals does the blastocyst implant between the uterine glands, as found in marsupials?
In which type of mammals does the blastocyst implant between the uterine glands, as found in marsupials?
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What is the adaptive process in mammals that ensures optimal survival conditions to the offspring?
What is the adaptive process in mammals that ensures optimal survival conditions to the offspring?
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What characterizes eccentric implantation in mammals?
What characterizes eccentric implantation in mammals?
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What is a key feature of human embryo implantation?
What is a key feature of human embryo implantation?
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What are the maternal uterine glands called that provide the embryo with energy and biochemical building blocks before implantation?
What are the maternal uterine glands called that provide the embryo with energy and biochemical building blocks before implantation?
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What is unique about maternal recognition of pregnancy?
What is unique about maternal recognition of pregnancy?
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What contributes to the development of placental circulation in mammals?
What contributes to the development of placental circulation in mammals?
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In which type of animals does attachment and implantation occur within a few days after the blastocyst reaches the uterus?
In which type of animals does attachment and implantation occur within a few days after the blastocyst reaches the uterus?
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What remains the same in mammals as those that arose in reptiles and birds, even though mammals do not produce shelled eggs?
What remains the same in mammals as those that arose in reptiles and birds, even though mammals do not produce shelled eggs?
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What is the role of the allantoic placenta in placental mammals?
What is the role of the allantoic placenta in placental mammals?
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Which extraembryonic membranes are adaptations to terrestrial life in mammals?
Which extraembryonic membranes are adaptations to terrestrial life in mammals?
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Where do newborn marsupial embryos develop further after birth?
Where do newborn marsupial embryos develop further after birth?
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What do the chorion, amnion, and allantois provide to mammals?
What do the chorion, amnion, and allantois provide to mammals?
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What characterizes eccentric implantation in mammals?
What characterizes eccentric implantation in mammals?
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What remains the same in mammals as those that arose in reptiles and birds, even though mammals do not produce shelled eggs?
What remains the same in mammals as those that arose in reptiles and birds, even though mammals do not produce shelled eggs?
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Which type of delayed implantation allows mammals to program the birth of their young under favorable environmental conditions?
Which type of delayed implantation allows mammals to program the birth of their young under favorable environmental conditions?
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What contributes to the development of placental circulation in mammals?
What contributes to the development of placental circulation in mammals?
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What is a defining feature of interstitial implantation in mammals?
What is a defining feature of interstitial implantation in mammals?
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In which type of animals do the extraembryonic membranes form when the egg is incubated?
In which type of animals do the extraembryonic membranes form when the egg is incubated?
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What is a distinguishing characteristic of placental mammals?
What is a distinguishing characteristic of placental mammals?
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What contributes to the prenatal survival of the mammalian embryo?
What contributes to the prenatal survival of the mammalian embryo?
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What is the process of implantation often called?
What is the process of implantation often called?
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Which type of implantation allows the blastocyst to expand before implantation and remain in the center of the uterus?
Which type of implantation allows the blastocyst to expand before implantation and remain in the center of the uterus?
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What is the name of the tissue formed by the outer layer of the invasive trophoblast in mammals?
What is the name of the tissue formed by the outer layer of the invasive trophoblast in mammals?
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What is the function of the maternal uterine glands before implantation?
What is the function of the maternal uterine glands before implantation?
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In which type of mammals does facultative diapause occur?
In which type of mammals does facultative diapause occur?
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Which type of mammals presents delayed implantation due to embryonic diapause?
Which type of mammals presents delayed implantation due to embryonic diapause?
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What replaces histiotrophe as the embryo grows in mammals?
What replaces histiotrophe as the embryo grows in mammals?
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'Haemotrophe' becomes the primary source of nutrients for the embryo in species with a highly efficient placenta. Which group of mammals have minimal histotrophic uptake throughout most of gestation?
'Haemotrophe' becomes the primary source of nutrients for the embryo in species with a highly efficient placenta. Which group of mammals have minimal histotrophic uptake throughout most of gestation?
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What is a distinguishing characteristic of delayed implantation in some mammalian species?
What is a distinguishing characteristic of delayed implantation in some mammalian species?
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What is the primary function of the placenta in all species?
What is the primary function of the placenta in all species?
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What is the degree of trophoblast invasion variable between, leading to varying numbers of layers of the placental barrier in different species?
What is the degree of trophoblast invasion variable between, leading to varying numbers of layers of the placental barrier in different species?
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What is the role of the close approximation of maternal and foetal vascular systems within the placenta?
What is the role of the close approximation of maternal and foetal vascular systems within the placenta?
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What is important to recognize about the placenta's function?
What is important to recognize about the placenta's function?
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What is the primary function of the placental barrier?
What is the primary function of the placental barrier?
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What is the primary role of the allantois in placental mammals?
What is the primary role of the allantois in placental mammals?
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Which type of placentas have developed specialized regions for ingestion of uterine secretions and cell debris?
Which type of placentas have developed specialized regions for ingestion of uterine secretions and cell debris?
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What contributes to the development of placental circulation in mammals?
What contributes to the development of placental circulation in mammals?
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Which extraembryonic membrane is an important endocrine organ that produces various hormones?
Which extraembryonic membrane is an important endocrine organ that produces various hormones?
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In which type of mammals is there substantial transfer of immunoglobulin G prior to birth?
In which type of mammals is there substantial transfer of immunoglobulin G prior to birth?
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Which component plays a primary role in the interaction between the uterus and the blastula for attachment?
Which component plays a primary role in the interaction between the uterus and the blastula for attachment?
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What is the name for the tissue formed by the outer layer of the invasive trophoblast in mammals?
What is the name for the tissue formed by the outer layer of the invasive trophoblast in mammals?
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What is a distinguishing characteristic of mammals with delayed implantation due to embryonic diapause?
What is a distinguishing characteristic of mammals with delayed implantation due to embryonic diapause?
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What is unique about maternal recognition of pregnancy?
What is unique about maternal recognition of pregnancy?
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What is the primary role of the amnion in reptiles, birds, and mammals?
What is the primary role of the amnion in reptiles, birds, and mammals?
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What is the principal source of equine chorionic gonadotrophin (eCG) in horses?
What is the principal source of equine chorionic gonadotrophin (eCG) in horses?
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What are the polygonal structures, 1-2 mm in size, found on the chorionic surface of the equine placenta?
What are the polygonal structures, 1-2 mm in size, found on the chorionic surface of the equine placenta?
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What is the name for the brownish masses of cellular debris surrounded by mucoproteins and minerals found in the allantoic cavity of horses?
What is the name for the brownish masses of cellular debris surrounded by mucoproteins and minerals found in the allantoic cavity of horses?
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What do uterine glands in horses empty into, providing copious secretions that are absorbed by inter-microcotyledonary areas of the chorion?
What do uterine glands in horses empty into, providing copious secretions that are absorbed by inter-microcotyledonary areas of the chorion?
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What is the name for the epithelial elevations on the amniotic wall that can be present near the umbilical cord in horses?
What is the name for the epithelial elevations on the amniotic wall that can be present near the umbilical cord in horses?
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In horses, what is the average time needed for placental expulsion after birth?
In horses, what is the average time needed for placental expulsion after birth?
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What is one of the most common peripartum problems in mares, with an incidence in the range of 2% to 10%?
What is one of the most common peripartum problems in mares, with an incidence in the range of 2% to 10%?
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In horses, what is the name for the mass of cellular debris likely originating from the foetal hindgut found floating or attached to the wall of the allantoic cavity?
In horses, what is the name for the mass of cellular debris likely originating from the foetal hindgut found floating or attached to the wall of the allantoic cavity?
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What marks the start of pregnancy in horses?
What marks the start of pregnancy in horses?
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Which structure quickly disappears in horses after birth, allowing foals to be usually born surrounded by it and requiring their own effort to break it?
Which structure quickly disappears in horses after birth, allowing foals to be usually born surrounded by it and requiring their own effort to break it?
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What ensures there is no significant loss of maternal tissue after birth in horses' placentation?
What ensures there is no significant loss of maternal tissue after birth in horses' placentation?
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Which type of placentation is characterized by a complete or incomplete band of tissue surrounding the foetus?
Which type of placentation is characterized by a complete or incomplete band of tissue surrounding the foetus?
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In which type of placentation are chorionic villi restricted to multiple areas of attachment, forming cotyledons and caruncles in ruminants?
In which type of placentation are chorionic villi restricted to multiple areas of attachment, forming cotyledons and caruncles in ruminants?
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Which type of placenta is the most invasive, where the trophoblast erodes the endometrium and comes in direct contact with maternal blood?
Which type of placenta is the most invasive, where the trophoblast erodes the endometrium and comes in direct contact with maternal blood?
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Which type of embryo implantation involves the blastocyst expanding before implantation and remaining in the center of the uterus, common in domestic animals?
Which type of embryo implantation involves the blastocyst expanding before implantation and remaining in the center of the uterus, common in domestic animals?
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What term is used for the tissue formed by the transformation of uterine stromal and endothelial cells during implantation?
What term is used for the tissue formed by the transformation of uterine stromal and endothelial cells during implantation?
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In which placentation type is almost the entire surface of the allantochorion involved in the formation of the placenta, found in horses and pigs?
In which placentation type is almost the entire surface of the allantochorion involved in the formation of the placenta, found in horses and pigs?
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Which type of placentation involves chorionic villi eroding and fusing with the uterine mucosa, forming decidua?
Which type of placentation involves chorionic villi eroding and fusing with the uterine mucosa, forming decidua?
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What type of placentation is characterized by a single area of placenta being formed and being discoid in shape, found in primates and rodents?
What type of placentation is characterized by a single area of placenta being formed and being discoid in shape, found in primates and rodents?
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Which type of placentation involves chorionic villi attaching to the maternal uterine epithelium, with no maternal invasion?
Which type of placentation involves chorionic villi attaching to the maternal uterine epithelium, with no maternal invasion?
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What is an example of a classification based on placental shape?
What is an example of a classification based on placental shape?
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What is a modification of epitheliochorial placenta, where trophoblast cells migrate and fuse with the maternal epithelium?
What is a modification of epitheliochorial placenta, where trophoblast cells migrate and fuse with the maternal epithelium?
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What is the primary function of the placenta in all species?
What is the primary function of the placenta in all species?
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What constitutes the placental barrier?
What constitutes the placental barrier?
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What is the name for the tissue created by the transformation of uterine stromal and endothelial cells during implantation?
What is the name for the tissue created by the transformation of uterine stromal and endothelial cells during implantation?
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What role do the extraembryonic membranes play in prenatal survival of the mammalian embryo?
What role do the extraembryonic membranes play in prenatal survival of the mammalian embryo?
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What is the average time needed for placental expulsion after birth in horses?
What is the average time needed for placental expulsion after birth in horses?
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Which structure provides temporary hormone production and secretes eCG during early pregnancy in horses?
Which structure provides temporary hormone production and secretes eCG during early pregnancy in horses?
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What marks the start of pregnancy in horses?
What marks the start of pregnancy in horses?
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What is the name for the mass of cellular debris likely originating from the foetal hindgut found floating or attached to the wall of the allantoic cavity in horses?
What is the name for the mass of cellular debris likely originating from the foetal hindgut found floating or attached to the wall of the allantoic cavity in horses?
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What contributes to the development of placental circulation in horses?
What contributes to the development of placental circulation in horses?
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What ensures there is no significant loss of maternal tissue after birth in horses' placentation?
What ensures there is no significant loss of maternal tissue after birth in horses' placentation?
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Which process rapidly becomes insufficient as the embryo grows, leading to the development of the placenta in horses?
Which process rapidly becomes insufficient as the embryo grows, leading to the development of the placenta in horses?
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What is unique about maternal recognition of pregnancy in horses?
What is unique about maternal recognition of pregnancy in horses?
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In horses, what is the primary role of the amnion?
In horses, what is the primary role of the amnion?
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Which type of placentation is characterized by the chorionic villi being restricted to multiple areas of attachment, forming cotyledons and caruncles in ruminants?
Which type of placentation is characterized by the chorionic villi being restricted to multiple areas of attachment, forming cotyledons and caruncles in ruminants?
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In which type of mammals is the entire surface of the allantochorion involved in the formation of the placenta?
In which type of mammals is the entire surface of the allantochorion involved in the formation of the placenta?
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Which type of placentation forms a complete or incomplete band of tissue surrounding the foetus, seen in carnivores and some other animals?
Which type of placentation forms a complete or incomplete band of tissue surrounding the foetus, seen in carnivores and some other animals?
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What is the most invasive placenta, where the trophoblast erodes the endometrium and comes in direct contact with maternal blood?
What is the most invasive placenta, where the trophoblast erodes the endometrium and comes in direct contact with maternal blood?
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Which type of placentation is found in horses and pigs, involving almost the entire surface of the allantochorion in the formation of the placenta?
Which type of placentation is found in horses and pigs, involving almost the entire surface of the allantochorion in the formation of the placenta?
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Which type of placentation is characterized by a single area of placenta being formed and being discoid in shape, found in primates and rodents?
Which type of placentation is characterized by a single area of placenta being formed and being discoid in shape, found in primates and rodents?
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Which type of placentation is characterized by chorionic villi eroding and fusing with the uterine mucosa, forming decidua?
Which type of placentation is characterized by chorionic villi eroding and fusing with the uterine mucosa, forming decidua?
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What type of placentation involves the chorion villi attaching to the maternal uterine epithelium, with no maternal invasion?
What type of placentation involves the chorion villi attaching to the maternal uterine epithelium, with no maternal invasion?
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What is the principal source of equine chorionic gonadotrophin (eCG) in horses?
What is the principal source of equine chorionic gonadotrophin (eCG) in horses?
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What are the brownish masses of cellular debris surrounded by mucoproteins and minerals found in the allantoic cavity of horses?
What are the brownish masses of cellular debris surrounded by mucoproteins and minerals found in the allantoic cavity of horses?
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What is the name for the epithelial elevations on the amniotic wall that can be present near the umbilical cord in horses?
What is the name for the epithelial elevations on the amniotic wall that can be present near the umbilical cord in horses?
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What do uterine glands, present in the maternal stroma between adjacent microcotyledons, empty their secretions into?
What do uterine glands, present in the maternal stroma between adjacent microcotyledons, empty their secretions into?
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Where do newborn foals typically develop further after birth?
Where do newborn foals typically develop further after birth?
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What is a common peripartum problem in mares, with an incidence in the range of 2% to 10%?
What is a common peripartum problem in mares, with an incidence in the range of 2% to 10%?
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What is the classification of equine placenta based on its structure?
What is the classification of equine placenta based on its structure?
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What do the areolas in horses' placenta oppose to, receiving secretions from uterine glands?
What do the areolas in horses' placenta oppose to, receiving secretions from uterine glands?
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What is the role of the amniotic raphe in horses' placentation?
What is the role of the amniotic raphe in horses' placentation?
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What happens to the amnion after birth in horses?
What happens to the amnion after birth in horses?
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What marks the start of pregnancy in horses?
What marks the start of pregnancy in horses?
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What is the primary method of energy transfer from the placenta to the fetus?
What is the primary method of energy transfer from the placenta to the fetus?
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Which gas readily diffuses from maternal to fetal blood due to a higher partial pressure in maternal blood?
Which gas readily diffuses from maternal to fetal blood due to a higher partial pressure in maternal blood?
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Which hormone is produced by the placenta and is an important endocrine hormone in mammals?
Which hormone is produced by the placenta and is an important endocrine hormone in mammals?
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What is the primary function of the placenta in protecting the fetus?
What is the primary function of the placenta in protecting the fetus?
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In which type of placentas do the allantois fuse with the chorion to form the final placenta in eutherian mammals?
In which type of placentas do the allantois fuse with the chorion to form the final placenta in eutherian mammals?
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What is actively transported to the fetus with higher concentrations in fetal blood?
What is actively transported to the fetus with higher concentrations in fetal blood?
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What helps remove waste products such as urea, creatinine, uric acid, and bilirubin from fetal blood?
What helps remove waste products such as urea, creatinine, uric acid, and bilirubin from fetal blood?
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What is an important characteristic of gas transport across the placental barrier?
What is an important characteristic of gas transport across the placental barrier?
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What is a characteristic of the transfer of immunoglobulins across the placenta in rodents and primates?
What is a characteristic of the transfer of immunoglobulins across the placenta in rodents and primates?
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What is the primary role of the amnion in reptiles, birds, and mammals?
What is the primary role of the amnion in reptiles, birds, and mammals?
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What is unique about the transfer of immunoglobulins across the placenta in domestic animals?
What is unique about the transfer of immunoglobulins across the placenta in domestic animals?
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What is the primary reason why twinning is considered undesirable in cows?
What is the primary reason why twinning is considered undesirable in cows?
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What is the most common outcome when female calves are born co-twin to a male in cattle?
What is the most common outcome when female calves are born co-twin to a male in cattle?
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In bovine twins, what allows hormones from the male to affect female development and leads to the mixing of haemopoietic precursor cells?
In bovine twins, what allows hormones from the male to affect female development and leads to the mixing of haemopoietic precursor cells?
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Which species is freemartin syndrome rarely present in, despite frequent occurrences of double or triple births?
Which species is freemartin syndrome rarely present in, despite frequent occurrences of double or triple births?
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What is the primary type of placenta found in pigs?
What is the primary type of placenta found in pigs?
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What is the primary type of placenta found in dogs and cats?
What is the primary type of placenta found in dogs and cats?
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What is the characteristic of the uterine mucosa in pigs that maximizes placental exchange area?
What is the characteristic of the uterine mucosa in pigs that maximizes placental exchange area?
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What characterizes the initial structure of the canine placenta?
What characterizes the initial structure of the canine placenta?
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What characterizes the allantoic vessels in the pig's placenta?
What characterizes the allantoic vessels in the pig's placenta?
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What is the characteristic of the amnion in carnivores?
What is the characteristic of the amnion in carnivores?
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What characterizes the umbilical cord in carnivores?
What characterizes the umbilical cord in carnivores?
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Which term describes the type of placentation in horses and pigs, involving almost the entire surface of the allantochorion?
Which term describes the type of placentation in horses and pigs, involving almost the entire surface of the allantochorion?
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What marks a distinguishing feature of the equine placenta?
What marks a distinguishing feature of the equine placenta?
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What characterizes the transfer of immunoglobulins across the placenta in rodents and primates?
What characterizes the transfer of immunoglobulins across the placenta in rodents and primates?
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What contributes to prenatal survival of mammalian embryos via the placenta?
What contributes to prenatal survival of mammalian embryos via the placenta?
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What is a defining feature of mammals with delayed implantation due to embryonic diapause?
What is a defining feature of mammals with delayed implantation due to embryonic diapause?
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In ruminants, what is the structure referred to as synepitheliochorial due to modified uterine epithelium?
In ruminants, what is the structure referred to as synepitheliochorial due to modified uterine epithelium?
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What is the term for the small placental areas in the cotyledonary placenta of ruminants?
What is the term for the small placental areas in the cotyledonary placenta of ruminants?
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What is the name of the oval or round thickenings in the uterine mucosa in ruminants?
What is the name of the oval or round thickenings in the uterine mucosa in ruminants?
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What characterizes implantation in pigs, involving a lengthy pre-attachment period and remodeling of the embryonic vesicle?
What characterizes implantation in pigs, involving a lengthy pre-attachment period and remodeling of the embryonic vesicle?
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How many piglets are typically found in a litter size of pigs?
How many piglets are typically found in a litter size of pigs?
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What characterizes the delivery of the placenta in ruminants within 12 hours of birth?
What characterizes the delivery of the placenta in ruminants within 12 hours of birth?
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In pigs, which process occurs to form a filamentous sac during implantation?
In pigs, which process occurs to form a filamentous sac during implantation?
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What characterizes implantation in pigs, involving a lengthy pre-attachment period and remodeling of the embryonic vesicle?
What characterizes implantation in pigs, involving a lengthy pre-attachment period and remodeling of the embryonic vesicle?
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What is the term for the abnormal development of the reproductive system in female calves born co-twin to a male in cattle?
What is the term for the abnormal development of the reproductive system in female calves born co-twin to a male in cattle?
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What is the most common form of intersexuality in cattle?
What is the most common form of intersexuality in cattle?
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In which species is freemartin syndrome rarely present, even in cases of double or triple births?
In which species is freemartin syndrome rarely present, even in cases of double or triple births?
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What is the main reason why twinning is considered undesirable in cattle?
What is the main reason why twinning is considered undesirable in cattle?
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What type of placenta is characteristic of ruminants?
What type of placenta is characteristic of ruminants?
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What structures form the placentome in ruminants?
What structures form the placentome in ruminants?
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What is the term for the delivery of the placenta within 12 hours of birth in ruminants?
What is the term for the delivery of the placenta within 12 hours of birth in ruminants?
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What characterizes implantation in pigs?
What characterizes implantation in pigs?
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What is the litter size range for pigs?
What is the litter size range for pigs?
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What is the main source of nutrients for the embryo in species with a highly efficient placenta?
What is the main source of nutrients for the embryo in species with a highly efficient placenta?
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What type of placentation is found in horses and pigs?
What type of placentation is found in horses and pigs?
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In which group of mammals does facultative diapause occur?
In which group of mammals does facultative diapause occur?
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What is the term for the small placental areas in the cotyledonary placenta of ruminants?
What is the term for the small placental areas in the cotyledonary placenta of ruminants?
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Study Notes
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Mammals are a group of animals with backbones, hair or fur, warm-blooded, and feed their young with milk.
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Mammals can be divided into three groups based on how their offspring develop: monotremes, marsupials, and placental mammals.
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Marsupials have a rudimentary connection between the embryo and the mother's uterus through a yolk placenta.
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Newborn marsupial embryos are born very immature and develop further in a pouch, where they find milk to complete their development.
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Placental mammals, such as domestic mammals and humans, have a more elaborate and efficient connection between the embryo and the mother's uterus through an allantoic placenta.
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The allantoic placenta provides the embryo with nutrition, respiration, excretion, and endocrine function, allowing for complete embryonic development.
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Extraembryonic membranes are essential for the prenatal survival of the embryo and develop from the same germ layers as the embryo.
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Extraembryonic membranes include the chorion, amnion, yolk sac, and allantois.
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In mammals, the allantoic placenta gives rise to the placental circulation.
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The chorion, amnion, and allantois are adaptations to terrestrial life, providing protection, interchanging gases and nutrients, and handling excretion.
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In birds, the extraembryonic membranes form when the egg is incubated, and the yolk sac, amnion, and allantois expand, attaching to different layers and forming a trilaminate membrane called the allantochorion.
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Mammals are a group of animals with backbones, hair or fur, warm-blooded, and feed their young with milk.
-
Mammals can be divided into three groups based on how their offspring develop: monotremes, marsupials, and placental mammals.
-
Marsupials have a rudimentary connection between the embryo and the mother's uterus through a yolk placenta.
-
Newborn marsupial embryos are born very immature and develop further in a pouch, where they find milk to complete their development.
-
Placental mammals, such as domestic mammals and humans, have a more elaborate and efficient connection between the embryo and the mother's uterus through an allantoic placenta.
-
The allantoic placenta provides the embryo with nutrition, respiration, excretion, and endocrine function, allowing for complete embryonic development.
-
Extraembryonic membranes are essential for the prenatal survival of the embryo and develop from the same germ layers as the embryo.
-
Extraembryonic membranes include the chorion, amnion, yolk sac, and allantois.
-
In mammals, the allantoic placenta gives rise to the placental circulation.
-
The chorion, amnion, and allantois are adaptations to terrestrial life, providing protection, interchanging gases and nutrients, and handling excretion.
-
In birds, the extraembryonic membranes form when the egg is incubated, and the yolk sac, amnion, and allantois expand, attaching to different layers and forming a trilaminate membrane called the allantochorion.
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The placental barrier is a selective membrane that allows the transfer of nutrients, gases, waste products, antibodies, infectious agents, and hormones between the mother and fetus.
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Cells do not normally cross the placental barrier, while gases do so easily due to their small molecule size.
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Nutrient transport: The placenta provides energy to the fetus primarily through the transfer of glucose by facilitated diffusion.foetus receives large amounts of intact glucose but a significant amount is oxidized within the placenta to lactate. Amino acids are also actively transported to the fetus, with higher concentrations in fetal blood.
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Gas transport: Oxygen readily diffuses from maternal to fetal blood due to a higher partial pressure in maternal blood. Carbon dioxide, which is produced abundantly by the fetus, diffuses from fetal blood into maternal blood.
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Excretory function: The placental exchange processes help remove waste products such as urea, creatinine, uric acid, and bilirubin from fetal blood.
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Protective function: The placenta serves as a protective barrier against infectious agents and drugs, but the ability of these substances to cross the placental barrier depends on their size and the specific characteristics of the placenta.
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Immunoglobulin transfer: There are marked differences between species in the transfer of immunoglobulins across the placenta. In primates and rodents, there is substantial transfer of immunoglobulin G prior to birth, while in domestic animals, the neonate is essentially devoid of circulating antibodies until it absorbs them from colostrum.
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Hormone production: The placenta is an important endocrine organ that produces various hormones, including steroid hormones like estrogens and progesterone, and protein hormones such as chorionic gonadotrophins.
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Placental types: There are different types of placentas based on the placental membranes. In choriovitelline placentas, the yolk sac fuses broadly with the chorion to form a choriovitelline membrane, which is supported by vitelline blood vessels. In chorioallantoic placentas, the allantois fuses with the chorion, with the corionic villi of the membrane forming the fetal tissues that develop into the final placenta in eutherian mammals.
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Chorioallantoic placenta: Developed with the support of the chorioallantoic membrane and allantoic vessels.
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Non-deciduate placenta: Found in most domestic animals with simple chorionic villi; chorion does not fuse with the endometrium.
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Deciduate placenta: In species with an invasive chorion, chorionic villi erode and fuse with the uterine mucosa, forming decidua.
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Epitheliochorial placenta: Chorion villi attach to the maternal uterine epithelium, with no maternal invasion.
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Synepitheliochorial placenta: A modification of epitheliochorial placenta, where trophoblast cells migrate and fuse with the maternal epithelium.
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Endotheliochorial placenta: The chorion erodes the uterine epithelium and invades the maternal connective tissue.
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Haemochorial placenta: The most invasive placenta, where the trophoblast erodes the endometrium and comes in direct contact with maternal blood.
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Classification based on placenta shape:
- Diffuse placenta: Almost the entire surface of the allantochorion is involved in the formation of the placenta, found in horses and pigs.
- Cotyledonary or multiple placentation: Chorionic villi are restricted to multiple areas of attachment, forming cotyledons and caruncles in ruminants.
- Zonary placenta: A complete or incomplete band of tissue surrounding the foetus, seen in carnivores and some other animals.
- Discoid placenta: A single area of placenta is formed and is discoid in shape, found in primates and rodents.
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Chorioallantoic placenta: Developed with the support of the chorioallantoic membrane and allantoic vessels.
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Non-deciduate placenta: Found in most domestic animals with simple chorionic villi; chorion does not fuse with the endometrium.
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Deciduate placenta: In species with an invasive chorion, chorionic villi erode and fuse with the uterine mucosa, forming decidua.
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Epitheliochorial placenta: Chorion villi attach to the maternal uterine epithelium, with no maternal invasion.
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Synepitheliochorial placenta: A modification of epitheliochorial placenta, where trophoblast cells migrate and fuse with the maternal epithelium.
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Endotheliochorial placenta: The chorion erodes the uterine epithelium and invades the maternal connective tissue.
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Haemochorial placenta: The most invasive placenta, where the trophoblast erodes the endometrium and comes in direct contact with maternal blood.
-
Classification based on placenta shape:
- Diffuse placenta: Almost the entire surface of the allantochorion is involved in the formation of the placenta, found in horses and pigs.
- Cotyledonary or multiple placentation: Chorionic villi are restricted to multiple areas of attachment, forming cotyledons and caruncles in ruminants.
- Zonary placenta: A complete or incomplete band of tissue surrounding the foetus, seen in carnivores and some other animals.
- Discoid placenta: A single area of placenta is formed and is discoid in shape, found in primates and rodents.
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The placental barrier is a selective membrane that allows the transfer of nutrients, gases, waste products, antibodies, infectious agents, and hormones between the mother and fetus.
-
Cells do not normally cross the placental barrier, while gases do so easily due to their small molecule size.
-
Nutrient transport: The placenta provides energy to the fetus primarily through the transfer of glucose by facilitated diffusion.foetus receives large amounts of intact glucose but a significant amount is oxidized within the placenta to lactate. Amino acids are also actively transported to the fetus, with higher concentrations in fetal blood.
-
Gas transport: Oxygen readily diffuses from maternal to fetal blood due to a higher partial pressure in maternal blood. Carbon dioxide, which is produced abundantly by the fetus, diffuses from fetal blood into maternal blood.
-
Excretory function: The placental exchange processes help remove waste products such as urea, creatinine, uric acid, and bilirubin from fetal blood.
-
Protective function: The placenta serves as a protective barrier against infectious agents and drugs, but the ability of these substances to cross the placental barrier depends on their size and the specific characteristics of the placenta.
-
Immunoglobulin transfer: There are marked differences between species in the transfer of immunoglobulins across the placenta. In primates and rodents, there is substantial transfer of immunoglobulin G prior to birth, while in domestic animals, the neonate is essentially devoid of circulating antibodies until it absorbs them from colostrum.
-
Hormone production: The placenta is an important endocrine organ that produces various hormones, including steroid hormones like estrogens and progesterone, and protein hormones such as chorionic gonadotrophins.
-
Placental types: There are different types of placentas based on the placental membranes. In choriovitelline placentas, the yolk sac fuses broadly with the chorion to form a choriovitelline membrane, which is supported by vitelline blood vessels. In chorioallantoic placentas, the allantois fuses with the chorion, with the corionic villi of the membrane forming the fetal tissues that develop into the final placenta in eutherian mammals.
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In pigs, the chorioamniotic raphe or mesoamnion persists throughout gestation, with the allantois expanding ventrally to quickly form the chorioallantoic placenta while the yolk sac shrinks towards the umbilicus.
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The pig's placenta is non-invasive, epitheliochorial, and diffuse with atrophy at the peripheral tips. The allantois vessels do not expand to the tips of the chorionic sac, resulting in avascular and necrotic parts.
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The uterine mucosa in pigs is provided with transversal folds, maximizing the placental exchange area with macroscopic circular folds in the chorion. The chorion has a conspicuous presence of circular areolas where uterine glands open.
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Carnivores, such as dogs and cats, have a zonary placenta that forms a band around the foetus. They undergo efficient trans-uterine migration before implantation and typically have 3-8 foetuses.
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The amnion in carnivores separates rapidly from the chorion, and the allantois expands dorsally to interpose itself between the amnion and the chorion. The placenta is endotheliochorial, with the foetal chorionic epithelium in contact with the endothelial cells of maternal vessels.
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The initial structure of the canine placenta is in the form of straight folds, referred to as lamellae, which soon become branched and twisted, resulting in the formation of the labyrinthine placenta. The placenta is deciduate, and the marginal haematoma is a band of maternal haemorrhage at the margins of the zonary placenta, with distinctly green colouration in dogs.
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The carnivore placenta is described as having an allantoic duct and four vessels (two umbilical arteries and two umbilical veins), but only the left umbilical vein enters the embryo's body. The umbilical cord is short and has few twists.
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'Freemartin' is a phenomenon where a female twin is born with male hormones affecting her reproductive system due to placental circulations anastomoses.
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Implantation in ruminants occurs during the peri-implantation period, involving reciprocal interactions between the elongating conceptus and endometrium.
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Ruminants have an epitheliochorial placenta, but its structure is referred to as synepitheliochorial due to modified uterine epithelium.
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Ruminant placenta is cotyledonary, with numerous smaller placental areas called placentomes.
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Each placentome consists of a cotyledon (foetal part) and a caruncle (maternal side).
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Cotyledons are made of chorion frondosum, while caruncles are oval or round thickenings in the uterine mucosa.
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The placenta is delivered within 12 hours of birth, without significant loss of maternal tissue, making ruminant placentation non-deciduate.
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In pigs, implantation is characterized by a lengthy pre-attachment period and remodeling of the embryonic vesicle to form a filamentous sac.
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Pigs are polytocous animals giving birth to multiple offspring at the same time, with a litter size between 6 and 12 piglets.
-
'Freemartin' is a phenomenon where a female twin is born with male hormones affecting her reproductive system due to placental circulations anastomoses.
-
Implantation in ruminants occurs during the peri-implantation period, involving reciprocal interactions between the elongating conceptus and endometrium.
-
Ruminants have an epitheliochorial placenta, but its structure is referred to as synepitheliochorial due to modified uterine epithelium.
-
Ruminant placenta is cotyledonary, with numerous smaller placental areas called placentomes.
-
Each placentome consists of a cotyledon (foetal part) and a caruncle (maternal side).
-
Cotyledons are made of chorion frondosum, while caruncles are oval or round thickenings in the uterine mucosa.
-
The placenta is delivered within 12 hours of birth, without significant loss of maternal tissue, making ruminant placentation non-deciduate.
-
In pigs, implantation is characterized by a lengthy pre-attachment period and remodeling of the embryonic vesicle to form a filamentous sac.
-
Pigs are polytocous animals giving birth to multiple offspring at the same time, with a litter size between 6 and 12 piglets.
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Description
Explore the development and adaptive modifications of extraembryonic membranes in mammals, including the yolk sac, amnion, and allantois. Learn how these membranes continue to form despite the absence of yolk accumulation and the intrauterine mode of development.
