How does the body create it? How is it structured? How does it keep the baby alive? How does it attach/detach from the uterus?
In: 2
Formation
Formed partly from stem cells from the same group that goes onto form the fetus, and partly from the endometrium, the lining of mum’s uterus. They grow blood vessels that line up very close together (but don’t mix so there is t a mixing of mum and baby’s blood).
Coming out roughly the centre of the placenta on the baby’s side is the umbilical cord which attaches to the fetus at the belly button (the belly button is kind of like a scar from where the umbilical cord came off). Within the cord are an umbilical vein and two umbilical arteries (sometimes only one). These allow blood to go to and from the placenta from the fetus.
Function
Providing oxygen; foetuses have a slightly different haemoglobin (Hb is the red protein that holds onto oxygen and transports it to where it’s needed). Because it is slightly different it holds onto oxygen slightly better so that when the blood in the baby’s part of the placenta comes close to the mum’s blood in her part oxygen is able to move from mum’s blood to baby’s and be picked up
Nutrients: the fetus gets all its nutrients and fluid from the mother. Some of these diffuse into the fetus’s blood from the mothers just down a concentration gradient. Other components are actively transported by proteins in the cell membranes.
Waste excretion
The fetus creates waste products, like carbons dioxide, that needs to be gotten rid of. This goes from fetus’ blood to maternal blood down the concentration gradient
Hormone production
There are a number of hormones that the placenta produces that keep the pregnancy going and also alter mum’s metabolism to free up energy for the fetus.
Protection to fetus and mother
Because the bloods of mother and fetus don’t mix, the baby is protected from mum’s immune system. If it did mix then the immune system would recognise the fetus as a foreign object and try to fight it in the same way as an infection or a transplanted organ.
The placenta also protects the fetus from infections (mum can have an infection and the fetus not be infected).
Bye bye placenta
After the baby is born, the uterus continues to contract which physically compresses the placenta. There is also loss of blood going back to the placenta from the baby as the vessels in the cord contract when the cord gets cold, and then when the cord is cut. You also get the blood vessels within the placenta and uterus contracting. There are other hormone mechanisms as well. All of these together allow the placenta to separate from the uterus without too much blood loss from mum or baby.
Extra info
The longer it takes to separate from the uterus the higher the chance of there being a large bleed from mum. One of the fastest ways to bleed to death is from a postpartum bleed. Most bleeds are small but it can be catastrophic. For this reason, in most or all developed countries, most placental deliveries are “actively managed” rather than letting it occur completely naturally. The mother is given an injection into her thigh after the baby is delivered. It is a synthetic version of oxytocin, which is a hormone that mum’s brain produces to cause the separation. This injection speeds up the separation and reduces the risk of severe PPH. The risk of severe PPH is higher in women who have had lots of previous pregnancies and they will often be given a double dose of syntocin, one into the muscle and one into a vein at the same time to offset this increased risk
I have now completed your crash course in the placenta. Feel free to forget it all
The placenta is a sort of filter that allows nutrients to pass from the mother’s bloodstream into the baby’s bloodstream.
The placenta forms from the fetus while it’s still barely more than a clump of differentiated cells. The [blastocyst](https://en.wikipedia.org/wiki/Blastocyst) implants into the uterine lining and a few of the cells in the fetus start developing into the placenta.
The placenta is mostly just a network of connected blood vessels that burrow into the uterus, seeking blood vessels from the mother’s body. The uterus forms a membrane that surrounds the ends of the blood vessels from the placenta, which fills with fluid mixed with blood from the mother. Oxygen and nutrients dissolves out of the blood from the mother and dissolves into the blood from the fetus. This way, there is no direction connection between mom and the growing baby.
The umbilical cord carries the fetus’s blood back from the placenta, full of oxygen and food and everything else it needs to grow. The placenta also carries waste from the growing fetus and dissolves it into the mother’s blood for her to expel.
A direction connection is dangerous to both the baby and mom, but mostly it protects mom. Evolutionarily speaking, it’s in the baby’s best interest to take as many resources from the mother as possible without killing her. The baby’s genes will only be passed on if it survives, and the bigger and healthier it is at birth, the better its chances of survival to adulthood. It gets just that one chance to live. The mother, on the other hand, can pass on her genes through as many babies as she can have. So although it’s in her interest to give the baby *enough*, it’s also in her interest to be able to withhold resources if food is scarce, or even to be able to spontaneously abort.
The uterine lining prevents the baby from directly connecting to the mother’s blood and acts as a filter for her. The baby can send hormone signals across the barrier to, say, increase the mother’s blood sugar, which would mean more food for the fetus (and less food for mom, or diabetes for mom). Some signaling is good, because the baby *does* need food and whatnot, which is fine. The uterus helps filter that and control that, limiting just how much the fetus can do, and preventing any problems from affecting the mother.
The placenta acts as a filter for the baby. The fetus is very vulnerable to any number of diseases. A direct blood connection would carry any viruses or bacteria. It also carries the mother’s immune system, which won’t recognize the baby’s cells and would attack.
How does the body create it? How is it structured? How does it keep the baby alive? How does it attach/detach from the uterus?
In: 2
Formation
Formed partly from stem cells from the same group that goes onto form the fetus, and partly from the endometrium, the lining of mum’s uterus. They grow blood vessels that line up very close together (but don’t mix so there is t a mixing of mum and baby’s blood).
Coming out roughly the centre of the placenta on the baby’s side is the umbilical cord which attaches to the fetus at the belly button (the belly button is kind of like a scar from where the umbilical cord came off). Within the cord are an umbilical vein and two umbilical arteries (sometimes only one). These allow blood to go to and from the placenta from the fetus.
Function
Providing oxygen; foetuses have a slightly different haemoglobin (Hb is the red protein that holds onto oxygen and transports it to where it’s needed). Because it is slightly different it holds onto oxygen slightly better so that when the blood in the baby’s part of the placenta comes close to the mum’s blood in her part oxygen is able to move from mum’s blood to baby’s and be picked up
Nutrients: the fetus gets all its nutrients and fluid from the mother. Some of these diffuse into the fetus’s blood from the mothers just down a concentration gradient. Other components are actively transported by proteins in the cell membranes.
Waste excretion
The fetus creates waste products, like carbons dioxide, that needs to be gotten rid of. This goes from fetus’ blood to maternal blood down the concentration gradient
Hormone production
There are a number of hormones that the placenta produces that keep the pregnancy going and also alter mum’s metabolism to free up energy for the fetus.
Protection to fetus and mother
Because the bloods of mother and fetus don’t mix, the baby is protected from mum’s immune system. If it did mix then the immune system would recognise the fetus as a foreign object and try to fight it in the same way as an infection or a transplanted organ.
The placenta also protects the fetus from infections (mum can have an infection and the fetus not be infected).
Bye bye placenta
After the baby is born, the uterus continues to contract which physically compresses the placenta. There is also loss of blood going back to the placenta from the baby as the vessels in the cord contract when the cord gets cold, and then when the cord is cut. You also get the blood vessels within the placenta and uterus contracting. There are other hormone mechanisms as well. All of these together allow the placenta to separate from the uterus without too much blood loss from mum or baby.
Extra info
The longer it takes to separate from the uterus the higher the chance of there being a large bleed from mum. One of the fastest ways to bleed to death is from a postpartum bleed. Most bleeds are small but it can be catastrophic. For this reason, in most or all developed countries, most placental deliveries are “actively managed” rather than letting it occur completely naturally. The mother is given an injection into her thigh after the baby is delivered. It is a synthetic version of oxytocin, which is a hormone that mum’s brain produces to cause the separation. This injection speeds up the separation and reduces the risk of severe PPH. The risk of severe PPH is higher in women who have had lots of previous pregnancies and they will often be given a double dose of syntocin, one into the muscle and one into a vein at the same time to offset this increased risk
I have now completed your crash course in the placenta. Feel free to forget it all
The placenta is a sort of filter that allows nutrients to pass from the mother’s bloodstream into the baby’s bloodstream.
The placenta forms from the fetus while it’s still barely more than a clump of differentiated cells. The [blastocyst](https://en.wikipedia.org/wiki/Blastocyst) implants into the uterine lining and a few of the cells in the fetus start developing into the placenta.
The placenta is mostly just a network of connected blood vessels that burrow into the uterus, seeking blood vessels from the mother’s body. The uterus forms a membrane that surrounds the ends of the blood vessels from the placenta, which fills with fluid mixed with blood from the mother. Oxygen and nutrients dissolves out of the blood from the mother and dissolves into the blood from the fetus. This way, there is no direction connection between mom and the growing baby.
The umbilical cord carries the fetus’s blood back from the placenta, full of oxygen and food and everything else it needs to grow. The placenta also carries waste from the growing fetus and dissolves it into the mother’s blood for her to expel.
A direction connection is dangerous to both the baby and mom, but mostly it protects mom. Evolutionarily speaking, it’s in the baby’s best interest to take as many resources from the mother as possible without killing her. The baby’s genes will only be passed on if it survives, and the bigger and healthier it is at birth, the better its chances of survival to adulthood. It gets just that one chance to live. The mother, on the other hand, can pass on her genes through as many babies as she can have. So although it’s in her interest to give the baby *enough*, it’s also in her interest to be able to withhold resources if food is scarce, or even to be able to spontaneously abort.
The uterine lining prevents the baby from directly connecting to the mother’s blood and acts as a filter for her. The baby can send hormone signals across the barrier to, say, increase the mother’s blood sugar, which would mean more food for the fetus (and less food for mom, or diabetes for mom). Some signaling is good, because the baby *does* need food and whatnot, which is fine. The uterus helps filter that and control that, limiting just how much the fetus can do, and preventing any problems from affecting the mother.
The placenta acts as a filter for the baby. The fetus is very vulnerable to any number of diseases. A direct blood connection would carry any viruses or bacteria. It also carries the mother’s immune system, which won’t recognize the baby’s cells and would attack.
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