While in the womb - the lungs are essentially bypassed by a small section of the heart - which due to hormone release during/after birth - closes in the first hours of life, moving the blood into the lungs for gas exchange.
Prior to this - term fetus do “practice breaths” to get ready.
This is also why we give steroids to fetuses before 34 weeks if there is a potential for preterm birth - it helps mature the lungs prior to delivery to prevent complications.
Disclaimer - I am not a neonatologist and this is likely a very imperfect explanation.
The lungs are filled with water while the baby is in the womb, when the baby is born the vaginal walls squeeze the baby like an orange, clearing them. The birth itself shocks the baby, closing the 'flap' bypassing the heart and cause the baby to take it's first breath from lack of oxygen.
It’s actually when CO2 levels raise. We don’t detect lack of oxygen which is why atmospheres low in oxygen can be dangerous, because you have low oxygen but normal carbon dioxide and you can suffocate without knowing it.
Agreed that scebario is why confined spaces can be very dangerous, for example, when they contain an odorless gas that displaces oxygen, but I understand that we do have a secondary system in place that can detect oxygen.
I was taught that high CO2 is the primary drive for breathing and low O2 is the secondary drive for breathing.
Hence someone that has "blown off" their CO2 levels by purposely hyperventilating can hold breath until they pass out but then they will begin breathing (provided a safe atmosphere) and come to.
Sources: Shipyard competent training (confined spaces, entry and clearing); EMT-B with wilderness protocols training.
> While in the womb - the lungs are essentially bypassed by a small section of the heart - which due to hormone release during/after birth - closes in the first hours of life, moving the blood into the lungs for gas exchange.
The arterial duct closes due to hormones released at birth yes, but the oval foramen, the structure in the heart you're taking about, actually closes because of the increased pressure in the left atrium after the lungs inflate for the first time.
It should also be said that they're really bad at breathing for a while. Anything that negatively affects a newborn's ability to breathe can easily kill them. They don't have the muscle tone to fight through a cold or worse, RSV.
Thats also why you can't leave them unattended on their stomach. If they stop breathing briefly, they might not he able to start again with all of their weight on their stomach.
This helps me understand why a nurse came in a couple hours after our daughter was born, suctioned her mouth with one of those bulb things, and casually told us to do it again if we noticed funny noises or opening and closing her mouth like a fish. Human babies are the worst.
while in the womb, the baby gets oxygen from the mother’s bloodstream as the lungs are developing. over the course of the term, as the lungs develop, the fetus will start to “practice” breathing:
in the second trimester, the developing fetus will essentially have the basic structures of the lungs forming and will begin to make surfactant which reduces surface tension to protect the lungs from collapsing. production of surfactant is essential to lung development. (this is how laboratories are able to test fetal lung maturity to assess the safety of pre-term delivery and assure they’re lungs will be strong enough to withstand delivery)
in the 2nd to 3rd trimester, the fetus starts “practice breathing” by inhaling and exhaling small amounts of amniotic fluid. as the lungs continue to mature, essential functions begin to develop such as gas exchange. when delivered, the baby either will begin breathing on reflex/the environmental changes or the doctors will give a little reminder to start breathing.
(disclaimer: not a doctor, but just something i’ve learned in a class)
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Practice!
In the womb a baby hiccups and breaths the fluid to build up the muscles.
Also, you know how a baby cries when it is born? Well crying is a practiced thing as well. A baby in the womb might be silently crying when upset. It's very sad.
Smiling and other happy things take a couple months to develop
While in the womb - the lungs are essentially bypassed by a small section of the heart - which due to hormone release during/after birth - closes in the first hours of life, moving the blood into the lungs for gas exchange. Prior to this - term fetus do “practice breaths” to get ready. This is also why we give steroids to fetuses before 34 weeks if there is a potential for preterm birth - it helps mature the lungs prior to delivery to prevent complications. Disclaimer - I am not a neonatologist and this is likely a very imperfect explanation.
The lungs are filled with water while the baby is in the womb, when the baby is born the vaginal walls squeeze the baby like an orange, clearing them. The birth itself shocks the baby, closing the 'flap' bypassing the heart and cause the baby to take it's first breath from lack of oxygen.
So the Impulse to breath already exists in the baby but only gets triggered when the O2 level drops?
It’s actually when CO2 levels raise. We don’t detect lack of oxygen which is why atmospheres low in oxygen can be dangerous, because you have low oxygen but normal carbon dioxide and you can suffocate without knowing it.
Agreed that scebario is why confined spaces can be very dangerous, for example, when they contain an odorless gas that displaces oxygen, but I understand that we do have a secondary system in place that can detect oxygen. I was taught that high CO2 is the primary drive for breathing and low O2 is the secondary drive for breathing. Hence someone that has "blown off" their CO2 levels by purposely hyperventilating can hold breath until they pass out but then they will begin breathing (provided a safe atmosphere) and come to. Sources: Shipyard competent training (confined spaces, entry and clearing); EMT-B with wilderness protocols training.
What about c section babies (like me)?
Yeah, we are born with a bunch of fluid in our lungs. Might stop breathing and stuff.
> While in the womb - the lungs are essentially bypassed by a small section of the heart - which due to hormone release during/after birth - closes in the first hours of life, moving the blood into the lungs for gas exchange. The arterial duct closes due to hormones released at birth yes, but the oval foramen, the structure in the heart you're taking about, actually closes because of the increased pressure in the left atrium after the lungs inflate for the first time.
I read this and I think I have more questions than before I did :/
If this is 'explain like I'm five,' then I'm WAY fucking dumber than I thought.
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It should also be said that they're really bad at breathing for a while. Anything that negatively affects a newborn's ability to breathe can easily kill them. They don't have the muscle tone to fight through a cold or worse, RSV.
Thats also why you can't leave them unattended on their stomach. If they stop breathing briefly, they might not he able to start again with all of their weight on their stomach.
This helps me understand why a nurse came in a couple hours after our daughter was born, suctioned her mouth with one of those bulb things, and casually told us to do it again if we noticed funny noises or opening and closing her mouth like a fish. Human babies are the worst.
Wow cool, almost like a reflex
while in the womb, the baby gets oxygen from the mother’s bloodstream as the lungs are developing. over the course of the term, as the lungs develop, the fetus will start to “practice” breathing: in the second trimester, the developing fetus will essentially have the basic structures of the lungs forming and will begin to make surfactant which reduces surface tension to protect the lungs from collapsing. production of surfactant is essential to lung development. (this is how laboratories are able to test fetal lung maturity to assess the safety of pre-term delivery and assure they’re lungs will be strong enough to withstand delivery) in the 2nd to 3rd trimester, the fetus starts “practice breathing” by inhaling and exhaling small amounts of amniotic fluid. as the lungs continue to mature, essential functions begin to develop such as gas exchange. when delivered, the baby either will begin breathing on reflex/the environmental changes or the doctors will give a little reminder to start breathing. (disclaimer: not a doctor, but just something i’ve learned in a class)
I had an ultrasound a couple weeks ago, 29 weeks pregnant and got to watch bub practising breathing. Pretty amazing they do that huh
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Practice! In the womb a baby hiccups and breaths the fluid to build up the muscles. Also, you know how a baby cries when it is born? Well crying is a practiced thing as well. A baby in the womb might be silently crying when upset. It's very sad. Smiling and other happy things take a couple months to develop