During fetal development, what keeps the lungs inflating? Fetal lung fluid is continuously created and helps to keep the fetal lung inflated at a modest positive pressure compared to the amniotic fluid pressure, which is essential for optimal lung development.
What is required for the development of the foetal lung?
Your baby gets oxygen from your bloodstream through the placenta during pregnancy. So, even though he won’t need lungs until he’s born and takes his first breath, his respiratory system has been preparing all along.
The process begins at 6 weeks of pregnancy, when the front wall of the tube that will become your baby’s esophagus forms a small pouch of tissue called a lung bud. This single bud will split into two separate buds (one for each lung) over the next week, and the windpipe will begin to form between them.
The lung buds begin to branch internally about 8 weeks, forming a system of tubes (bronchi) that join with the windpipe to form a respiratory “tree.” Two bronchi form and link to each lung at initially. Smaller branches emerge off these main bronchi as the weeks pass, and the branches get smaller and smaller as more are added.
The tiniest tubes (bronchioles) begin to grow at the terminals of the branches at around 18 weeks. Respiratory sacs, which eventually form the alveoli, develop at the end of these tiny tubes.
These sacs will become entangled with small blood arteries by the time your baby is born. The process of “gas exchange” permits oxygen and carbon dioxide to flow into and out of the bloodstream. This allows oxygenated blood to flow through the arteries to all of the body’s organs and tissues, while carbon dioxide is returned to the lungs via the veins.
These respiratory sacs expand and increase from 24 weeks of pregnancy until your child is roughly 8 years old, adding greater surface area for the exchange of oxygen and carbon dioxide. They begin producing a material called surfactant between 26 and 29 weeks, which covers the alveoli and keeps them inflated when there isn’t enough air in the lungs (when exhaling, for example).
Even while your kid won’t be able to breathe on his own until birth, about 26 weeks, he begins practicing by inhaling and exhaling little amounts of amniotic fluid. This procedure is necessary for lung development and assists your baby in preparing for life outside the womb.
Gas exchange in your baby’s tiny lungs may be possible by 28 weeks of pregnancy, even if the alveoli haven’t fully formed. There is also not enough surfactant to support the baby’s independent breathing. If your baby is born right now, he will require extensive medical attention, including surfactant therapy. As a result of his early birth, he may have lifelong respiratory issues.
There may be enough surfactant to maintain lung function by 35 weeks of pregnancy, though he’ll still require assistance breathing. He may need to stay in a neonatal intensive care unit, which is a specialist hospital for premature babies (NICU).
Your baby’s lungs have roughly 150 million alveoli by 40 weeks, ready to take over breathing once he’s born.
So, how does your child know when it’s time to take his first breath? It’s most likely a reflex reaction to being touched for the first time and being exposed to air. (Contrary to popular belief, slapping a baby’s buttocks isn’t essential, though some babies may benefit from a light towel rub.)
When your baby takes his first breath, his lungs expand and any fluid in the alveoli is replaced with air. Following that, the alveoli begin the life-sustaining process of gas exchange.
What causes the lungs to expand during childbirth?
While in the womb, the placenta of the mother helps the infant “breathe.” The blood in the placenta transports oxygen and carbon dioxide. The majority of it is directed to the baby’s heart and circulated throughout his or her body.
The baby’s lungs are packed with fluid when he or she is born. They aren’t inflated in any way. Within 10 seconds of delivery, the infant takes its first breath. As the newborn’s central nervous system reacts to the abrupt change in temperature and environment, this breath sounds like a gasp.
A variety of changes occur in the infant’s lungs and circulatory system when the baby takes his or her first breath:
- The amount of oxygen in the lungs causes the blood flow resistance in the lungs to decrease.
- The lungs expand and begin to act on their own, transporting oxygen into the circulation and eliminating carbon dioxide through breathing out (exhalation).
A developing baby generates roughly twice the amount of heat as an adult. Through the skin of the developing fetus, the amniotic fluid, and the uterine wall, a little amount of heat is evacuated.
The newborn begins to lose heat soon after birth. The brain receives messages from the skin receptors that the baby’s body is cold. Brown fat, a form of fat found only in fetuses and newborns, is burned to generate heat in the baby’s body. Shivering in newborns is uncommon.
The liver serves as a storage location for sugar (glycogen) and iron in babies. The liver has several functions when a newborn is born:
- It makes a protein that aids in the breakdown of bilirubin. Newborn jaundice can occur if the baby’s body does not adequately break down bilirubin.
The baby creates a tarry green or black waste matter called meconium in late pregnancy. The medical word for a newborn infant’s first stools is meconium. Amniotic fluid, mucus, lanugo (the fine hair that covers the baby’s body), bile, and cells shed from the skin and intestinal system make up meconium. The infant may pass feces (meconium) while still within the uterus in some situations.
By 9 to 12 weeks during the pregnancy, the developing baby’s kidneys are generating urine. The newborn will normally urinate within the first 24 hours of life after birth. The kidneys gain the ability to keep the body’s fluid and electrolyte balance in check.
After birth and over the first two weeks of life, the rate at which blood filters through the kidneys (glomerular filtration rate) increases dramatically. Even so, it takes some time for the kidneys to catch up. In comparison to adults, newborns have less ability to eliminate excess salt (sodium) or to concentrate or dilute urine. Over time, this ability improves.
The immune system develops in the baby and continues to mature during the first few years of life. The environment inside the womb is quite sterile. However, the newborn is exposed to a range of microorganisms and other potentially disease-causing substances as soon as they are born. Despite the fact that newborn infants are more susceptible to infection, their immune systems are capable of combating pathogenic germs.
Antibodies from their mother are carried by newborns and give protection against infection. Breastfeeding also boosts a baby’s immune system.
The skin of a newborn varies depending on how long the mother has been pregnant. The skin of premature babies is thin and translucent. A full-term infant’s skin is thicker.
- Lanugo, a fine hair, may cover the skin of the infant, especially in premature neonates. Within the first few weeks of the baby’s existence, the hair should fall off.
- The skin may be covered in vernix, a thick, waxy substance. While floating in amniotic fluid in the womb, this material protects the infant. During the baby’s first bath, Vernix should be washed away.
- Cracking, peeling, or blotchy skin is possible, although it should improve over time.
In the lungs, what is surfactant?
Mutations in numerous genes, including SFTPB, SFTPC, and ABCA3, induce surfactant deficiency. Surfactant production is influenced by each of these genes. Surfactant creation and release is a complicated process. Surfactant is made up of phospholipids and proteins that are bundled in cellular structures called lamellar bodies. These structures are also crucial for certain surfactant protein processing, which is required for the proteins to mature and function. Surfactant is a substance that is secreted by lung cells and travels across the tissue that surrounds alveoli. This chemical reduces surface tension, making breathing easier and preventing the alveoli from collapsing following exhale.
Surfactant protein-B (SP-B) and surfactant protein-C (SP-C), two of the four proteins in surfactant, are encoded by the SFTPB and SFTPC genes, respectively. These two proteins aid in the surface tension-lowering property of surfactant by spreading it across the surface of the lung tissue. SP-B is also involved in the creation of lamellar bodies.
Surfactant dysfunction, often known as SP-B deficiency, is caused by mutations in the SFTPB gene. These mutations cause mature SP-B to be reduced or absent. Furthermore, SFTPB gene mutations result in aberrant SP-C processing, resulting in a paucity of mature SP-C and an accumulation of unprocessed forms of SP-C. Surfactant composition and function are altered as a result of these modifications. Surface tension in the alveoli rises when effective surfactant is lost, producing significant breathing difficulty. The severity of the signs and symptoms of SP-B deficiency may be explained by the combination of SP-B and SP-C dysfunction.
Surfactant dysfunction, also known as SP-C dysfunction, is caused by mutations in the SFTPC gene. These mutations cause a decrease or absence of mature SP-C, as well as the accumulation of aberrant forms of SP-C. It’s unknown which of these consequences produces SP-C dysfunction’s signs and symptoms. A lack of mature SP-C might result in an irregular surfactant composition and reduced surfactant function. According to studies, improperly processed SP-C proteins take on an incorrect three-dimensional shape and aggregate inside lung cells. These misfolded proteins could cause a physiological reaction that leads to cell death and damage. Surfactant production and release may be disrupted as a result of this damage.
The ABCA3 gene directs the production of a protein present in the membrane that surrounds lamellar bodies. Phospholipids are transported into lamellar bodies, where they create surfactant, by the ABCA3 protein. The ABCA3 protein appears to play a role in lamellar body formation as well.
ABCA3 gene mutations, which induce a kind of surfactant malfunction known as ABCA3 deficiency, cause the protein’s function to be reduced or absent. The transport of surfactant phospholipids is reduced when the ABCA3 protein is not functioning. Furthermore, lamellar body formation is hampered, resulting in aberrant SP-B and SP-C processing. Surfactant composition and function are altered when the ABCA3 gene is mutated. It’s been reported that mutations that completely disable the ABCA3 protein produce severe surfactant dysfunction, while variants that leave some ABCA3 activity generate milder symptoms.
What are the phases of lung development in a foetus?
On day 22, the lower respiratory system begins to form, including the trachea, lungs, bronchi, and alveoli. The embryonic, pseudoglandular, canalicular, saccular, and alveolar stages are the five stages of the process. Despite the fact that the process begins early in fetal development, complete maturation does not occur until the child is about 8 years old. This developmental delay is critical in premature babies, whose survival is dependent on the stage of development of their respiratory tract at the time of birth.
Is practising breathing equivalent to having developed lungs?
The developing fetus will begin to inhale tiny bits of amniotic fluid during weeks 10 and 11 of pregnancy. This is a good example “Inhalation” is more akin to swallowing. It aids the development of the baby’s lungs. A baby will begin to practice by the 32nd week of pregnancy “Compression and expansion of the lungs are involved in “breathing-like” actions that are less like swallowing.
Even if the baby’s lungs aren’t fully grown at 32 weeks, a baby born at this point has a good chance of surviving outside the womb.
The breathing exercise is a developmental milestone that ensures a successful first cry for the new newborn. At 36 weeks, the baby’s lungs are deemed developed. A newborn has received at least four weeks of breathing practice by that point.
Dexamethasone helps foetal lungs grow.
Antenatal steroids (dexamethasone or betamethasone) can pass through the placenta and help the fetal lung and brain develop. Antenatal hormones can decrease fetal lung fluid by activating ENaCs, stimulate surfactant protein and lipid synthesis, and change preterm responses to oxidative stress in the lungs.
What is the key component that causes a newborn child to start breathing?
Although the fetus “practices” breathing in the uterus by inhaling amniotic fluid, there is no air and hence no genuine opportunity to breathe. (The fetus also doesn’t need to breathe because the placenta provides all of the oxygenated blood it need.) The partially deflated lungs are filled with amniotic fluid during pregnancy and have relatively little metabolic activity. A number of variables encourage babies to take their first breath shortly after birth. For starters, labor contractions restrict umbilical blood arteries, limiting oxygenated blood supply to the fetus and raising blood carbon dioxide levels. Acidosis is caused by high carbon dioxide levels, which excite the respiratory center in the brain, causing the newborn to take a breath.
After mucus is aspirated from the infant’s mouth and nose, the first breath is usually taken within 10 seconds of delivery. The initial few breaths nearly fill the lungs to capacity, lowering lung pressure and resistance to blood flow, triggering a massive circulatory reorganization. The alveoli in the lungs open up and the capillaries in the alveoli fill with blood. The amniotic fluid in the lungs drains or is absorbed, and the lungs take over the placenta’s job of exchanging carbon dioxide for oxygen through respiration.
What is the definition of neonatal resuscitation?
Neonatal resuscitation is a set of emergency operations carried out by a doctor to help newborn newborns who are not breathing, gasping, or have a weak heartbeat when they are born. A doctor’s abilities enable him or her to save the lives of newborn babies.
Around one-quarter of all newborn deaths occur due to a shortage of oxygen (asphyxia) at birth, which can be avoided with good and prompt resuscitation.
Do newborns breathe while still in the womb?
The air we inhale does not exist in the womb, hence babies do not “breathe” in the classic sense.
However, babies do practice breathing, referred to as fetal breathing motions, long before they leave their safe uterine environment. Amniotic fluid is brought in and out of the lungs by muscle contractions, which is thought to help develop the muscles involved in preparing for life outside the womb. It may also encourage the formation of alveoli, which are tiny air sacs on the lungs that exchange oxygen and carbon dioxide with the blood.
Fetal breathing motions occur as early as week 10 of pregnancy, but they become more noticeable around week 20. Practice breathing isn’t done all the time because it’s not vital for survival. In fact, newborns can continue for several hours without generating any kind of respiratory movement. Practice breathing happens around 10% to 20% of the time by weeks 24 to 28, increasing to 30 to 40% of the time by week 30.
Another clue that all is well is seeing these respiratory motions on an ultrasound during the third trimester.
In a foetus, what is surfactant?
Surfactant is a liquid produced by the lungs that maintains the openness of the airways (alveoli). After delivery, this liquid allows newborns to breathe in fresh air. At around 26 weeks of pregnancy, an unborn infant begins to produce surfactant.