The most profound change at birth is your baby’s first breath. At this point, your baby’s lungs, which were filled with fluid during pregnancy, must suddenly fill with oxygen from the air. The fluid in the lungs is removed through the blood and lymph system, and is replaced by air. Your baby’s lungs must be able to exchange oxygen for carbon dioxide. At the same time, vigorous blood circulation in the lungs will begin. The first few breaths after birth may be the most difficult breaths your baby will take for the rest of her life.
There are a couple of things that will stimulate your baby to take her first breath. Hormonal and other changes during labour slow down or stop the production of fluid in the lungs, and may initiate the reabsorption of fluid from the lungs. This process is unlikely to have occurred if labour was very short or did not occur at all, for example, if your baby was delivered by caesarean section. Furthermore, physical stimulation and handling during delivery will encourage your baby to breathe. There are probably many other factors that stimulate baby’s first breath, but they have not been identified yet.
Your baby will need to work very hard to take her first breath, and her first few breaths may be shallow and irregular. With each breath after birth, more air will accumulate in her lungs, which will make it easier for her to breathe. After a few breaths, your baby will be able to breathe more easily, and her breaths will start to become deeper and more regular.
As the fluid in your baby’s lungs is replaced by air, the increased amounts of oxygen will stimulate a blood vessel close to her heart called the ductus arteriosus to begin closing. The ductus arteriosus was important to your baby’s body before birth, to divert blood away from the lungs. After birth, your baby needs blood to circulate through the lungs, and therefore, the ductus arteriosus is no longer needed. The ductus arteriosus usually closes during the first or second day of life. At this point, your baby’s heart will pump and circulate blood in much the same way as an adult’s heart. The transition from fetal to adult circulation can take minutes or hours. Problems with your baby’s colour or breathing may be related to this delayed transition.
Answer:
Melatonin
Explanation: melatonin in the body is a natural hormones that helps in the regulations or coordination of the cycle of our sleeping and waking. It is found in the pineal glad and it is more active during night time than day time.
Teenagers most especially has different time of sleep they sleep mostly late during weekends and sleep early during weekdays.our body needs sleep so as to function properly and most times our body is also adapt to some times that we sleep. Melatonin is usually release in the body gradually around 9pm in the evening where it initiate sleep but in some people, it is when the hormones is release in an increase dose that they can fall asleep thereby shifting the time to about 11pm or 12pm before the person can fall asleep for quick sleep, melatonin supplement are used.
During the light reactions, oxygen (O2) is produced.
The frequency of the homozygous dominants will go down, the
frequency of the heterozygous genotype will go down, and the frequency of the
homozygous recessives will go up. This is because the hunting by the humans
reduces the population of individuals with the dominant trait and reduces their
chances of reproduction and the passing of their genes to the subsequent
generation.
