The gastrointestinal system in newborn
Gastrointestinal is a digestive tract starting from the mouth to the anus, including oropharynx, esophagus, stomach, small intestine, and large intestine. The digestive tract (gastrointestinal), food is a channel receiving food from the outside and preparing it to be absorbed by the body of the system digestion (mastication, ingestion, and mixing). It is processed with enzymes and liquid substances that stretch from the mouth to the anus. Newborns must begin to feed, digest and absorb food after birth, as the placenta has done this function.
Before birth, the fetus is quite a month to practice sucking and swallowing behavior. At birth, advanced vomiting and cough reflexes have disappeared. The ability of a newborn baby to swallow and digest food from outside is quite limited. Most of these limitations require various enzymes and digestive hormones that can be found in the digestive tract (starting from the mouth to the intestine).
The ability of carbohydrate absorption in newborns is less efficient, while monosaccharide (glucose) absorption has been efficient. Regurgitation in newborns is caused by an incomplete heart sphincter, lower esophageal junction, and stomach. Gastric capacity in term infants is very limited, the size is less than 30cc. This is because the newborn’s intestine is relatively immature and the muscular system that makes up the organ is thinner and less efficient compared to adults. As a result, peristaltic waves are difficult to predict.
The folds and villi of the intestinal wall have not fully developed. Epithelial cells that line the small intestine of newborns do not change rapidly, thus increasing the most effective absorption. Early oral feeding stimulates the intestinal lining to mature by increasing rapid cell turnover and the production of microvillus enzymes. Immature epithelial cells affect the intestine to protect themselves from very dangerous substances.
In early life, newborns face the process of closing the intestine (the intestinal epithelial surface becomes not permeable to the antigen). Before closing the baby’s intestine it will be susceptible to viral/bacterial infections and also to allergen stimulation through absorption of large molecules by the intestine. Colon newborns are less efficient at storing fluids than the colon of adults so babies tend to experience fluid loss compilation, such as diarrhea disorders.
Important factors in the neonatal digestion system
- Digestive Organs
Here are several the digestive tract. They are oris (mouth), pharynx, esophagus (esophagus), small intestine, colon, rectum, and anus.
- Establishment of Digestive Enzymes in Infants
Important enzymes for digesting carbohydrates, proteins, and simple fats are formed in week 36-38 of gestational age. Newborns are sufficient if they can swallow, digest, metabolize and absorb simple proteins and carbohydrates and emulsify fat. Pancreatic amylase is deficient for the first 3 – 6 months after birth. As a result, newborns cannot digest complex types of carbohydrates such as in cereals.
The intestine of the newborn is relatively immature. The muscular system that makes up the organ is thinner and less efficient than in adults so that the peristaltic wave cannot be predicted. The folds and villi of the intestinal wall have not been completely developed. Epithelial cells as small line intestine of newborns do not change rapidly, thus increasing the most effective absorbs. Starting of oral feeding stimulates the lining of the intestine to mature by increasing rapid cell turnover. There are some of the products of the enzymatic enzyme, such as amylase, trypsin, and pancreatic lipase. The midwife’s support for immediate feeding of newborns helps the maturation of the ability of this small intestine.
Physiological Adaptation of the Baby’s digestive system
The fetus begins to show swallowing movement activity for 14 weeks’ gestation. The active sucking movement appears at 26-28 weeks. Bile fluids are produced from the end of the first trimester, followed by all other digestive enzymes. The digestive process has not been active. The need for nutrition is not fulfilled with the digestive system but is obtained from the placenta. Feeding reflexes in the fetus in the uterus have begun to be seen from the activity of swallowing amnion and sucking. Meconium, the main content especially in the digestive tract of the fetus, appears to begin at the age of 16 minutes. Meconium is not released as long as the fetus in the uterus (no defecation process occurs), only meconium urine since peristalsis is not active except in fetal distress. In experiencing fetal distress fetuses, there is pressure on the abdomen and the anal spingter relaxes so that the meconium stored in the intestine comes out and mixed with amniotic fluid. Important enzymes for digesting carbohydrates, proteins, and simple fats at 36-38 weeks of gestation have begun to be formed to prepare for birth (the life of an extrauterine fetus). The main fetal oxygenation remains from the maternal-fetal circulation through the placenta and umbilical cord.
Preterm neonates can digest and absorb milk from birth. Specific growth factors in milk are important to promote post-natal digestion. The neonatal intestine has immature digestive and absorption capacity but there are several compensation mechanisms, especially for infants who get breast milk. The cardiac sphincter between the esophagus and stomach in the immature neonate undergoes relaxation so that it can cause food regurgitation immediately after administration. Regurgitation can also occur because of the control of not perfect innervation in the stomach.
At birth, newborn gastric capacity is around 6 ml/kg body weight, or on average around 50-60 cc, but soon increases to around 90 ml for the first few days of life. The stomach will be empty in 3 hours for food intake and empty in 2 to 4 hours.
Newborn has an intestine. This organ is longer in size than the size of a baby. This condition causes the surface area to absorb more widely. Bowel sounds in normal circumstances can be heard in the 4 abdominal quadrants especially in the first hour after birth. This process is due to the baby swallowing air while crying and the sympathetic nervous system stimulates peristaltic. At birth the gastrointestinal tract is sterile. Once the baby is exposed to the outside atmosphere and fluids begin to enter, bacteria can enter the digestive tract. Normal intestinal flora will form within the first few days of neonates. Even though the digestive tract is sterile at birth, most bacterial babies can be cultured within 5 hours after birth. This bacterium is important for digestion and the synthesis of vitamin K.
- Eating Reflexes
From birth, a normal baby can suck from the nipple, get the milk to the back of the mouth and swallow it for 5-10 minutes while breathing normally. There are an innate reflex and behavior process. This is increasingly clear about one hour after delivery, including the ability to move from the mother’s abdomen to the breast. Also, coordinated hand activities, movements to look for the nipples, attach to the breast and eat greedily before the baby sleeps.
Touch on the ceiling triggers reflexes to suck. The neonate shows the work of the rhythmic jaw, which triggers negative pressure and the work of the tongue. Then jaw peristalsis squeezes milk from the breast and removes it from the throat which then triggers the reflex to swallow. In a normal neonate, this suckling reflex is quite strong at birth and has been seen in premature infants since around 32 weeks. The very premature babies and those with the risk of illness or very low birth weight show a marked decrease or absence of reflexes. Other babies with eating problems have physical disorders such as cleft lip or palate. Also, for those affected by sedation or obstetric analgesia or severe stress during labor.
The sucking and swallowing reflexes are aided by a special morphological configuration of the neonate’s mouth where the soft palate is proportionally longer. Neonates also have an extrusion reflex in response to the presence of solid or half-solid material in its mouth. This reflex disappears at the age of 4-6 months and is replaced by a pattern of rhythmic biting movements. That coincides with the growth of the first tooth at the age of 7-9 months.
The first stool excreted by a baby is called meconium. The characteristic of meconium is dark, greenish black, thick, the consistency as bitumen, soft, odorless, and sticky. Meconium release a mixture of mucus, epithelial cells, fatty acids, and bile pigments (which causes distinctive color greenish black).
Scientifically, meconium comes from:
o mucous cells in the gastrointestinal wall experience desquamation and loss
o A liquid/ enzyme secreted along the digestive tract, from saliva to digestive enzymes
- Amniotic fluid is taken by the fetus, which sometimes also contains lanugo and cells from the fetal skin or the felt out the amniotic membrane.