Development of digestive and absorptive function in the human fetus
Nutrition and Metabolism
|January 1, 1976
Insights
Digestive enzyme activity in newborns is low but increases with age. Intestinal absorption is mature at birth, though premature infants show lower fat absorption that improves quickly.
Area of Science:
- Neonatal physiology
- Gastrointestinal development
Background:
- Digestive enzyme activity and intestinal absorptive functions are critical for infant nutrition.
- Understanding these functions in newborns, especially premature infants, is essential for assessing nutritional status.
Purpose of the Study:
- To characterize the developmental status of digestive enzymes and intestinal absorptive functions in human newborn infants.
- To identify specific patterns in enzyme activity and absorption, particularly concerning fat absorption in premature infants.
Main Methods:
- Analysis of pancreatic alpha-amylase activity in mature newborn infants.
- Assessment of the developmental trajectory of other digestive enzymes with age.
- Evaluation of intestinal absorptive functions during pregnancy and in newborns.
- Monitoring of fat absorption in premature infants during the first month of life.
Main Results:
- Mature newborn infants exhibit very low but inducible pancreatic alpha-amylase activity.
- Other digestive enzymes show rapid age-related increases, nearing adult levels.
- Intestinal absorptive functions are largely developed by mid-pregnancy and are at adult levels in newborns.
- Premature infants demonstrate initially low fat absorption, which rapidly improves within the first postnatal month.
Conclusions:
- Neonatal digestive enzyme activity is characterized by low basal levels with significant inducibility, particularly for pancreatic alpha-amylase.
- Intestinal absorptive capacity is well-established at birth, ensuring efficient nutrient uptake in mature newborns.
- Premature infants require specific attention regarding fat absorption, as this function matures postnatally.
Abstract:
In the mature human newborn infant, only pancreatic alpha-amylase shows a very low but highly inducible activity. Other digestive enzymes, although not yet at adult levels, increase rapidly with age. Intestinal absorptive functions develop already during early and mid-pregnancy and are mostly at adult levels in the newborn infant. Fat absorption is usually low in the premature infant and increases rapidly during the first month.
Related Concept Videos
01:50What is Monogastric Digestion?
The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. Several other animal species also have monogastric digestive systems, including pigs, horses, dogs, and birds. This chapter, however, focuses on the human digestive system.
01:23Anatomy of the Intestines
Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, and electrolytes from food and drink also occurs in the intestine. The intestines can be divided into two structurally distinct organs—the small and large intestines.
Small Intestines
The small intestine is an ~7 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the small...
Small Intestines
The small intestine is an ~7 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the small...
01:56Gastrulation
Gastrulation establishes the three primary tissues of an embryo: the ectoderm, mesoderm, and endoderm. This developmental process relies on a series of intricate cellular movements, which in humans transforms a flat, “bilaminar disc” composed of two cell sheets into a three-tiered structure. In the resulting embryo, the endoderm serves as the bottom layer, and stacked directly above it is the intermediate mesoderm, and then the uppermost ectoderm. Respectively, these tissue strata will form...
01:14Fetal Circulation
Fetal circulation is a unique system that facilitates the exchange of gases, nutrients, and waste products between the developing fetus and the mother. This intricate process takes place through a special organ called the placenta.
Two umbilical arteries transport blood from the fetus to the placenta. At the placenta, the blood absorbs oxygen and nutrients while simultaneously eliminating waste products. This oxygen-enriched and nutrient-rich blood then returns to the fetus through one...
Two umbilical arteries transport blood from the fetus to the placenta. At the placenta, the blood absorbs oxygen and nutrients while simultaneously eliminating waste products. This oxygen-enriched and nutrient-rich blood then returns to the fetus through one...
01:27Histology of the Small Intestine
The small intestine exhibits a unique histological structure that significantly enhances its function in digestion and nutrient absorption. These structures include circular folds, villi, and various specialized cells that collectively facilitate the digestion of food.
The intestinal lining features transverse folds called circular folds, each housing fingerlike projections known as intestinal villi. These villi are covered by a layer of simple columnar epithelium, also referred to as...
The intestinal lining features transverse folds called circular folds, each housing fingerlike projections known as intestinal villi. These villi are covered by a layer of simple columnar epithelium, also referred to as...
01:15Development of the Sexual Organs in the Embryo and Fetus
Development of the reproductive organs in an embryo starts from a bipotential state. This means the early embryo can develop either male or female reproductive organs. The formation of these organs begins with the growth of gonadal ridges that arise from the intermediate mesoderm during the fifth week of development.
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the male...
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the male...