Prenatal development is an essential part of the process of a fetus as it represents the time when numerous important changes take place, thus helping set a context for the psychological development of the individual in the future. For instance, the brain develops during the prenatal stage but will continue growing even in the initial years of childhood. During prenatal development, the microscopic, fertilized ovum divides millions of times and develops into a child. The transformation occurs throughout three stages, including the germinal stage, the embryonic stage, and the fetal stage. The overview of the stages of prenatal development can potentially help to spell out the guiding principles of development.
In order to understand the principles of prenatal development, it is important to differentiate between the three phases. The germinal stage, which takes place during the first two weeks, occurs when tiny cell clusters divide every twelve to fifteen hours as it wends its way to the fallopian tube. At the point when the cells enter the uterine cavity, they can differentiate into layers, which will eventually become either pregnancy support structures or a child-to-be. At the embryonic stage, which lasts between the third and the eighth weeks, all of the major organs are being constructed. While the stage begins from a clump of cells, it ends with a recognizable human being. From the ninth week to birth, the fetal stage takes place, when development occurs slower, ranging from eyebrows and fingernails to the fat cushion accumulating during the final weeks of development.
The three principles of prenatal development are associated with the sequence in which various changes in the embryo and fetus take place. The first principle of human development is associated with changes in the shape of the embryo. For instance, one can notice that from a cylindrical shape, the legs and arms grow in the outward direction and then, gradually, the fingers and toes would protrude. Therefore, the growth of a human follows the Proximodistal sequence, from the interior (proximal) body parts to the outer (distal) parts. Therefore, the Proximodistal development is linked to the tendency of an embryo’s growth to begin at the center of the body and move in outward directions to include the extremities. It shows that the spine develops first, followed by limbs and then by fingers and toes.
The second principle of human development pertains to significant swelling of the head, which makes the embryo look like a mammoth head, during which arms emerge and the legs sprout. During prenatal growth, in the period between conception and five months, the head grows the most and looks disproportionate to the body; however, it slows down in growth, allowing for the full development of the limbs and the trunk. In this case, the development of the embryo takes place based on the cephalocaudal sequence, which means that it takes place from the top of the body to the bottom.
The third principle of human development is concerned with pointing out the way in which “nature starts with building blocks and then fills in the details” (Belsky 40). It shows that the head develops first before the eyes and ears or that the legs are developed before fingers and toes. This principle pertains to the mass-to-specific sequence of growth in which larger and more significant (but simpler) develop in the beginning, followed by smaller and more complex refinements that make up the important features of the body as it is developing.
Therefore, the three principles are correlated with the differences in developmental sequences, showing distinct patterns in the way in which a human embryo changes prior to being born. The Proximodistal sequence is a principle of development that takes place beginning from the interior parts of the body followed by external. The cephalocaudal sequence is based on the principle that shows that growth occurs in a sequence from head to toe. Finally, the mass-to-specific sequence is a developmental principle showing that both large movements and body parts occur before the increasingly detailed refinements.
Overall, prenatal development principles imply the various sequences of development as related to the formation of vital organs or extremities. It is notable that the three sequences can occur both simultaneously and separately from one another depending on the stage of an embryo’s or fetus’s development. For instance, according to the principles of the cephalocaudal sequence, while the head grows quicker than the arms and the legs, its development would slow down to ensure that other parts are as well-developed. Importantly, the understanding of the three principles of development is important because similar concepts apply to the stages of motor skill development after a baby is already born. The mass-to-specific sequence implies that a child would learn the general guidelines of behavior first, followed by particular rules and details of how to behave in society.
Work Cited
Belsky, Janet. Experiencing the Lifespan. 15th ed., Worth Publishers, 2018.