Child Developmental Stages
Child development comes in stages, and although not all children develop at the same rate, this timeline describes what typically occurs from the pre-natal stage through infancy and up to two years old. Pre-natal development is the most significant segment of human development. 15 days after conception the embryonic stage begins and continues until about the 8th week, or until the embryo is around an inch in length. The cells of the embryo are multiplying and taking on different functions. This critical period, the first trimester, the growing embryo is most susceptible to damage from external sources including viral infections, x-rays and other radiation, and poor nutrition. By the third week, the heart is forming and the brain and spinal cord is beginning to develop as well as the beginning of the gastrointestinal tract. During weeks four and five, the vertebra, the lower jaw, the larynx, and the ear and eye begin to develop. The heart, which is still outside the body, now beats with a regular rhythm. Arm and leg "buds" are visible with hand and foot "pads," but the embryo still has a tail and looks similar to a pig, rabbit, elephant, or chick embryo. By the time the embryo is six weeks it is approximately 1/2 inch long and weighs around 1/1000 of an ounce. The nose, jaw, palate, and lung buds are forming. The fingers and toes have formed, but may still be webbed. The tail is receding, and the heart is almost fully developed. By weeks seven and eight the embryo is growing to an inch in length and weighing up to 1/15 of an ounce (a little bigger than an aspirin). The eyes have moved forward on the face, and the eyelids and tongue begin to form. All essential organs have begun to form. The embryo now resembles a human being, with facial features and the external ears appear. Also, the beginnings of external genitalia are beginning. The circulation through the umbilical cord is well developed, and the long bones begin to...
Please join StudyMode to read the full document