Stages of Development - Essay Example

Stages of Development Number Changes in Maternal Body during Pregnancy Pregnancy is normally associated with sudden increase and changes in the function of hormones such as estrogen and progesterone. These changes affect mood, create glow of pregnancy, significantly help in the development of fetus and alter the physical effect of exercise and physical activity on the body. Estrogen enables the uterus and placenta to improve the vascularization, transfer nutrients and support the developing baby.

Estrogen levels shoot steadily during pregnancy and reach their peak in the third trimester resulting in nausea and enlarged breasts (Fuchs, 1983). Progesterone levels also shoot up during pregnancy and function to cause loosening of ligaments and joints throughout the body, cause internal organs such as ureters to enlarge and importantly transform the uterus to a size that can accommodate a full pregnancy. The hormones make exercise difficult because of the loosened ligaments. The woman’s posture changes, breast enlarge, abdomen transform into a convex shape increasing the curvature of her back (which may often result in changes in sense of balance).

Weight gain during pregnancy slows down blood and fluid circulation. As a result, pregnant women retain fluids and experience swelling of legs, feet, hands and even face. Some women experience vision changes during pregnancy characterized by increased myopia and abnormal hair and nail growth rates. Apart from increased metabolic rates due to high demands for nutrients, women also experience taste and smell changes along with skin changes such as development of stretch marks (Fuchs, 1983).Germ Layers In the third week of pregnancy, gastrulation begins with the appearance of a primitive streak which establishes the long axis of the embryo.

Gastrulation involves the transformation of the two-layered embryonic disc into a three layered embryo with three primary germ layers; the ectoderm (develops into the epithelial lining of the gut, respiratory and urogenital systems and associated glands), the mesoderm (develops into all tissues not formed by ectoderm or endoderm such as the muscle tissue) the endoderm (develops into structures of the nervous system and the epidermis) (Goodwin, 1994).Events during Fetal Stage of Development Fertilization of the egg by the sperm results in the formation of a zygote which travels down the fallopian tube and divides into a ball of cells.

The zygote continues to divide into an inner group of cells with an outer shell collectively called the blastocyst. Blastocyst moves to the uterus around day 5 and implants onto the uterine wall around day 6 for nourishment. The inner group of blastocyst cells results in embryo while the outer group forms the membranes that nourish and protect the membrane. Embryo differentiates over the gestation period into various cell types that make up the human being such as blood cells, kidneys cells and nerve cells.

There’s rapid growth and baby’s external and internal features begin to take form as baby approaches birth (Winick, 1974).Stages in the Development of Human Life The stages of growth that a person goes through are infancy, early childhood, childhood, late childhood, adolescence and adulthood. Infancy dates from birth to around 18 months when bones are still soft and flexible. Baby learns to sit, crawl and stand. The baby becomes prone to crying to get what it needs and develops ability to recognize parents and siblings (Dudley, 2001).

Early childhood ranges from 18 months to three years during which time the baby learns to walk and talk, arms and legs get longer, learns to use toilet and is not yet ready to share or play interactively with others. Childhood stage on the other hand, occurs from 3-6 years when baby begins to lose milk teeth, learns to behave while in a group, learns to play interactively and make friends as physical contact becomes less frequent. With late childhood, appetite increases, sexual maturity begins, individual acquires high-level thinking skills, self-centeredness lessens and one begins to pick friends from same sex.

Adolescence is the period between childhood and adulthood marked by rapid physical growth/ changes with body starting to look more like an adult. One also begins to question self and starts enjoying participation in adult talk. Friends’ views at this stage become important and one frequently shifts from happiness to loneliness in short stints. Adulthood starts from around the twenties marked with a slow regression of the five senses, bones become brittle with slow loss of calcium in the bones and stiffening of joints (Dudley, 2001).

ReferencesDudley, W. (2001). Pregnancy. San Diego, CA: Greenhaven Press. Fuchs, F. (1983). Endocrinology of pregnancy (3rd ed.). Philadelphia: Harper & Row. Goodwin, J. (1994). Pregnancy. London: Ward Lock. Winick, M. (1974). Nutrition and fetal development. New York: Wiley.