The first week of an embryo's life is critical to its survival. During this time, the embryo must undergo genetic, metabolic and developmental changes that allow for implantation in the uterine lining. The mother's menses will cease, and...
From the time of conception until life’s end, the human being continually develops, ever changing, ever growing. The miracle of life begins at fertilization, when two cells, an egg and a sperm, unite, each carrying half of the genetic...
The first few weeks of fetal development are fraught with peril for the developing embryo. Any disruption or error in fetal development during the weeks when organs and major body systems are forming can result in congenital defects. Maternal...
Neural tube defects are the result of failed development of the brain and spinal cord during embryonic development. These defects include spina bifida (literally, open spine) and anencephaly (no head). A considerable number of human studies have...
Testicular cancer is a rare but potentially serious problem that may develop in one or both of a man's testicles. Fortunately, testicular cancer is highly treatable and curable. According to the American Cancer Society, about 90 percent of...
Testicular cancer occurs in men, typically around the age of 30 when normal cells in the testis change and become tumorigenic. The majority of testicular tumors originate from germ cells. While most testicular tumors respond favorably to radiation...
There are numerous diseases associated with the muscular system. According to the U.S. National Library of Medicine and the National Institutes of Health, muscular system disorders can cause pain, weakness and even paralysis, and possible causes...
Rhabdomyoscarcoma is a type of soft tissue cancer found mostly in muscles connected to bone. Tumor locations are normally found in the head and neck, bladder or abdomen. Malignant tumors of this type are fast-growing. Rhabdomyosarcoma accounts...
According to the National Cancer Institute (NCI), there are more than 100 different types of cancer. Cancers are categorized by the organ involved and the type of cell that gave rise to the cancer. The four overarching groups of cancerous tumors...
Ovarian cancer is a gynecologic cancer that arises from the ovaries. There are various types of ovarian cancer, depending on where in the ovaries the cancer started, and how the cells look under the microscope. The American Cancer Society lists...
Germ cell tumors are uncommon neoplasms that develop from the primitive cells that give rise to eggs and sperm. These tumors most commonly develop in the ovaries and testicles but may occur anywhere in the body, including the brain. Germ cell...
The American Cancer Society reports approximately 22,000 brain and spinal cord cancers were diagnosed in the U.S. in 2009. Glioblastomas and meningiomas are the most common brain and spinal cord tumors in adults; embryonal tumors and pilocytic...
Testicular tumors are tumors that develop in the cells of the testicles, the egg-shaped male reproductive glands in the scrotum. There are numerous kinds of testicular tumors, but treatment with surgery, radiation and/or chemotherapy has produced...
Embryonic abnormalities occur very early in pregnancy, sometimes even before the mother knows she has become pregnant. Embryonic abnormalities can result in devastating congenital birth defects. Some birth defects can be prevented before pregnancy...
The embryonic stage of human development starts after implantation of the zygote, which occurs nearly two weeks after conception, and persists until eight weeks of gestational age, at which point the developing baby is considered a fetus. During...
Prenatal vitamins are daily supplement pills formulated for pregnant women. They don't contain calories, so they can't foster cellular growth, but they're important to cellular health and well being. While they don't help your embryo grow fast,...
Babies are usually conceived in the middle of a woman's menstrual cycle, about two weeks after the start of her period. When she goes to the doctor for confirmation of a pregnancy, he'll calculate an estimated due date that's 40 weeks from the...
Stem cells are unlike other cells because they can regenerate and differentiate into various kinds of cells. Stem cells occur during embryonic development and also are found in the adult body. They show promise for treating many health disorders.
The National Cancer Institute reports that more than 35,000 people each year in the United States are diagnosed with a primary brain tumor, meaning a tumor that originated in the brain. There are three major parts of the brain which control...
Within stem cells lie the capability to create every part of your body you need to live. From the time you were conceived, these versatile little cells replicated and developed your organs, tissues and functions. Through research, scientists hope...
The conception of a new human being occurs when the sperm from the father unites with the egg from the mother, resulting in a fusion of both parents' genetic material. Fertilization occurs soon after ovulation, usually in the mother's fallopian...
Each human life begins with a single cell, and expands into trillions of cells by adulthood. The cells of the body vary in their appearance and behavior, and carry out essential processes required to sustain life. Cells can be loosely classified...
The average length of time for prenatal development is 38 to 40 weeks after conception. During this time, a baby will develop from a nearly invisible group of cells to a full-term infant. Prenatal development is divided into three stages: the...
An embryo starts as a fertilized egg and continues through various developmental stages for eight weeks post-fertilization (10 weeks of pregnancy), when the embryo becomes a fetus. These embryonic stages are critical for organ and limb...
Diabetes is a disease in which blood sugar levels are too high. A hormone called insulin helps sugar get into cells, giving them the energy they need. Depending on the type of diabetes, insulin production is impaired or cut off totally. The goal...
Fetal development begins before a pregnancy may even be noticed, and the fetus undergoes rapid development in the 40 weeks of gestation spent in the mother's uterus. According to the University of Maryland Medical Center, the three main stages of...
The term "radiation" encompasses a host of physical phenomenon--for instance, visible light is a form of radiation, albeit a harmless one--but most people use the word to refer to the sort of radiation capable of doing biological harm. The general...
A pregnancy generally lasts for 40 weeks and is calculated from the first day of a woman's last period, says the American Pregnancy Association. Pregnancy is divided into three trimesters, each lasting about 12 to 14 weeks. The pregnancy then...
After the mother's egg cell is fertilized in one of the fallopian tubes, it embeds itself in utero--meaning, in the uterus--where it develops into a full-term baby over approximately 38 weeks. This developmental process is impressively consistent...
