Measurements and the Metric System
Measurements and the Metric SystemMeasurementUnitAbbreviationMetric EquivalentApproximate Standard EquivalentLengthnanometernm1 nm = 10−9 m· 1 mm = 0.039 inch· 1 cm = 0.394 inch· 1 m = 39.37 inches· 1 m = 3.28 feet· 1 m = 1.093…
Organogenesis and Vertebrate Formation
Gastrulation leads to the formation of the three germ layers that give rise, during further development, to the different organs in the animal body. This process is called organogenesis. Organogenesis is…
Fertilization and Early Embryonic Development
The process in which an organism develops from a single-celled zygote to a multi-cellular organism is complex and well-regulated. The early stages of embryonic development are also crucial for ensuring…
Human Pregnancy and Birth
Pregnancy begins with the fertilization of an egg and continues through to the birth of the individual. The length of time of gestation varies among animals, but is very similar among the…
The Ovarian Cycle and the Menstrual Cycle
The ovarian cycle governs the preparation of endocrine tissues and release of eggs, while the menstrual cycle governs the preparation and maintenance of the uterine lining. These cycles occur concurrently and are coordinated…
Hormonal Control of Human Reproduction
The human male and female reproductive cycles are controlled by the interaction of hormones from the hypothalamus and anterior pituitary with hormones from reproductive tissues and organs. In both sexes,…
Gametogenesis (Spermatogenesis and Oogenesis)
Gametogenesis, the production of sperm and eggs, takes place through the process of meiosis. During meiosis, two cell divisions separate the paired chromosomes in the nucleus and then separate the…
Female Reproductive Anatomy
A number of reproductive structures are exterior to the female’s body. These include the breasts and the vulva, which consists of the mons pubis, clitoris, labia majora, labia minora, and…
