Maggie A. Norris

The organs of the female reproductive system are concentrated in the pelvic cavity. Many of the female reproductive organs are attached to the broad ligament, a sheet of tissue that supports the organs and connects the sides of the uterus to the walls and floor of the pelvis. Ovaries The ovaries are two almond-shaped structures approximately 2 inches (5 centimeters) wide, one on each side of the pelvic cavity.

Taxonomy is the science that seeks to classify and organize living things, expressed as a series of mutually exclusive categories. The highest (most inclusive) category is domain, of which there are three: Archea, Eubacteria, Eukaryota. Each of these domains is split into kingdoms, which are further divided until each individual organism is its own unique species.

Terms that indicate direction make no sense if you're looking at the body the wrong way. You likely know your right from your left, but ignoring perspective can get you all mixed up. Stand up straight. Look forward. Let your arms hang down at your sides and turn your palms so they're facing forward. You are now in anatomical position.

Anatomy and physiology are concerned with the level of the individual body, what scientists call the organism. However, you can't merely focus on the whole and ignore the role of the parts. The life processes of the organism are built and maintained at several physical levels, which biologists call levels of organization: the cellular level, the tissue level, the organ level, the organ system level, and the organism level (shown).

Although they're astoundingly varied, cells are also remarkably alike. All cells, at least all eukaryotic cells, are alike. Plants, animals, and fungi are eukaryotes (organisms made up of eukaryotic cells), and all their cells, in all their enormous complexity and variation, are fundamentally alike.Yes, your skin cells, your kidney cells, and your bone cells are fundamentally similar to the leaf cells and root cells of a carrot; the cells of a mold, mushroom, or yeast; and the single cell of microorganisms called protists that live in water and soil.

A watery environment is a requirement for a great proportion of your body's metabolic reactions (the rest need a lipid, or fatty, environment). The body contains a lot of water: in your blood, in your cells, in the spaces between your cells, in your digestive organs, here, there, and everywhere.Not pure water, though.

The 280 days, usually expressed as 40 weeks, are the human gestational period (length of pregnancy). This period is divided, again by convention, into three trimesters, though nothing specific marks the transition from one to the next.Officially, by convention, Day 1 of a pregnancy is the first day of the woman's previous menstrual period.

One way to think of human development is as the unfolding in real time and space of a program for generating a unique biological organism. The program is launched when a new zygote comes into existence. All zygotes are created the same way and then proceed down the path of development encoded in their own species-specific and individual-specific DNA.