Reproductive cells
The eggs and sperm are the reproductive cells. Each mature reproductive cell is haploid in that it has a single set of 23 chromosomes containing half the usual DNA amount.
Except for the eggs and sperm, each cell in the human body — there are 100 trillion cells in each of us — contains the entire human genome, all the genetic information necessary to build a human being, and this information is encoded within the cell nucleus in 6 billion base pairs, subunits of DNA, packaged in 23 pairs of chromosomes, one chromosome in each pair coming from each parent.
The reproductive cells — the eggs and sperm — are thus notable exceptions to the usual rules concerning chromosomes, genes, and DNA.
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- Reproductive organs, female
they produce eggs (ova) and female hormones. Each month, during the menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a Fallopian tube to the uterus. The ovaries are the main source of female hormones (estrogen and progesterone). These hormones control the development of female body characteristics, such […]
- Reproductive system
In women, the organs that are directly involved in producing eggs and in conceiving and carrying babies; in men, the organs directly involved in creating, storing, and delivering sperm to fertilize an egg.
- Research, clinical
A study of a treatment, procedure, or medication done in a medical setting. See also clinical research trials.
- Research, controlled
A study that compared results from a treated group and a control group. The control group may receive no treatment, a placebo, or a different treatment. See also blinded study, control group, double-blinded study.
- Resect
To remove. Resect and excise are not synonymous. Excise implies total removal whereas resect need not. A surgeon may resect part or all of a tumor but if the surgeon excises the tumor, all of the tumor is removed. From the Latin resectus, from resecare, meaning to trim, prune, cut back.