| Scrotum | External sac enclosing the testes. |
| Testes | Male gonads that produce sperm cells, a 2-5% of the seminal fluid, and secrete testosterone. |
| Seminiferous tubules | Tightly coiled tubes within the testes that produce sperm. |
| Epididymis | Portion of the testes in which sperm mature or fully develop. |
| Vas deferens | Also ductus deferens. Passageway that carries sperm from the epididymis to the ejaculatory duct. |
| Seminal vesicles | Glands located at the base of the bladder that produce around a 70% of the seminal fluid. |
| Ejaculatory duct | Duct formed by the union of the ductus deferens and the duct of the seminal vesicle, that carries the semen up to the urethra. |
| Prostate | Muscular gland in males that surrounds the first inch of the urethra. It produces almost a 30% of the seminal fluid. |
| Bulbourethral glands | Also Cowper's glands. Glands located at the base of the penis, that at the beginning of sexual arousal secrete a fluid which helps to lubricate the urethra for spermatozoa to pass through, and to help flush out any residual urine. This fluid can carry sperms from previous ejaculations. |
| Penis | Male organ of reproduction and urination. |
| Prepuce | Also foreskin. The fold of skin over the glans or tip of the penis. |
| Circumcision | Surgical removal of the prepuce of the penis. |
| Erection | Stiffening, lengthening and rising of the penis, which occurs during sexual arousal, though it can also happen in non-sexual situations. It is primarily due to the dilation of the arteries that supply blood to the penis (which allows more blood to fill the three spongy chambers in the penis) and the constriction of the veins that carry blood away from the penis. This way, more blood enters than leaves the penis until an equilibrium is reached and a constant size is achieved. |
| Ejaculation | Sudden ejection of semen from the penis. |
| Semen | Thick, whitish, somewhat sticky fluid composed of sperms and seminal fluid that is propelled out of a male's reproductive tract during ejaculation. Normal human ejaculated semen, as defined by the WHO, has a volume of 2 ml or greater, pH of 7.2 to 8.0 (slightly alkaline), sperm concentration of 20 million spermatozoa per ml or more, and a motility of 50% of the spermatozoa, with at least a 25% being able to move forward. |
| Ovaries | Female gonads in which ova are produced and that secrete estrogens and progesterone. |
| Ovarian follicles | Structures within an ovary consisting of a developing egg surrounded by follicle cells. |
| Corpus luteum | Yellowish remains of a burst ovarian follicle that secretes progesterone. |
| Ovulation | Release of a mature ovum from an ovary. |
| Fimbriae | Fingerlike projections at the end of a fallopian tube that partially surround an ovary. |
| Fallopian tubes | Also ovarian tubes. Tubes connecting an ovary to the uterus and through which an ovum is transported. They are the place of fertilization. |
| Uterus | Also womb. The hollow organ in females that receives, retains, and nourishes a fertilized ovum or egg. |
| Myometrium | Middle layer of the uterus composed of interwoven muscle cells. |
| Endometrium | Inner layer of the uterus that provides nourishment for a developing embryo and fetus and that sloughs off during the regular menstrual cycle. |
| Cervix | Lower necklike portion of the uterus leading into the vagina. |
| Vagina | Muscular tube in women that extends from the cervix of the uterus to the vaginal opening. |
| Vulva | Female external genital organs, composed of the mons pubis, the labia majora, the labia minora, the clitoris, the urethral opening, the vaginal opening and the greater vestibular glands. |
| Mons pubis | Fatty, rounded, hairy area at the top of the vulva. |
| Labia majora | Outer, hairy skin folds of the vagina. |
| Labia minora | Inner skin folds of the vagina. |
| Clitoris | Small protruding mass of erectile tissue at the top of the labia minora. |
| Greater vestibular glands | Pair of mucus-secreting glands that lubricate the lower portion of the vagina. |
| Hymen | Thin membrane partially covering the external opening of the vagina. |
| Menarche | Beginning of menstruation or the first menstrual period. |
| Menopause | Period in a woman's life when menstrual activity ceases. |
| Menstruation | Also menses. Periodic (monthly) discharge of blood, secretions, tissue, and mucus from the endometrium in the absence of pregnancy. |
| Gonads | Sex organs in which reproductive cells develop. |
| Gametes | Reproductive or sex cells. They are different to any other cell in the body in which they only have half of the chromosomes than a normal somatic cell. |
| Ova | Female gametes or eggs (singular: ovum). |
| Zygote | Fertilized ovum. By successive mitosis, it will convert into an embryo, then a fetus, and finally a newborn. |
| Sperm | Also spermatozoon. Mature male sex or reproductive cell. They need to be produced at a slightly lower temperature than the usual in the inside of the human body. |
| Acrosome | Tip of the head of a sperm cell that contains enzymes to digest the membrane of an ovum. |
| Chorion | The outermost membrane that surrounds the embryo/fetus during pregnancy. It is in contact with the amnion and generates the placenta. |
| Amnion | Fluid-filled sac that surrounds a developing embryo/fetus. It provides room and cushioning to the embryo/fetus. |
| Placenta | Temporary organ developed after the implantation of an embryo, when the chorionic villi invade the endometrium. It provides nutrients to a developing fetus, carries away wastes, and produces hormones such as estrogens and progesterone. |
| Umbilical cord | Structure that connects the embryo/fetus to the placenta. |
| Alveolar glands | Glands within the mammary glands that produce milk. |
| Lactiferous ducts | Ducts that carry milk from the alveolar glands to the surface of the nipple of a breast. |
| Areola | Circular, darkened area surrounding the nipple of each breast. |
| Luteinizing hormone | Hormone secreted by the anterior pituitary that stimulates, in women, ovulation and the release of estrogens and progesterone by the ovaries and, in men, the secretion of testosterone by the testes. |
| Follicle-stimulating hormone | Hormone produced by the anterior pituitary gland that stimulates the development of follicles in the ovaries of females and sperm in the testes of males. |
| Testosterone | Male hormone secreted by the testes that stimulates the growth of the male reproductive organs and brings about the secondary sex characteristics. |
| Estrogens | Female hormones secreted by the ovaries that bring about the secondary sex characteristics and regulate the female reproductive cycle. |
| Progesterone | Female hormone secreted by the ovaries that makes the uterus more ready to receive a fertilized ovum and regulate the female reproductive cycle. |
| Prolactin | Hormone secreted by the anterior pituitary that stimulates the mammary glands to produce milk during nursing. |
| Oxytocin | Hormone produced by the hypothalamus and stored in the posterior pituitary that stimulates contraction of the uterus during childbirth and secretion of milk during nursing. |