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The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction.These organs are located on the outside of the body, and within the pelvis.
Ejaculation occurs in two stages, the emission stage and the expulsion stage. [4] The emission stage involves the workings of several structures of the ejaculatory duct; contractions of the prostate gland, the seminal vesicles, the bulbourethral gland and the vas deferens push fluids into the prostatic urethra. [3]
The first fossilized evidence of sexual reproduction in eukaryotes is from the Stenian period, about 1.05 billion years old. [19] [20]Biologists studying evolution propose several explanations for the development of sexual reproduction and its maintenance.
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction.It is initiated by hormonal signals from the brain to the gonads: the ovaries in a female, the testicles in a male.
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction.Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. [1]
is the average number of people infected from one other person. For example, Ebola has an of two, so on average, a person who has Ebola will pass it on to two other people.. In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted (pronounced R nought or R zero), [1] of an infection is the ...
Male infertility refers to a sexually mature male's inability to impregnate a fertile female. [1] Male infertility can wholly or partially account for 40% of infertility among couples who are trying to have children. [2]
Gynecomastia (also spelled gynaecomastia) [a] is the non-cancerous enlargement of one or both breasts in men due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens.