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Vagusstoff (literally translated from German as "Vagus Substance") refers to the substance released by stimulation of the vagus nerve which causes a reduction in the heart rate. Discovered in 1921 by physiologist Otto Loewi , vagusstoff was the first confirmation of chemical synaptic transmission and the first neurotransmitter ever discovered.
The female reproductive system likewise contains two main divisions: the external genitalia (the vulva) and the internal genitalia. The ovum meets with the sperm cell : a sperm may penetrate and merge with the egg, fertilizing it with the help of certain hydrolytic enzymes present in the acrosome.
The genetic load of organisms and their populations will increase due to the addition of multiple deleterious mutations and decrease the overall reproductive success and fitness. For sexually reproducing populations, studies have shown that single-celled bottlenecks are beneficial for resisting mutation build-up [ citation needed ] .
The term vagina is from Latin vāgīna, meaning "sheath" or "scabbard". [1] The vagina may also be referred to as the birth canal in the context of pregnancy and childbirth. [2] [3] Although by its dictionary and anatomical definitions, the term vagina refers exclusively to the specific internal structure, it is colloquially used to refer to the vulva or to both the vagina and vulva.
The human female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. The reproductive system is immature at birth and develops at puberty to be able to release matured ova from the ovaries , facilitate their fertilization , and create a protective environment for the ...
In the female, a deep groove forms around the phallus. The sides of it grow dorsalward as the labioscrotal folds, which ultimately form the labia majora in females. The labia minora, in contrast, arise by the continued growth of the lips of the groove on the under surface of the phallus; the remainder of the phallus forms the clitoral glans. [8]
The human female reproductive system is a series of organs primarily located inside the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina, which leads from the vulva , the vaginal opening, to the uterus; the uterus , which ...
As with most things related to the reproductive system, folliculogenesis is controlled by the endocrine system. Five hormones participate in an intricate process of positive and negative feedback to regulate folliculogenesis. They are: gonadotropin-releasing hormone (GnRH) secreted by the hypothalamus; two gonadotropins: