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From birth, the ovaries of the human female contain many immature, primordial follicles. These follicles each contain a similarly immature primary oocyte . At puberty , clutches of follicles begin folliculogenesis, entering a growth pattern that ends in ovulation (the process where the oocyte leaves the follicle) or in atresia (death of the ...
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.
Without ovulation, she may enter interestrus, which is the combined stages of diestrus and anestrus, before reentering estrus. With the induction of ovulation, the female becomes pregnant or undergoes a non-pregnant luteal phase, also known as pseudopregnancy. Cats are polyestrous but experience a seasonal anestrus in autumn and late winter. [19]
The "libertine bubble theory" proposes that meiotic sex evolved in proto-eukaryotes to solve a problem that bacteria did not have, namely a large amount of DNA material, occurring in an archaic step of proto-cell formation and genetic exchanges.
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 word "kitten" derives from the Middle English word kitoun, which in turn came from the Old French chitoun or cheton. [1] Juvenile big cats are called "cubs" rather than kittens; either term (but usually more commonly "kitten") may be used for the young of smaller wild felids, such as ocelots, caracals, and lynxes.
The koalas require mating in which the presence of ejaculated semen is needed to stimulate the female to produce a LH surge (which would cause ovulation of a follicle). Unlike many other animals, simply being in the presence of a male koala is not enough to induce ovulation itself, nor is vaginal stimulation on its own sufficient to cause ...
In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth —height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed.