Estrous and Menstrual Cycles

These flashcards provide terminology and definitions related to estrous and menstrual cycles, which are essential for understanding reproductive biology.

Estrous Cycle

The reproductive cycle characterized by distinct phases regulated by hormones, observed in most mammals.

Polyestrus

A reproductive cycle occurring multiple times throughout the year, seen in animals like pigs and cows.

Monoestrus

A reproductive cycle characterized by a single period of estrus per breeding season, found in dogs.

Proestrus

The phase prior to estrus where rapid follicle growth occurs, leading to increased estrogen production.

Estrus

The period of sexual receptivity in females, characterized by ovulation and heightened estrogen levels.

Metestrus

The phase following ovulation characterized by the formation of the corpus hemorrhagicum.

Diestrus

The luteal phase following ovulation, predominantly influenced by elevated progesterone levels.

Follicle Phase

The stage in the estrous cycle characterized by follicle growth and estrogen dominance.

Luteal Phase

The stage following ovulation where the corpus luteum forms and progesterone levels rise.

Amenorrhea

The absence of menstruation, often associated with significant hormonal changes.

GnRH

Gonadotropin-releasing hormone that stimulates the release of reproductive hormones.

Ovulation

The release of an egg from the ovary, a critical event of the estrous and menstrual cycles.

Menstrual Cycle

The reproductive cycle in primates, including humans, characterized by menstruation and a series of hormonal changes.

Corpus Luteum

The structure formed from the follicle post-ovulation, critical for progesterone production.

Follicle Stimulating Hormone (FSH)

A hormone involved in the regulation of the reproductive cycle; its elevated levels can indicate menopause.

Estrous Behavior

Specific behaviors exhibited by females during estrus, such as increased receptivity to mating.

Seasonally Polyestrus

Reproductive cycles that are influenced by seasonal factors, seen in some domestic and wild animals.

Luteolysis

The regression of the corpus luteum leading to a decrease in progesterone levels.

Endometrium

The inner lining of the uterus that undergoes cyclic changes during the menstrual cycle.

Ovulation Cycle Length

Refers to the number of days between key markers of reproductive cycles, varying among species.