Chapter 6 Flashcards
What is the difference between estruous and menstrual cycle?
Estrous Cycle: The reproductive cycle of most female mammals, during which they experience periods of sexual receptivity (estrus or heat). Unlike humans, animals with an estrous cycle do not menstruate
Menstrual Cycle: Found in primates, including humans, involving cyclic shedding of the uterine lining if pregnancy does not occur.
What are the phases of the estrous cycle?
Proestrus: Period of follicular growth; estrogen levels rise, and the female becomes more attractive to males, often via pheromonal cues in urine and vaginal secretions
Estrus: Female is sexually receptive (heat); ovulation occurs, and mating behavior is observed. Males are strongly attracted due to the release of specific pheromones and changes in vaginal secretions
Diestrus: If fertilization does not occur, the corpus luteum degenerates, and progesterone levels drop
Anestrus: Period of sexual inactivity before the next cycle begin
What are the phase of the menstrual cycle?
Menstrual Phase-> Shedding of the uterine lining occurs if no fertilization happens. Progesterone and estrogen levels are low
Follicular Phase-> Follicles in the ovary mature due to the release of FSH (Follicle-Stimulating Hormone); estrogen levels rise, thickening the uterine lining
Ovulatory Phase: A surge in LH (Luteinizing Hormone) triggers ovulation, releasing a mature egg from the ovary
Luteal Phase: Corpus luteum forms and produces progesterone, which maintains the uterine lining for potential implantation. If no fertilization occurs, progesterone drops, leading to menstruatio
What are the mechanics of copulation in rodents?
Intromission: The male inserts his penis into the female’s vagina, made possible by lordosis
Ejaculation: Occurs after multiple intromissions
Post-Copulatory Behaviors: The female may groom herself or the male, move around the cage, or rest.
What are some female-initiated mating cues in rodents?
Darting: The female quickly approaches and moves away from the male
Ear Wiggling: Rapid movement of ears to signal receptivity
Hopping: Short jumping movements that attract the male’s attentio
What is the cycle duration in canines?
7-8months
What are the species that have postural variation during copulation?
Humans, bonobos, and gorillas display diverse sexual behaviors
What are Beach’s three components of female sexual behavior?
Attractivity: The female’s ability to attract a male
Proceptivity: The female’s active behaviors to initiate mating
Receptivity: The female’s responsiveness to the male’s advances.
Which hormones is responsible for attractivity in females?
estradiol/ estrogen
What is the Coolidge effect?
The Coolidge Effect: Males show reduced interest in a female after repeated mating but remain attracted to novel female
What are some alternative classification systems?
Precopulatory: Attraction and courtship behaviors
Copulatory: Behaviors facilitating successful sperm transfer
Sexual motivation = Drive to seek out partners
Sexual facilitation = Physical response allowing successful copulation
Copulatory: Direct mating actions.
Paracopulatory: Behaviors stimulating male arousal
Progestative: Actions that maximize fertilization success
Which studies are used to satudy sex drive in females?
Motivaltional tests:
- Operant conditioning tasks where females press levers for access to males
- Preference tests where females choose between different mating conditions
What are the different hormones at play in the female reproductive cycle?
Gonadal sex steroid hormones (estrogen, progesterone)
Gonadotropins (FSH, LH)
Hypothalamic releasing hormones (GnRH)
What is the cascade responsible for the female reproductive cycle?
The hypothalamus secretes GnRH in pulses
GnRH stimulates the anterior pituitary to release FSH and LH
FSH and LH stimulate the ovaries to release estrogen and progesterone
High estrogen and progesterone suppress further gonadotropin secretion (negative feedback)
What is the role of kisspeptin in female reproductive cycle?
Kisspeptin cells in the anteroventral periventricular nucleus (AVPV) express estrogen receptors and receive SCN input
- SCN send LH surge and kisspeptin neurons enhance activity of GnRH hormone
What are the key brain regions in the hypothalamus responsible for female sexual behaviour?
Anterior Hypothalamus & Medial Hypothalamus: Lesions reduce proceptive behaviors (e.g., tongue-flicking in marmosets)
VMH (Ventromedial Hypothalamus) & MPOA (Medial Preoptic Area):
- VMH: Excitation linked to proceptive behavior
-MPOA: Inhibition linked to proceptive behavior; excitation linked to copulation
What are the brain regions and hormones in female orgasm?
Orgasm activates hypothalamus, periaqueductal gray, hippocampus, cerebellum
Self-stimulation of genital areas activates the paracentral lobule (sensory cortex)
- Testosterone: Linked to relaxing, peaceful orgasm experiences
- Estradiol: Correlated with physical orgasm sensations.
What are the sex differences in neural activation when presented with erotic stimuli?
Amygdala & Hypothalamus: Higher activation in men
Ventral Striatum: Similar activation in both sexes (reward processing)
