Reproductive Behavior

Vocabulary-style flashcards covering key terms and their definitions from the notes on reproductive behavior.

Sex (biological)

Biological status determined by chromosomes, gonads, and hormonal milieu (e.g., typical male XXY/XY patterns and associated development).

Gender

Identity and behaviors that may align with or differ from biological sex; a social/psychological construct.

Organizational effects

Permanent effects of early hormone exposure on tissue differentiation (brain, reproductive organs).

Activational effects

Temporary effects of hormones that activate certain physiological or behavioral processes in puberty or adulthood.

Gonads

Testes or ovaries; primary sources of sex hormones and gametes.

Internal sex organs

Embryonic derivatives such as Müllerian (female) and Wolffian (male) systems that form internal reproductive structures.

External sex organs

Genitalia such as penis, scrotum, clitoris, and vagina.

SRY gene

Sex-determining region of the Y chromosome; its presence initiates testis development.

Anti-Müllerian Hormone (AMH)

Hormone from fetal testes that inhibits the Müllerian system (defeminizing effect).

Androgens

Male hormones (e.g., testosterone) that masculinize development and promote Wolffian system formation.

Testosterone

Primary androgen; drives male development and secondary sex characteristics; precursor to DHT.

Dihydrotestosterone (DHT)

Potent androgen derived from testosterone; essential for external male genitalia development.

Turner’s syndrome

XO karyotype; typically female; often lacks functional ovaries and certain hormones.

Androgen insensitivity syndrome (AIS)

XY individual with testes but androgen insensitivity; external female or ambiguous genitalia; deficient masculinization.

Persistent Müllerian duct syndrome (PMDS)

XY individual with retention of Müllerian (female) internal structures despite androgen exposure.

Müllerian system

Embryonic precursors to female internal organs: fimbria, fallopian tubes, uterus, upper vagina.

Wolffian system

Embryonic precursors to male internal organs: epididymis, vas deferens, seminal vesicles.

Default female development

In absence of masculinizing hormones from testes, development tends toward female structures.

Sexual maturation

Pubertal development including the emergence of secondary sex characteristics and reproductive capability.

Secondary sexual characteristics

Physical features that distinguish sexes after puberty (e.g., breasts, facial hair, voice changes).

Gonadotropin-Releasing Hormone (GnRH)

Hypothalamic hormone that stimulates anterior pituitary to release FSH and LH.

Follicle-Stimulating Hormone (FSH)

Pituitary hormone that stimulates gamete production and ovarian follicle growth.

Luteinizing Hormone (LH)

Pituitary hormone that triggers ovulation and stimulates sex steroid production.

Kisspeptin

Neuropeptide that triggers GnRH release from the hypothalamus.

Estradiol

Major ovarian estrogen; promotes female development and regulates the menstrual cycle.

Puberty

Developmental stage marked by activation of the HPG axis and onset of reproductive capability.

Menstrual cycle

Monthly cycle in humans; endometrium thickens and sheds; ovulation occurs mid-cycle.

Estrous cycle

Reproductive cycle in non-primate mammals; endometrium reabsorbed if no pregnancy; mating linked to ovulation.

Endometrium

Uterine lining that thickens during the cycle and is shed if no pregnancy.

Corpus luteum

Rise from the ruptured follicle after ovulation; secretes estrogen and progesterone to maintain lining.

Progesterone

Hormone that maintains the uterine lining and supports early pregnancy.

Estrogen

Group of hormones (including estradiol) defining female sex characteristics and reproductive function.

Prolactin

Pituitary hormone essential for milk production and maternal behavior.

Maternal behavior

Behaviors such as nursing, licking, and grooming; modulated by MPOA and olfactory cues.

Medial preoptic area (MPA/POA)

Brain region critical for male sexual behavior and maternal behavior; integrates hormonal signals.

Ventromedial Hypothalamus (VMH)

Brain region linked to female sexual behavior and aggression; activity influences mating and other behaviors.

Medial amygdala

Brain region involved in processing pheromonal cues and social/sexual stimuli.

Periaqueductal Gray (PAG)

Midbrain structure involved in defensive and mating behaviors; part of sexual behavior circuits.

Fos protein

Protein used as a marker of neuronal activation after a behavior or stimulus.

Pheromones

Chemical signals that affect social/ reproductive behaviors; detected by the vomeronasal system.

Vomeronasal organ

Sensory organ for pheromones that projects to the amygdala and hypothalamus.

Optogenetics

Technique to control neuron activity with light using light-sensitive proteins.

Channelrhodopsin

Light-activated cation channel used to excite neurons in optogenetics.

Halorhodopsin

Light-driven chloride pump used to inhibit neurons in optogenetics.

Dopamine reward circuitry

Neural pathways that mediate motivation and reward, implicated in maternal and other behaviors.

Sexual orientation

Pattern of sexual attraction toward others; influenced by biology and experience.

Sexually dimorphic nuclei

Brain regions that differ between sexes and underlie behavioral differences.

See-saw control of mating and aggression

Balance where VMH activity modulates aggression in males and must be inhibited to allow mating.

Nucleus paragigantocellularis (nPGi)

Brainstem region that inhibits the spinal ejaculation generator via serotonin.

Lumbar spinothalamic tract (LSt)

Spinal network involved in ejaculation control.

Erection vs ejaculation control

Differentiated neural pathways; ejaculation often regulated by nPGi-LSt circuitry.