reversed definitions ch 12

müllerian ducts

System of tubes in the fetus that will develop into elements of the female internal reproductive tract

Guevedoces

Nickname for individuals that are born with femalelike genitalia but develop into males at puberty

intromission

Insertion of the penis into the vagina

Onuf's nucleus

The motoneuronal nucleus of the human spinal cord that innervates the bulbocavernosus muscle

semen

A mixture of fluids plus sperm

spinal nucleus of the bulbocavernosus

Sexually dimorphic nucleus found in the spinal cord of rats - innervates muscles attached to the base of the penis

refractory period

Span of time following copulation during which no further mating will occur

Coolidge effect

Propensity of an animal ( usually a male ) to resume copulating when provided with a new partner

SDN-POA

Sexually dimorphic nucleus found in the hypothalamus of rats

estrus

Period of sexual receptivity , or " heat , " in many species

copulatory lock

Postcopulatory swelling of the penis that occurs in some species , preventing disengagement of the penis from the vagina

gametes

Collective name for sperm and ova

syrinx

Muscular organ that produces song in birds

A-fetoprotein

Circulating substance that binds to estrogen and prevents it from entering the brain

Turner's syndrome

Disorder in which individuals have only one sex chromosome , an X

aromatization hypothesis

Proposal that testosterone is converted to estradiol in the brain , which then masculinizes the brain via estrogen receptors

aromatase

Enzyme that converts testosterone to estradiol

sexual determination

The first event that determines whether an individual will become a male or a female

lordosis

Stereotyped female copulatory posture of rats and other species

precocial

Born in an advanced , functional state

castration

Surgical removal of the testes

altricical

Born in a helpless , immature state

sensitive period

Time " window " in development during which a hormone can exert its organizing influence

sexual differentiation

The physiological process by which an individual turns into a male or a female

activational effect

Hormonal action in which a physiological or behavioral characteristic may be induced at any time

organizational effect

Permanent alteration determined by the actions of a hormone early in life

androgen insensitivity

Syndrome in which the individual's body fails to respond to endogenous androgens , due to a failure of androgen receptors

congenital adrenal hyperplasia

Disorder in which a female is partially masculinized due to the excessive secretion of adrenal androgens

ovulatory cycle

Period of time from one release of eggs to the next ( about 4 days in rats , about 28 in women )

true hermaphrodites

Individuals that can make both sperm and ova , common among invertebrates

serial hermaphrodites

Category of animals that can switch sexes successively

sexual dimorphism

General term for a characteristic that differs between the two sexes

vomeronasal organ

Accessory olfactory system specialized for detecting pheromones

parthenogenesis

Reproductive system in which females spontaneously give birth to offspring without mating

5-A-reductase

Enzyme that converts testosterone to DHT

dihydrotestosterone

Metabolite of testosterone responsible for stimulating the development of masculine external genitalia

wolffian ducts

System of tubes that eventually develops into elements of the male internal reproductive tract

SRY

Gene whose protein induces the indifferent gonad to differentiate into a testis