Chapter 8 (Hormones and Sex) Flashcards
cloacal exstrophy
A rare medical condition in which XY individuals are born completely lacking a penis.
hormone
A chemical secreted by an endocrine gland that is conveyed by the bloodstream and regulates target organs or tissues.
endocrine gland
A gland that secrets products into the bloodstream to act on distant targets.
castration
Removal of the gonads, usually the testes.
endocrine
Referring to glands that release chemicals to the interior of the body. These glands secrete the principal hormones used by the body.
synapse
The cellular location at which information is transmitted from a neuron to another cell.
pheromone
A chemical signal that is released outside the body of an animal and affects other members of the same species.
allomone
A chemical signal that is released outside the body by one species and affects the behavior of other species.
protein hormone (peptide hormone)
A hormone that consists of a string of amino acids.
amine hormone
Also called monoamine hormone. A hormone composed of a single amino acid that has been modified into a related molecule, such as melatonin or epinephrine.
steroid hormone
Any of a class of homrones, each of which is composed of four interconnected rings of carbon atoms.
second messenger
A slow-acting substance in a target cell that amplifies the effects of synaptic of hormonal activity and regulates activity within the target cell.
pituitary gland
A small, complex endocrine gland located in a socket at the base of the skull.
pituitary stalk
A thin piece of tissue that connects the pituitary gland to the hypothalamus.
neuroendocrine cell
A neuron that releases hormones into local of systemic circulation.
posterior pituitary
The rear division of the pituitary gland.
oxytocin
A hormone, released from the posterior pituitary, that triggers milk letdown in the nursing female.
arginine vasopressin (AVP) or vasopressin
Also called antidiuretic hormone. A peptide hormone from the posterior pituitary that promotes water conservation and increases blood pressure.
milk letdown reflex
The reflexive release of milk by the mammary glands of a nursing female in response to suckling, or to stimuli associated with suckling.
pair-bond
A durable and exclusive relationship between a male and a female.
negative feedback
The property by which some of the output of a system feeds back to reduce the effect of input signals.
anterior pituitary
The front division of the pituitary gland; it secrets tropic hormones.
tropic hormone
Any of a class of anterior pituitary hormones that affect the secretion of hormones by other endocrine glands.
releasing hormone
Any of a class of hormones, produced in the hypothalamus, that traverse the hypothalamic-pituitary portal system to control the pituitary’s release of tropic hormones.
median eminence
A midline feature on the base of the brain that marks the pont at which the pituitary stalk exits the hypothalamus to connect to the pituitary. The median eminence contains elements of the hypothalamic-pituitary portal system.
hypothalamic-pituitary portal system
An elaborate bed of blood vessels leading from the hypothalamus to the anterior pituitary.
growth hormone (GH)
Also called “somatotropic hormone.” A tropic hormone, secreted by the anterior pituitary, that influences the growth of cells and tissues.
gonad
Any of the sexual organs (ovaries in females, testes in males), which produce gametes for reproduction.
gonadotropin-releasing hormone (GnRH)
A hypothalamic hormone that controls the release of luteinizing hormone and follicle-stimulating hormone from the pituitary.
gonadotropin
An anterior pituitary hormone that selectively stimulates the cells of the gonads to produce sex steroids and gametes.
follicle-stimulating hormone (FSH)
A gonadotropin, named for its actions on the ovarian follicles.
follicle
The structure of the ovary that contains immature ova.
luteinizing hormone (LH)
A gonadotropin, named for its stimulatory effects on the ovarian corpora lutea.
corpus luteum
The structure that forms from the collapsed ovarian follicle after ovulation. The corpora lutea are a major source of progesterone.
testes
The male gonads, which produce sperm and androgenic steroid hormones.
testosterone
A hormone, produced by male gonads, that controls a variety of bodily changes that become visible at puberty. One of a class of hormones called androgens.
androgen
Any of a class of hormones that includes testosterone and other male hormones.
ovaries
The female gonads, which produce eggs (ova) for reproduction.
progestin
Any of a major class of steroid hormones that are produced by the ovary, including progesterone.
estrogen
Any of a class of steroid hormones produced by female gonads.
estradiol
The primary type of estrogen that is secreted by the ovary. Its formal name is 17-beta-estradiol.
progesterone
The primary type of progestin that is secreted by the ovary.
ovulatory cycle
The periodic occurrence of ovulation in females.
oral contraceptive
A birth control pill, typically consisting of steroid hormones to prevent ovulation.
sexual attraction
The first step in the mating behavior of many animals, in which animals emit stimuli that attract members of the opposite sex.
appetitive behavior
The second stage of mating behavior; it helps establish or maintain sexual interaction.
proceptive
Referring to a state in which an animal advertises its readiness to mate through species-typical behaviors, such as ear wiggling in the female rat.
copulation
Also called coitus. The sexual act.
intromission
Insertion of the erect penis into the vagina during copulation.
vagina
The opening from the outside of the body to the cervix and uterus in females.
ejaculation
The forceful expulsion of semen from the penis.
semen
A mixture of fluid, including sperm, that is released during ejaculation.
refractory phase
A period following copulation during which an individual cannot recommence copulation.
Coolidge effect
The propensity of an animal that has appeared sexually satisfied with a present partner to resume sexual activity when provided with a new partner.
sexually receptive
Referring to the state in which an individual (in mammals, typically the female) is willing to copulate.
estrus
The period during wich female animals are sexually receptive.
postcopulatory behavior
The final stage in mating behavior. Species-specific postcopulatory behaviors include rolling (in the cat) and grooming (in the rat).
copulatory lock
Reproductive behavior in which the male’s penis swells after ejaculation so that the male and female are forced to remain joined for 5-10 minutes; it occurs in dogs and some rodents, but not in humans.
gamete
A sex cell (sperm or ovum) that contains only unpaired chromosomes and therefore has only half of the usual number of chromosomes.
sperm
The gamete produced by males for the fertilization of eggs (ova).
ovum
An egg, the female gamete.
zygote
The fertilized egg.
ovulation
The production and release of an egg (ovum).
lordosis
A female receptive posture in four-legged animals in which the hindquarter is raised and the tail is turned to one side, facilitating intromission by the male.
activational effect
A temporary change in behavior resulting from the administration of a hormone to an adult animal.
ventromedial hypothalamus (VMH)
A hypothalamic region involved in eating and sexual behaviors.
periaqueductal gray
The region of the midbrain surrounding the cerebral aqueduct that connects the third and fourth ventricles; rich in neuronal cell bodies, it is involved in pain perception and reproductive behaviors.
medial preoptic area (mPOA)
A region of the anterior hypothalamus implicated in the control of many behaviors, including thermoregulation, sexual behavior, and gonadotropin secretion.
vomeronasal organ (VNO)
A collection of specialized receptor cells, near to but separate from the olfactory epithelium, that detect pheromones and send electrical signals to the accessory olfactory bulb in the brain.
medial amygdala
A portion of the amygdala that receives olfactory and pheromonal information.
parental behavior
Behavior of adult animals that has the goal of enhancing the well-being of their own offspring, often at some cost to the parents.
parabiotic
Referring to a surgical preparation that joins two animals to share a single blood supply.
orgasm
The climax of sexual behavior, marked by extremely pleasurable sensations.
phallus
The clitoris or penis.
penis
The male phallus
clitoris
The female phallus
double-blind test
A test of a drug or treatment in which neither the subjects nor the attending researchers know which subjects are receiving the drug (treatment) and which are receiving the placebo (control).
sexual differentiation
The process by which individuals develop either malelike or femalelike bodies and behavior.
sex determination
The process by which it is established that a fetus will develop as a male or a female.
indifferent gonads
The undifferentiated gonads of the early mammalian fetus, which will eventually develop into either tests or ovaries.
SRY gene
A gene on the Y chromosome that directs the developing gonads to become testes. The name SRY stands for sex-determining region on the Y chromosome.
genital tubercle
In the early fetus, a “bump” between teh legs that can develop into either a clitoris or a penis.
wolffian duct
A duct system in the embryo that will develop into male reproductive structures (epididymis, vas deferens, and seminal vesicles) if tests are present in the embryo.
müllerian duct
A duct system in the embryo that will develop into female reproductive structures (oviduct, uterus, and upper vagina) if testes are not present in the embryo.
anti-müllerian hormone (AMH)
Also called “müllerian regression hormone.” A protein hormone secreted by the fetal testes that inhibits müllerian duct development.
dihydrotestosterone (DHT)
The 5-alpha-reduced metabolite of testosterone; DHT is a potent androgen that is principally responsible for the masculinization of the external genitalia in mammalian sexual differentiation.
5-alpha-reductase
An enzyme that coverts testosterone into dihydrotestosterone.
Turner’s syndrome
A condition, seen in individuals carrying a single X chromosome but no other sex chromosome, in which an apparent female has underdeveloped but recognizable ovaries.
congenital adrenal hyperplasia (CAH)
Any of several genetic mutations that can cause a female fetus to be exposed to adrenal androgens, resulting in partial masculinization at birth.
intersex
Referring to an individual with atypical genital development and sexual differentiation that generally resembles a form intermediate between typical male and typical female genitals.
androgen insensitivity syndrome (AIS)
A syndrome caused by a mutation of teh androgen receptor gene that renders tissues insensitive to androgenic hormones like testosterone. Affected XY individuals are phenotypic females, by they have internal testes and regressed internal genital structures.
quevedoces
Literally, “eggs at 12” (in Spanish). A nickname for individuals who are raised as girls but at puberty change appearance and begin behaving as boys.
organizational effect
A permanent alteration of the nervous system, and thus permanent change in behavior, resulting from the action of a steroid hormone on an animal early in its development.
sensitive period
The period during development in which an organism can be permanently altered by a particular experience or treatment.
neonatal
Referring to newborns.
Sexual dimorphism
The condition in which males and females of the same species show pronounced sex differences in appearance.
sexually dimorphic nucleus of the pre-optic area (SDN-POA)
A region of the preoptic area that is five to six times larger in volume in male rats than in females.
spinal nucleus of the bulbocavernosus (SNB)
A group of motoneurons in the spinal cord of rats that innervate striated muscles controlling the penis.
Onuf’s nucleus
The human homolog of the spinal nucleus of the bulbocavernosus (SNB) in rats.
fraternal birth order effect
A phenomenon in human populations, such that the more older biological brothers a boy has, the more likely he is to develop a homosexual orientation.
