Chapter 5: Sex hormones, sexual differentiation, and the menstrual cycle Flashcards
Prenatal period
The time from conception to birth.
Hormones
Chemical substances secreted by the endocrine glands into the bloodstream.
Testosterone
A hormone secreted by the testes in males (and also present at lower levels in females).
Androgens
A group of sex hormones, one of which is testosterone.
Estrogens
A group of sex hormones, one of which is estradiol.
Progesterone
A sex hormone secreted by the ovaries as well as the testes.
Pituitary gland
A small endocrine gland located on the lower side of the brain below the hypothalamus; the pituitary is important in regulating levels of sex hormones.
Hypothalamus
A small region of the brain that is important in regulating many body functions, including the functioning of the sex hormones.
Follicle-stimulating hormone (FSH)
A hormone secreted by the pituitary; it stimulates follicle development in females and sperm production in males.
Luteinizing hormone (LH)
A hormone secreted by the pituitary; it regulates estrogen secretion and ovum development in females and testosterone production in males.
GnRH (gonadotropin-releasing hormone)
A hormone secreted by the hypothalamus that regulates the pituitary’s secretion of gonad-stimulating hormones.
HPG axus
Hypothalamus-pituitary-gonad axis, the negative feedback loop that regulates sex-hormone production.
Inhibin
A hormone secreted by the testes and ovaries that regulated FSH levels.
Prolactin
A pituitary hormone that stimulates milk production by the mammary glands.
Oxycotin
A pituitary hormone that stimulates milk ejection from the niplpes and contractions of the uterus during childbirth.
SRY
Stands for sex-determining region, Y chromosome.
Müllerian ducts
Ducts (kanalen) found in both male and female fetuses; in males they degenerate, and in females they develop into the fallopian tubes, the uterus and the upper part of the vagina.
Wolffian ducts
Ducts (kanalen) found in both male and female fetuses; in females they degenerate, and in males they develop into the epididymis, the vas deferens, and the ejaculatory duct.
Cryptochidism
Undescended testes; the condition in which the testes do not descend to the scrotum as they should during prenatal development.
Endocrine disrupters
Chemicals in the environment that affect the endocrine system and cause adverse effects on animals, including humans.
Epigenetics
A functional change to DNA that does not alter the genetic code itself but leads to changes in gene expression. often an epigenetic change involves methylation, that is, a methyl group is attached to the base cytosine in the DNA.
Homologous organs
Organs in the male and female that develop from the same embryonic tissue.
Analogous organs
Organs in the male and female that have similar functions.
Intersex
A condition in which the individual has a mixture of male and female reproductive structures, so that it is not clear at birth whether the individual is male or female. Formerly called a pseudohermaphrodite.