Chapter_8_Book

Cloacal exstrophy

A rare medical condition in which individuals are born with an incompletely sealed lower abdomen.

Hormone

A chemical, usually secreted by an endocrine gland, that is conveyed by the bloodstream and regulates target organs or tissues.

Endocrine gland

A gland that secretes hormones into the bloodstream to act on distant targets.

Castration

Removal of the gonads, usually the testes.

Peptide hormone

A hormone that consists of a string of amino acids.

Amine 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 hormones, each composed of four interconnected rings of carbon atoms.

Second messenger

A slow-acting substance in a target cell that amplifies the effects of synaptic or hormonal activity and regulates activity within the target cell.

Immunocytochemistry (ICC)

A method for detecting a particular protein in tissues, where an antibody recognizes and binds to the protein and chemical methods are used to leave a visible reaction product around each antibody.

In situ hybridization

A method for detecting particular RNA transcripts in tissue sections by providing a nucleotide probe that is complementary to, and will hybridize with, the transcript of interest.

Pituitary gland

A small, complex endocrine gland located in a socket at the base of the skull.

Vasopressin

A peptide hormone from the posterior pituitary that promotes water conservation and increases blood pressure.

Oxytocin

A peptide hormone, released from the posterior pituitary, that triggers milk letdown in nursing females and is also associated with various behaviors.

Negative feedback

The property by which some output of a system feeds back to reduce the effect of input signals.

Tropic hormone

A class of anterior pituitary hormones that affect the secretion of hormones by other endocrine glands.

Gonadotropin-releasing hormone (GnRH)

A hypothalamic hormone that controls the release of luteinizing hormone and follicle-stimulating hormone from the pituitary.

Follicle-stimulating hormone (FSH)

A gonadotropin that stimulates the growth and maturation of ovarian follicles and sperm production in males.

Luteinizing hormone (LH)

A gonadotropin that stimulates ovulation and the production of testosterone in males.

Sexual dimorphism

The condition in which males and females of the same species show pronounced sex differences in appearance.

Androgen insensitivity syndrome (AIS)

A syndrome caused by an androgen receptor gene mutation that renders tissues insensitive to androgenic hormones, resulting in XY individuals being phenotypic females with internal testes.

Guevedoces

Individuals born as girls but who develop male external genitalia at puberty due to a mutation in the 5-alpha-reductase gene.

Fraternal birth order effect

The phenomenon in which men with older biological brothers are statistically more likely to be gay.

Organizational effect

A permanent alteration of the nervous system and behavior resulting from the action of a steroid hormone on an animal early in its development.

Sensitive period

The time during development when an organism can be permanently altered by a particular experience or treatment.

Sexual differentiation

The process by which individuals develop either male-like or female-like bodies and behaviors.