Chapter 35

hypothalamo-hypophysical portal system

A system of blood vessels in a vertebrate that connects capillaries in the hypothalamus to capillaries in the anterior pituitary,providing a direct pathway by which hypothalamic hormones can reach specific populations of cells in the adenohypophysis (anterior pituitary)

estrogens

A group of sex hormones found more abundantly in females than males. They are responsible for female sexual maturation and other functions.

progesterone

A hormone produced by the ovaries which acts with estrogen to bring about the menstral cycle. Primary hormone during pregnancy.

follicle-stimulating hormone (FSH)

A hormone released by the pituitary gland that stimulates the production of sperm in the male and growth of the follicle (which produces the egg) in the female.

oxytocin

A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.

neurosecretory cells

A specialized nerve cell that releases a hormone into the bloodstream in response to signals from other nerve cells; located in the hypothalamus and adrenal medulla.

hypothalamus

A structure found near the base of the forebrain that is involved in the regulation of basic biological needs (eating, drinking, body temperature)

steroid hormones

Androgens & estrogens. Diffuse directly through the cell membrane and bind to a receptor inside the nucleus that triggers the cell's response.

gonadotropins

Anterior pituitary topic hormones FSH (follicle stimulating hormone) and LH (luteinizing homeon) that stimulates the gonads (testes and ovaries) to produce gametes and to secrete sex steroids.

endocrine glands

Glands of the endocrine system that release hormones into the bloodstream

antidiuretic hormone (ADH)

Hormone produced by the neurosecretory cells in the hypothalamus that stimulates water reabsorption from kidney tubule cells into the blood and vasoconstriction of arterioles.

thyroid-stimulating hormone (TSH)

It prompts the thyroid gland in the neck to release thyroxine, which is necessary for brain development and for GH to have its full impact on body size.

anterior pituitary

Makes and secretes its own hormones

adrenocorticotropic hormone (ACTH)

Released from the anterior pituitary gland to target the adrenal cortex. It stimulates the release of hormones involved in stress responses.

luteinizing hormone (LF)

hormone produced by the pituitary gland; promotes ovulation; highest at the menstrual cycle

non-neural endocrine cells

only cells that posses receptor molecules that recognize and bind a sepcific hormone will respond, hormone travel in the blood throughout the body

neurohemal organ

similar to glands, but they store their secretory product in a special chamber until stimulated to release it by a signal from the nervous system (or another hormone)

releasing hormones (RH)

stimulate the anterior pituitary to release hormones

amine hormones

synthesized from the amino acid tyrosine, some are water soluble and some are lipid soluble

gonadotropin-releasing hormone (GnRH)

the hypothalamic releasing hormone that controls the release of the two gonadotropic hormones from the anterior pituitary

tropic hormones

hormones that stimulate other glands to release their hormones

androgens

A class of sex hormones secreted by the gonads, found in both sexes, but in higher levels among males than females following puberty.

target cell

Cells with specific receptors in their membranes to accept specific hormones.

hormone

Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.

pheromones

Chemical signals released by an animal that communicate information and affect the behavior of other animals of the same species.

pituitary gland

Endocrine gland attached to the base of the brain that secretes hormones that affect the function of other glands as well as hormones that act directly on physical processes.

posterior pituitary

Extension of the hypothalamus; does not make its own hormones, only stores and releases the hormones made by the hypothalamus

growth hormone (GH)

an anabolic hormone that has both metaboilc and growth-promoting actions

endocrine cells

cells that secrete endocrine signals

tropins

hormones that regulate other endocrine glands or tissues

peptide and protein hormones

large molecules that are easily transported in blood; released by exocytosis and most hormones are peptides

inhibiting hormones (IH)

prevent the synthesis and secretion of pituitary hormones. The hormones released by the anterior pituitary gland controls other endocrine glands.