Biology: Chapter 45
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loverlylaur on April 2, 2009
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96 terms
Terms | Definitions |
|---|---|
 hormone | one of many types of circulating chemical signals that are formed in specialized cells, travel in body fluids, and act on specific target cells to change their functioning |
| endocrine system | internal system of chemical communication involving hormones, the ductless glands that secrete hormones, and the molecular receptors on or in target cells that respond to hormones; functions in concert with the nervous system to effect internal regulation and maintain homeostasis |
| endocrine gland | ductless gland that secretes hormones directly into the bloodstream |
| neurosecretory cells | hypothalamus cells that receive signals from other nerve cells, but instead of signaling to an adjacent nerve cell or muscle, they release hormones into the bloodstream |
| neurohormone | any hormone produced by neurosecretory cells |
| receptor | detects a stimulus; also known as a sensor |
| sensor | detects a stimulus; also known as a receptor |
| control center | receives information from the receptor |
| effector | a molecule that binds to a protein and thereby alters the activity of that protein |
| efferent signal | nerve impulses carried away from the central nervous system to effectors such as muscles or glands |
| negative feedback | primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation |
| reception | occurs when the signal molecule binds to a specific receptor protein in or on the target cell |
| signal transduction | any process by which a cell converts one kind of signal or stimulus into another |
| response | change in the cell's behavior |
| signal transduction pathway | mechanism linking a mechanical or chemical stimulus to a specific cellular response |
| cytokines | In the vertebrate immune system, protein factors secreted by macrophages and helper T cells as regulators of neighboring cells |
| growth factor | protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells; a local regulator that acts on nearby cells to stimulate cell proliferation and differentiation |
| nitric oxide (NO) | local regulator gas produced by many types of cells |
| prostaglandins (PGs) | one of a group of modified fatty acids secreted by virtually all tissues and performing a wide variety of functions as local regulators |
| oxytocin, antidiuretic hormone | hormones released by the posterior pituitary |
| growth hormone, prolactin, FSH, LH, TSH, ACTH | hormones released by the anterior pituitary |
| T3, T4, Calcitonin | hormones released by the thyroid glands |
| T3 and T4 | stimulate and maintain metabolic processes |
| calcitonin | lowers blood calcium level |
| parathyroid hormone | hormone released by the parathyroid glands |
| parathyroid hormone | raises blood calcium level |
| insulin, glucagon | hormones released by the pancreas |
| insulin | lowers blood glucose level |
| glucagon | raises blood glucose level |
| epinephrine, norepinephrine | hormones released by the adrenal medulla |
| glucocorticoids, mineralocorticoids | hormones released by the adrenal cortex |
| epinephrine and norepinephrine | raise blood glucose levels, increase metabolic activities, constrict certain blood vessels |
| glucocorticoids | raise blood glucose level |
| mineralocorticoids | promote reabsorption of Na+ and excretion of K+ in kidneys |
| androgens | hormones released by the testes |
| estrogens, progesterone | hormones released by the ovaries |
| androgens | support sperm formation; promote development and maintenance of male secondary sex characteristics |
| estrogens | stimulate uterine lining growth; promote development and maintenance of female secondary sex characteristics |
| progesterone | promotes uterine lining growth |
| melatonin | hormone released by the pineal gland |
| melatonin | involved in biological rhythms |
| hypothalamus | ventral part of the vertebrate forebrain; functions in maintaining homeostasis, especially in coordinating the endocrine and nervous systems; secretes hormones of the posterior pituitary and releasing factors that regulate the anterior pituitary |
| pituitary gland | endocrine gland at the base of the hypothalamus; consists of a posterior lobe (neurohypophysis), which stores and releases two hormones produced by the hypothalamus, and an anterior lobe (adenohypophysis), which produces and secretes many hormones that regulate diverse body functions |
| posterior pituitary | an extension of the hypothalamus composed of nervous tissue that secretes oxytocin and antidiscretic hormone made in the hypothalamus; a temporary storage site for these hormones; also called the neurohypophysis |
| neurohypophysis | an extension of the hypothalamus composed of nervous tissue that secretes oxytocin and antidiscretic hormone made in the hypothalamus; a temporary storage site for these hormones; also called the posterior pituitary |
| anterior pituitary | portion of the pituitary that develops from nonneural tissue; consists of endocrine cells that synthesize and secrete several tropic and nontropic hormones; also called the adenohypophysis |
| adenohypophysis | portion of the pituitary that develops from nonneural tissue; consists of endocrine cells that synthesize and secrete several tropic and nontropic hormones; also called the anterior pituitary |
| tropic hormone | hormone that has another endocrine gland as a target |
| antidiuretic hormone | hormone that is part of an elaborate feedback scheme that helps regulate the osmolarity of the blood |
| oxytocin | hormone produced by the hypothalamus and released from the posterior pituitary. It induces contractions of the uterine muscles and causes the mammary glands to eject milk during nursing |
| follicle-stimulating hormone (FSH) | tropic hormone produced and secreted by the anterior pituitary that stimulates the production of eggs by the ovaries and sperm by the testes |
| luteinizing hormone (LH) | protein hormone secreted by the anterior pituitary that stimulates ovulation in females and androgen production in males |
| thyroid-stimulating hormone (TSH) | tropic hormone produced and secreted by the anterior pituitary that regulates the release of thyroid hormones |
| gonadotropins | hormones that stimulate the activities of the testes and ovaries; a collective term for follicle-stimulating and luteinizing hormones |
| adrenocorticotropic hormone (ACTH) | tropic hormone produced and secreted by the anterior pituitary that stimulates the production and secretion of steroid hormones by the adrenal cortex |
| prolactin (PRL) | hormone produced by the anterior pituitary gland with a great diversity of effects in different vertebrate species |
| melanocyte-stimulating hormone | hormone produced and secreted by the anterior pituitary that regulates the activity of pigment-containing cells in the skin of some vertebrates |
| endorphin | Any of several hormones produced in the brain and anterior pituitary that inhibits pain perception |
| growth hormone (GH) | protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells; a local regulator that acts on nearby cells to stimulate cell proliferation and differentiation |
| insulinlike growth factors (IGFs) | group of peptides produced by the liver, it circulates in blood plasma and directly stimulates bone and cartilage growth |
| thyroid gland | endocrine gland, located on the ventral surface of the trachea, that secretes two iodine-containing hormones, triiodothyronine (T3) and thyroxine (T4), and cacitonin |
| triiodothyronine | the first of two iodine-containing hormones that are secreted by the thyroid gland and help regulate metabolism, development, and maturation in vertebrates |
| thyroxine | the second of two iodine-containing hormones that are secreted by the thyroid gland and help regulate metabolism, development, and maturation in vertebrates |
| T3 | triiodothyronine |
| T4 | thyroxine |
| parathyroid hormone | hormone secreted by the parathyroid glands that raises blood calcium level by promoting calcium release from bone and calcium retention by the kidneys |
| parathyroid glands | four endocrine glands, embedded in the surface of the thyroid gland, that secrete parathyroid hormone and raise blood calcium levels |
| vitamin D | one of the fat-soluble vitamins. The active form functions as a hormone, acting in concert with parathyroid hormone in bone and promoting the uptake of calcium from food within the intestines |
| calcitonin | hormone secreted by the thyroid gland that lowers blood calcium levels by promoting calcium deposition in bone and calcium excretion from the kidneys |
| pancreas | gland with dual functions: The nonendocrine portion secretes digestive enzymes and an alkaline solution into the small intestine via a duct; the endocrine portion secretes the hormones insulin and glucagon into the blood |
| islets of Langerhans | Clusters of endocrine cells within the pancreas that produce and secrete the hormones glucagon (alpha cells) and insulin (beta cells) |
| glucagon | hormone secreted by pancreatic alpha cells that raises blood glucose levels. It promotes glycogen breakdown and release of glucose by the liver |
| insulin | hormone secreted by pancreatic beta cells that lowers blood glucose levels. It promotes the uptake of glucose by most body cells and the synthesis and storage of glycogen in the liver and also stimulates protein and fat synthesis |
| alpha cells | cells in the pancreas that produce glucagon |
| beta cells | cells in the pancreas that produce insulin |
| diabetes mellitus | endocrine disorder marked by inability to maintain glucose homeostasis |
| Type I diabetes mellitus | insulin-dependent diabetes |
| Type II diabetes mellitus | non-insulin-dependent diabetes |
| adrenal gland | one of two endocrine glands located adjacent to the kidneys in mammals. Endocrine cells in the outer portion (cortex) respond to ACTH by secreting steroid hormones that help maintain homeostasis during long-term stress. Neurosecretory cells in the central portion (medulla) secrete epinephrine and norepinephrine in response to nervous inputs triggered by short-term stress |
| adrenal cortex | outer portion of the adrenal glands |
| adrenal medulla | center portion of the adrenal glands |
| epinephrine | catecholamine hormone secreted from the adrenal medulla that mediates fight-or-flightresponses to short-term stress; also functions as a neurotransmitter |
| norepinephrine | hormone that is chemically and functionally similar to epinephrine |
| catecholamines | class of compounds, including epinephrine and norepinephrine, that are synthesized from the amino acid tyrosine |
| corticosteroids | family of steroids synthesized by and released from the adrenal cortex |
| glucocorticoid | steroid hormone secreted by the adrenal cortex that influences glucose metabolism and immune function |
| mineralocorticoids | steroid hormone secreted by the adrenal cortex that regulates salt and water homeostasis. |
| androgens | principal male steroid hormones, such as testosterone, which stimulate the development and maintenance of the male reproductive system and secondary sex characteristics |
| testosterone | most abundant androgen hormone in the male body |
| estrogens | primary female steroid sex hormones, which are produced in the ovary by the developing follicle during the first half of the cycle and in smaller quantities by the corpus luteum during the second half. Estrogens stimulate the development and maintenance of the female reproductive system and secondary sex characteristics |
| progestins | one of a family of steroid hormones, including progesterone, that prepare the uterus for pregnancy |
| pineal gland | small gland on the dorsal surface of the vertebrate forebrain that secretes the hormone melatonin |
| melatonin | hormone secreted by the pineal gland that regulates body functions related to seasonal day length |
| brain hormone | hormone, produced by neurosecretory cells in the insect brain, that promotes development by stimulating the prothoracic glands to secrete ecdysone |
| ecdysone | promotes molting and the development of adult characteristics, as in the change from a caterpillar to a butterfly |
| juvenile hormone | hormone in arthropods, secreted by the corpora allata glands, that promotes the retention of larval characteristics |
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