A synthetic compound that acts like a hormone in the body. Published by Houghton Mifflin Company. A chemical substance secreted by an endocrine gland or group of endocrine cells that acts to control or regulate specific physiological processes, including growth, metabolism, and reproduction. Most hormones are secreted by endocrine cells in one part of the body and then transported by the blood to their target site of action in another part, though some hormones act only in the region in which they are secreted.
Many of the principal hormones of vertebrates, such as growth hormone and thyrotropin, are secreted by the pituitary gland, which is in turn regulated by neurohormone secretions of the hypothalamus. Hormones also include the endorphins, androgens, and estrogens.
See more at endocrine gland. A substance that is synthesized by a plant part and acts to control or regulate the growth and development of the plant. The action and effectiveness of a hormone can depend on the hormone's chemical structure, its amount in relation to other hormones that have competing or opposing effects, and the ways in which it interacts with chemical receptors in various plant parts.
Auxins, cytokinins, gibberellins, abscisic acid, and ethylene are plant hormones. A Closer Look Among the most abundant and influential chemicals in the human body are the hormones, found also throughout the entire animal and plant kingdoms. The endocrine glands alone, including the thyroid, pancreas, adrenals, ovaries, and testes, release more than 20 hormones that travel through the bloodstream before arriving at their targeted sites.
The pea-sized pituitary gland, located at the base of the brain below the hypothalamus, is considered the most crucial part of the endocrine system, producing growth hormone and hormones that control other endocrine glands.
Specialized cells of the nervous system also produce hormones. The brain itself releases endorphins, hormones that act as natural painkillers. Hormones impact almost every cell and organ of the human body, regulating mood, growth, tissue function, metabolism, and sexual and reproductive function. Compared to the nervous system, the endocrine system regulates slower processes such as metabolism and cell growth, while the nervous system controls more immediate functions, such as breathing and movement.
The action of hormones is a delicate balancing act, which can be affected by stress, infection, or changes in fluids and minerals in the blood. The pituitary hormones are influenced by a variety of factors, including emotions and fluctuations in light and temperature. You and Your Hormones.
Students Teachers Patients Browse. Human body. Home Hormones. Hormones A hormone is a chemical that is made by specialist cells, usually within an endocrine gland. What is a hormone? Some hormones can be synthesised and used as replacement in glandular deficiencies or as treatment for some cancers. Hormones may be injected, others taken by mouth.
Animal hormones include steroid s, eicosanoid s e. Some hormones are produced synthetically to exert effects similar to natural hormones. Plant hormones, called phytohormones , are hormones produced in plants. Some of the phytohormones are abscisic acid , auxin , ethylene , gibberellin, and cytokinin. Hormones are chemical messengers produced by specialized glands and they were produced by switching on the genes designed to produce them.
This tutorial looks at how genes control the production of hormones within the endocrine system of animals Read More. Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most important in regards to the regulation of growth and development. Know the different hormones of animals in this tutorial Hormones are essential in the regulation of the activity of the various biological systems of the human body.
The inefficiency of any of these hormonal control systems may lead to the improper functioning of the body. In this tutorial, get to know the different classes of hormones, metabolism, mechanism, and control of hormone secretions.
Plants, like animals, produce hormones to regulate plant activities, including growth.
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