Compléter The Endocrine System-Characteristics of HormonesVersion en ligne This game will help retain information about the characteristics of hormones. par Leah Lloyd 1 Each hormone produced in the body is . Each one is different in its chemical composition , structure , and . Despite the differences , there are similarities in these . Chemically , hormones may be classified as either or . All of the hormones and those from the adrenal , are proteins or protein derivatives . This means that their fundamental building blocks are acids . Protein hormones must be administered because they are quickly inactivated by the acid and the stomach . These hormones must be administered by injection . Sex hormones and those from the adrenal cortex are , which are lipid derivatives . These lipid - soluble hormones may be taken orally . 2 Hormones are carried by the throughout the entire body , yet they affect only cells . The specific cells that respond to a given hormone have sites for that hormone . This is sort of a lock - and - key mechanism . If the key fits the lock , then the door will open . If a hormone fits the receptor site , then there will be an . If a hormone and a receptor site do not match , then there is no . All the cells that have receptor sites for a given hormone make up the tissues for that hormone . In some cases , the target tissue is in a single gland or organ . In other cases , the target tissue is diffuse and throughout the body so that many areas are . Hormones bring about their characteristic effects on target cells by cellular activity . Receptor sites may be located on the of the cell membrane to in the of the cell . 3 are very potent substances , which means that they are very small amounts of a hormone may have profound effects on processes . Because of their potency , hormones secretion must be regulated within very narrow limits to maintain in the body . Many hormones are controlled by some form of a feedback mechanism . In this type of system , a gland is to the concentration of a substance that it regulates . A negative feedback system causes a reversal of increases and in body conditions to maintain a state of stability or homeostasis . Some endocrine glands secrete hormones in response to other . The hormones that cause secretion of other hormones are called hormones . A hormone from gland " A " causes gland " B " to its hormone . For example , thyroid - stimulating hormone from the pituitary gland causes the thyroid gland to secrete the hormone . A third method of regulating hormone secretion is by direct stimulation . A nerve causes a gland to secrete its hormone . A physiological example of the mechanism is the sympathetic nervous stimulation of the adrenal , which responds by secreting epinephrine ( adrenaline . )
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