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There are two types of hormones – steroids and peptides. Steroids, made from cholesterol, are largely the sex hormones produced by the adrenal glands or the gonads. Peptides, are chains of amino acids, peptide hormones are also called protein hormones, regulate sleep and sugar concentration.
Hormones are manufactured in the ductless endocrine glands and released into the bloodstream via the capillary network. Hormones work locally (local hormones) or target remote organs or cells (general hormones). Hormones influence the physiology of other cells, the circulation is the main distribution into the body economy.
Endocrines are some of the most vascularized organs of the body. Hormones possess a high degree of chemical activity. A delay from release of hormones to systemic effects can be observed.
Hormones do not act alone, yet form interlocking complexes in the body. No new cellular reactions are created by hormones, merely the rate at which cellular mechanisms operate is regulated.
Hormones are bound to plasma proteins while being transported in the blood and have a direct effect on cellular enzyme systems and permeability of cells.
Homeostasis is managed via the negative feedback cycle, keeping an adequate concentration of hormones, much as a thermostat system, e.g. if the room temperature drops, the heater kicks in.
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