Chemical and electrical coordination 2

The endocrine system is adapted to carry information from one source to many destinations to bring about long lasting responese
The endocrine system consists of a number of glands that secrete hormones (organic chemicals, usually proteins or steriods). the glands of the endocrine system are called endocrine glands or ductless glands because they secrete their hormones directly into the bloodstream
Each hormone has its own target cells on which it acts. Therefore, although all the hormones are transported together in the bloodstream, each has its own specific effect on the body
Endocrine glands occur at strategic points around the body. Their hormones regualte a wide range of activities, including blood glucos concentration, gastric secretion, heart rate, metabolism, growth rate, reproduction, and water balance.
Local and chemical mediators. The nervous and endocrine systems are not the only means of coordination in a multicellular organism. There are many local chemical mediators that affect only cells in theor immediate vicinity. Two such chemical mediators are histamine and prostaglandis
Histamine is part of the mammalian non-specific immune system. It is produced by white blood cells and most cells when the skin is irrated by a foriegn substance such as poison from a stinging nettle. Release of histamine into the vicintiy of the irratation causes an accute inflamation involving pain, heat, redness, swelling, and sometimes loss of function of theaafected par. Antihistamines act by inhibiting the action of histmaine
Prostaglandis are modified fatty acids, often derived from plasma membranes. They were first discovered in compoents of the seamen produced byt he human prostate gland. In seamen, prostaglandis stimulate concentration of the uterine wall, helping to convey sperm to the egg. They have another reprodcutive function. When secreted by cells in walls of the plasma, they make nearby muscles of the uterus more excitable, helping to induce labour during childbirth
Their more general function is as local regulators in the mammalian defence system. During a viral or bacterial infection or after a physical trauma, various prostaglandis help induce fever and inflamation and also intensity feelings of pain. These unpleasent effects acts as an alarm, informing the organisms that something is wrong. Ibuprofen and asprin inhibit the secretion of prostaglandis

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Chemical and electrical coordination 2

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	Criado por harry_bygraves mais de 11 anos atrás