The nervous system sends electricalmessages to control and coordinatethe body. The endocrine systemhas a similar job, but useschemicals to “communicate”. Thesechemicals are known as hormones.
A hormone is a specific messengermolecule synthesized and secretedby a group of specialized cellscalled an endocrine gland.
These glands are ductless, whichmeans that their secretions(hormones) are released directlyinto the bloodstream and travel toelsewhere in the body to targetorgans, upon which they act.
The pituitary gland is just the size of apea. It hangs from the hypothalamus.-most important endocrine gland-produces growth hormone: whichstimulates cell division and the growth ofmuscles and bones-other hormones it produces stimulateand control other glands
The pituitary gland is called the “mastergland” but it is under the control of thehypothalamus. Together, they controlmany other endocrine functions.They secrete a number of hormones,especially several which are important tothe female menstrual cycle, pregnancy,birth, and lactation (milk production).
This gland is located near the centerof the brain in humans, and isstimulated by nerves from the eyes. Thepineal gland secreted melatonin atnight when it’s dark, thus secretes morein winter when the nights are longer.Melatonin promotes sleep (makes youfeel sleepy). Melatonin also affects skinpigmentation.
-located at the base of the neck.-produces thyroxine that controls therate at which the body cells use food torelease energy.-also produces calcitonin: reduces bloodcalcium levels by causing calcium to bedeposited in bones.-helps in regulating body growth anddevelopment
Thyroid hormones regulatemetabolism, therefore body temperatureand weight. The thyroid hormonescontain iodine, which the thyroid needsin order to manufacture these hormones.If a person lacks iodine in his/her diet,the thyroid cannot make the hormones,causing a deficiency.
Parathyroid glands are two-pairs ofpea size glands found near the thyroidgland.The hormone produced by this glandshelp control level of calcium in theblood.
The thymus is located in the upperthorax behind the breast bone andextends below the thyroid gland.The thymus forms part of the body’simmune system by causinglymphocytes(white blood cells) to become T cells –cells which become parts of the body’sdefense against infection.
The adrenal glands are a pair of cone-shaped glands, each on top of thekidneys. They consist of two parts, theouter cortex and the inner medulla.The cortex produces hormones thataffect the body metabolism. The cortexsecretes corticosteroids .
The hormones produced by the adrenalsprepare the body for stress.The medulla secretes epinephrine(adrenaline) and other similarhormones in response to stressors suchas fright, anger, caffeine, or low bloodsugar.
-lies behind the stomach.Scattered throughout the pancreas aretiny glandular tissues called “islets ofLangerhans”– that produceshormones glucagon and insulin.Insulin lowers blood sugar level whileglucagon raises blood sugar levels.
This organ has two functions. It servesas a ducted gland, secretingdigestive enzymes into the smallintestine. The pancreas also serves asa ductless gland in that the islets ofLangerhans secrete insulin andglucagon to regulate the bloodsugar level.
The female ovaries and male testessecretes sex hormones. The secretion ofsex hormones by the gonads is controlled bypituitary gland hormones. Typically maletestes secrete primarily androgens including testosterone. Female ovariesmake estrogen and progesterone invarying amounts depending on where in hercycle a woman is.
Identify the glands being described.1. A gland located at the base of the neck.2. An organ that controls the pituitary gland.3. A gland that secretes epinephrine4. The master gland5. Male sex gland6. Female sex gland7. A gland that lies behind the stomach8. Two-pairs of pea sized glands found near the thyroid9. A gland that is part of the body’s immune system10.Hormone produced by the pineal gland that regulates body’s day and night activities.