UNIT 9: ENDOCRINESYSTEM(CHEMICALCOORDINATION)(MADER, 2010: CHAPTER 40 p. 736 –752)
ENDOCRINE GLANDS The nervous system and theendocrine system work together To regulate the activities of the othersystems in the body. Both systems use chemical signalswhen they respond to changes. But they have different means ofdelivering the signals
Differences between the CNS andthe endocrine systemCentral nervoussystemEndocrine systemTransmits electricalimpulsesTransmits chemicalbiological messengersImpulse send throughneurons throughneurotransmittersTransmits messagethrough bloodstreamby means of hormonesFast reaction Slow reactionReaction doesn’t last along timeReaction lasts a longtime
ENDOCRINE GLANDS Endocrine system consist of different endocrineglands in the body. Endocrine glands are ductless . And produce and secrete hormones. That are transported through the blood in the bloodvessels of the body. Towards a specific target organ where it has a specificfunction. The target cells only respond to specific hormonessecreted by specific endocrine glands. If the cell can respond to the hormone, the hormoneand the recepter proteins bind together as a key fits into
EXOCRINE GLANDS Exocrine glands have ducts andsecrete chemicals like enzymes intothese ducts which takes it to thelumen of organs or to the outside ofthe body.
• Hormones are biological chemical messengersthat help cells, body parts and even individuals tocommunicate with one another.• Most hormones are proteins, but the steroids arefats.• Hormones can inhibit or stimulate a reaction.• Hormones are temperature, pH and substratesensitiveHORMONES (CHEMICALSIGNALS)
HYPOTHALAMUS ANDPITUITARY GLAND The hypothalamus controls the glandularsecretions of the pituitary gland (hypophysis)
HYPOPHYSIS Attached to a stalk onto the hypothalamus. Consist of a posterior- and anterior pituitary. Posterior- produce and secrete the followinghormones: ADH and Oxytocin. Anterior- produce and secete the followinghormones: TSH, ACTH, prolactin, growthhormone, FSH and LH.
Posterior pituitary glandhormones: ADH and Oxytocin ADH: Regulate the water reabsorptionthrough the kidneys by changing thepermeability of the renal tubules. Oxytocin: Stimulates the uterus wall tocontract during the process of giving birth andstimulates milk production during pregnancy.
Growth hormone Promotes skeletal and musculargrowth. It stimulates the rate at whichamino acids enter cells andprotein synthesis occurs. It promotes fat metabolism asopposed to glucose metabolism.
DISORDERS CAUSED BY THEUNDERSECRETION OFGROWTH HORMONE When a too little GHhas been producedduring childhood. Normal proportionsbut small stature. Low blood pressure. Can be rectified byinjecting the child withgrowth hormonePITUITARY DWARFISM
DISORDERS CAUSED BYTHE OVERSECRETION OFGROWTH HORMONE If too much GH havebeen produced duringchildhood. Excessive growth ofmuscles and bones. Usually havediabetes. Much taller thannormalchildren/adults.GIANTISM
Disorder of GH :ACROMEGALY Caused byoverproduction ofGH in adults. Enlargement ofbones in the face,fingers and toes asa person ages.
FEEDBACK MECHANISMSCAUSED BY HORMONE ACTION NEGATIVE FEEDBACK MECHANISM
FSH (follicle stimulatinghormone) and LH Stimulates the gonads (testis and ovaries) toproduce sex hormones and gametes.
THYROID GLAND Located in the neckaround the trachea. Red – high blood volume 2 lobes connected byisthmus. Uses Iodine to producethe hormone thyroxin Thyroxin production isstimulated by TSHsecreted by theHypophysis Also secretes thehormone calcitoninSTRUCTURE OF THYROIDGLAND
FUNCTIONS OF THYROXIN Increase the metabolic rate of a person. No specific target organ, they stimulate allcells of the body to metabolize at a faster rate. Promotes the metabolism of glucose so thatmore energy is released.
DISORDERS OF THE THYROIDGLAND Disorder caused by thelack of Iodine in the diet. Without iodine the thyroidis unable to producethyroxin and continuedanterior pituitarystimulation causes thegland to enlarge. Retarded growthduring infancy. Body is short andstocky with mentalretardationSIMPLE GOITERCONGENITALHYPOTHYROIDISM
Disorder of Thyroid Gland:Exophthalmic goiter This goiter is due to an overactivethyroid gland The eyes of a person protrudesbecause of edema in the eye sockettissue Person is hyperactive, nervous, irritable,suffers from insomnia. Sweat excessively and is heat sensitive. Enlarged thyroid can be surgicallyremoved and treated with radioactiveiodine.
FUNCTIONS OF CALCITONIN Regulates the Calcium level in the blood. Calcitonin brings about the deposit of calciumin the bones when the level of calcium in theblood is too high. When the blood calcium level lowers tonormal, the release of calcitonin by the thyroidis inhibited. This lower level of calcium in the blood,stimulates the release of parathyroidhormone (PTH) by the parathyroid glands.
PARATHYROID GLAND 4 parathyroid glands are located on the thyroid. Secretes the hormone: Parathyroid Hormone(PTH) PTH corrects a low blood calcium level PTH promotes the release of calcium by thebones PTH promotes the reabsorption of calcium fromthe kidneys PTH brings about the activation of Vitamin D.
DISORDERS OF THEPARATHYROID GLAND Insufficient PTHsecreted. Dramatic dropin bloodcalcium levels. The bodyshakes fromcontinuousmusclecontraction The bloodcalcium levelbecomesabnormally high. Bones becomesoft and fragile. Person irritableand prone to getkidney stonesTETANYHYPERPARATHYROIDISM
CALCITONIN AND PTH –ANTAGONISTIC HORMONES These 2 hormones (Calcitonin and PTH) areantagonistic. Both hormones work together regulate theblood calcium level. When the blood calcium level is high – thethyroid gland secretes calcitonin. When the blood calcium level is low – theparathyroid gland releases PTH
ADRENAL GLAND Located ontop of thekidneys. Consist of an inner partthe adrenal medulla andand outer part called theadrenal cortex. The adrenal medullasecretes 2 hormones:adrenalin and nor-adrenalin.STRUCTURE
FUNCTIONS OF ADRENALINAND NOR-ADRENALIN Brings about all the bodily changesthat occur when an individualreacts to an emergency situation. Effect of this hormone is shortterm. Released during fright,anxiousness and anger. Increase heart rate. Increase blood flow and bloodpressure. Muscles absorb glucose for energyto react. More blood (oxygen) to brain. Actions of the digestive systeminhibited. Pupils dilate to observe clearlyADRENALIN and NOR-ADRENALIN
MALFUNCTION OF THEADRENAL CORTEX Bronzing of the skin Excess amount ofACTH. This lead to a buildupof melanin. Excess cortisol inblood Sub-cutaneous fatdeposits.ADDISON DISEASE CUSHING SYNDROME
PANCREAS The pancreas consist ofexocrine tissue with ductsthat produce and releasedigestive juice (pancreaticsap) into the duodenum,and endocrine tissuewithout ducts that secretehormones directly into thebloodstream. The endocrine tissue isknow as the Islets ofLangerhans and it secretestwo hormones: Insulin andglucagon (antagonistichormones).
FUNCTIONS OF INSULIN IN THEPANCREAS If blood sugar (glucose) level is high. Insulin is secreted. Insulin stimulates the uptake of glucose bythe cells (liver, muscle and adipose) In the liver and muscles it is stored asglycogen. Muscle cells break it down for energy. Fat cells convert it to glycerol for the forming offat. Therefore insulin lowers the blood sugar
FUNCTIONS OF GLUCAGON When the blood sugarlevel is low. Glucagon is secretedinto the blood. Glucagon stimulatesthe liver cells toconvert glycogen intoglucose for energyproduction. Therefore glucagonraises the blood sugarlevel.
DIABETES MELLITUS Type 1 Diabetes: Pancreas is notproducing insulin Islets of Langerhansdamaged. Glucose accumulatein blood. Coma results if nottreated with insulininjections. Treatment ofDiabetes: Self study
TESTIS AND OVARIES Testis producetestosterone (male sexhormone) Stimulates theformation of male traitsduring puberty Stimulates oil andsweat glands. Stimulates hairloss(baldness) Ovaries produce estrogenand progesterone (femalesex hormones) Estrogen stimulates growth ofthe uterus and vagina duringpuberty and secondarysexual female traits. Stimulate egg production andpreparation of the uterus forpregnancy. Progesterone prepare theuterus wall for possibleimplantation of an embryo.HORMONES PRODUCED BYTHE TESTISHORMONES PRODUCED BYTHE OVARIES
Effects of testosterone onmalesEffects of estrogen andprogesterone in females