Coordination and response

3.3 role of hormones in humansEndocrine glandsDuctless (no duct or tube) glandsProduce and secrete hormones which diffuse directly into the bloodstreamHormones :Chemicals (organic) secreted by endocrine glands of the endocrine system Serve as chemical messengers which are transported by blood ; cause changes in one or more target organRegulate body processes and are only involved in small amountsHave specific & long lasting effectsEventually removed from the bloodstream & destroyed in the liver & excreted in the urine

Endocrine Glands

Endocrine GlandHormoneFunctionPituitary GlandAntidiuretic hormone (ADH)Stimulates kidneys to reabsorb water from the collecting tubulesFollicle-stimulating hormone (FSH)Stimulates production of mature eggs & spermsLuteinising hormone (LH)Stimulates ovulation & corpus luteum formation in females & production of sex hormones in malesThyroid-stimulating hormone (TSH)Stimulates the synthesis & release of thyroxine from the thyroid glandGrowth hormoneStimulates protein synthesis & growth Endocrine GlandHormoneFunctionThyroid glandThyroxineRegulates the bodys metabolism Helps in normal physical & mental developmentEndocrine GlandHormoneFunctionAdrenal gland

AdrenalineIncreases heart rate, breathing rate, blood pressure, metabolic rate, blood flow to the muscles & glucose level in the bloodAldosteroneRegulates the reabsorption of sodium ions in the kidneyEndocrine GlandHormoneFunctionPancreas

Insulin?Glucagon?Endocrine GlandHormoneFunctionOvaries Estrogen Stimulates the development of eggs & development of female reproductive organs Stimulates the development of secondary sexual characteristicsProgesterone Prepares the uterus for implantation of a developing embryoEndocrine GlandHormoneFunctionTestesTestosterone Stimulates sperm production and development of testes Stimulates development of secondary asexual characteristics in malesRegulation of Hormonal SecretionsSecretion of a hormone may be regulated by:Another hormoneThe level of certain substances (metabolites)The nervous systemRegulation of a hormone by another hormone

Regulation of a hormone by the level of certain substances

Regulation of a hormone by the nervous systemEndocrine glands whose secretions are partly regulated by the nervous system are:Adrenal medulla receives impulses from the efferent nerves of the nervous system and secretes adrenaline in responsePancreas after a meal, the pancreas receives efferent impulses from CNS to secrete insulin to reduce the blood glucose levelrevisionB

A

B

C

CCoordination involving both the nervous and endocrine systemFight or flight strategyA safety measure that prepares body to respond to dangerous/threatening stimuliInvolves a coordinated effort of both nervous system & endocrine system

22The nervous systemHypothalamus send impulses to adrenal cortex release adrenalineAdrenaline causes:More glycogen to be converted into glucose in the liverIncreased metabolic rateDeeper & rapid breathingFaster heartbeat and raised blood pressureBlood to be diverted from the surface areas of the body and the gut to the muscleEndocrine systemHypothalamus stimulates anterior pituitary gland adrenocorticotrophic hormone (ACTH) activate adrenal-corticol systemACTH moves through bloodstream to adrenal cortex activates corticoid hormones prepare body to deal with stress

Differences between the nervous and endocrine systemCharacteristicsNervous systemEndocrine syd stemType of messageNerve impulse-electrochemicalHormone-chemicalTransportVia nerve fibresVia the blood streamSpeed of transmissionRapidSlowAreas of responseLimited to places with nerve supplyAll over the body-one hormone may affect several target organs at the same timeNature of the responseCauses muscle to contract or glands to secreteCauses changes in the metabolic activityDuration of effectShort-lived and reversibleLong lastingHormonal imbalanceImbalance of growth hormoneDeficiency of growth hormone:In children : pituitary dwarfismAdults: diminished lean body mass, poor bone density

Imbalance of growth hormoneExcessive gigantism (children & adult)In adults: acromegaly (new bone tissue grow in the bodys extremities jaw protrudes, hands & feet greatly enlarged

Imbalance of ADHDeficiency causes diabetes insipidusCauses production of pale dilute urine dehydration & extreme thirstExcessive ADH:Causes kidney to absorb more water & less urineCerebral oedemaUse of hormone in medicineDiabetes mellitusType 1 diabetes : does not produce enough insulinType 2 diabetes: do not use insulin well enough to regulate sugar?

Why insulin cannot be taken as pill?