The Endocrine System. Exocrine vs Endocrine Classified by location of secretion Exocrine- through...
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Transcript of The Endocrine System. Exocrine vs Endocrine Classified by location of secretion Exocrine- through...
The Endocrine The Endocrine SystemSystem
Exocrine vs EndocrineExocrine vs Endocrine
Classified by location of secretionClassified by location of secretion
Exocrine- through tube or duct to a surfaceExocrine- through tube or duct to a surface
Endocrine- secrete into internal Endocrine- secrete into internal environmentenvironment
Endocrine GlandsEndocrine Glands
Can be cell, tissue, or organ (gland)Can be cell, tissue, or organ (gland)
Hormone- messenger secreted by glandHormone- messenger secreted by gland
Target cell- receives the messageTarget cell- receives the message– Receptor for hormoneReceptor for hormone– Hormone creates a responseHormone creates a response
Tropic hormones- hormone whose target Tropic hormones- hormone whose target cell is another endocrine glandcell is another endocrine gland
Other MessengersOther Messengers
““Local Hormones”- never reach Local Hormones”- never reach bloodstreambloodstream– Paracrine- affect neighboring cellsParacrine- affect neighboring cells– Autocrine- affect secreting cellAutocrine- affect secreting cell
Prostaglandins- lipids messenger usually Prostaglandins- lipids messenger usually affecting organ secreted inaffecting organ secreted in
Hormone ActionHormone Action
Steroid Hormone (derivative of Steroid Hormone (derivative of cholesterol)cholesterol)– Must be carried by plasma proteins through Must be carried by plasma proteins through
bloodstreambloodstream– Diffuse into any cellDiffuse into any cell– Binds to receptor in cell Binds to receptor in cell – Activates specific area of DNAActivates specific area of DNA– Protein synthesis is end resultProtein synthesis is end result– ExampleExample
Hormone Action (cont)Hormone Action (cont)
Nonsteriod hormone (amines, peptides, Nonsteriod hormone (amines, peptides, proteins)proteins)– Hormone (primary messenger) binds to Hormone (primary messenger) binds to
receptor on outside of cellreceptor on outside of cell– Binding causes activity center inside cell to Binding causes activity center inside cell to
activate a messenger (sometimes cAMP)activate a messenger (sometimes cAMP)– This second messenger cause the change in This second messenger cause the change in
the target cellthe target cell
Hormonal ControlHormonal Control
Stimulation of hormone releaseStimulation of hormone release– HypothalamusHypothalamus– Nervous systemNervous system– Changing internal environmentChanging internal environment
Inhibition of hormone releaseInhibition of hormone release– Negative feedback loopNegative feedback loop
HypothalamusHypothalamus
•Located deep inside the brain
•Releasing and inhibiting hormone secretion to anterior pituitary
•Direct innervation to posterior pituitary
Pituitary GlandPituitary Gland
•Located deep within the brain
•Divided into two sections
•Anterior Pituitary- glandular epithelium with many blood vessels
•Posterior Pituitary- nerve fibers and neuroglial cells
Tropic Hormones of the Anterior Tropic Hormones of the Anterior PituitaryPituitary
Thyroid-stimulating hormone (TSH)Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)Adrenocorticotropic hormone (ACTH)
GonadotropinsGonadotropins– Follicle-stimulating hormone (FSH)Follicle-stimulating hormone (FSH)– Lutenizing hormone (LH)Lutenizing hormone (LH)
Thyroid-stimulating hormone Thyroid-stimulating hormone (TSH)(TSH)
Stimulation: Thyrotropin-releasing Stimulation: Thyrotropin-releasing hormone (TRH) from hypothalamushormone (TRH) from hypothalamus
Inhibition: Circulating thyroid hormones Inhibition: Circulating thyroid hormones decrease TSH and TRH secretiondecrease TSH and TRH secretion
Target Cell: Thyroid Target Cell: Thyroid
Action: Increase thyroid secretions Action: Increase thyroid secretions
Adrenocorticotropic hormone Adrenocorticotropic hormone (ACTH)(ACTH)
Stimulation: Corticotropin-releasing Stimulation: Corticotropin-releasing hormone (CRH) from hypothalamushormone (CRH) from hypothalamus
Target Cell: Adrenal cortexTarget Cell: Adrenal cortex
Action: Increase adrenal cortex secretionsAction: Increase adrenal cortex secretions
Follicle-stimulating hormone Follicle-stimulating hormone (FSH)(FSH)
Stimulation: Gonadotropin-releasing Stimulation: Gonadotropin-releasing hormone from hypothalamushormone from hypothalamus
Target Cell: Gonads (testes in males and Target Cell: Gonads (testes in males and ovaries in females)ovaries in females)
Action:Action:– Female- maturation of egg; secretion of Female- maturation of egg; secretion of
estrogenestrogen– Male- development of spermMale- development of sperm
Lutenizing hormone (LH)Lutenizing hormone (LH)
Also called Interstitial cell stimulating hormone Also called Interstitial cell stimulating hormone (ICSH)(ICSH)Stimulation: Gonadotropin-releasing hormone Stimulation: Gonadotropin-releasing hormone from hypothalamusfrom hypothalamusTarget Cell: Gonads (testes in males and Target Cell: Gonads (testes in males and ovaries in females)ovaries in females)Action:Action:– Female- release of mature egg from ovary (ovulation)Female- release of mature egg from ovary (ovulation)– Male- development of interstitial cell; secretion of Male- development of interstitial cell; secretion of
male sex hormonesmale sex hormones
Other hormone of the Anterior Other hormone of the Anterior PituitaryPituitary
Growth Hormone (GH)Growth Hormone (GH)– Stimulation: GH-releasing hormone from Stimulation: GH-releasing hormone from
hypothalamushypothalamus– Inhibition: GH release-inhibiting hormoneInhibition: GH release-inhibiting hormone– Target Cell: Somatic cells Target Cell: Somatic cells – Action: enhances movement of amino acids Action: enhances movement of amino acids
across cell membrane; speeds up rate of across cell membrane; speeds up rate of carbohydrate utilizationcarbohydrate utilization
Other hormone of the Anterior Other hormone of the Anterior Pituitary (cont)Pituitary (cont)
Prolactin (PRL)Prolactin (PRL)– Stimulates breast development necessary for Stimulates breast development necessary for
lactationlactation– Stimulates breast to secrete milk after birthStimulates breast to secrete milk after birth
Posterior PituitaryPosterior Pituitary
Antidiuretic hormone (ADH)Antidiuretic hormone (ADH)– Stimulation: Nerve Impulse from hypothalamus when Stimulation: Nerve Impulse from hypothalamus when
osmoreceptors sense dehydrationosmoreceptors sense dehydration– Target Cell: kidneys Target Cell: kidneys – Action: kidneys produce less urine to conserve waterAction: kidneys produce less urine to conserve water
Oxytocin (OT)Oxytocin (OT)– Stimulates contraction of the pregnant uterusStimulates contraction of the pregnant uterus– Stimulates “let-down” of milkStimulates “let-down” of milk
ThyroidThyroid
•Location: attached to front of trachea
•Contains follicles
•Follicles have hollow center cavity filled with colloid
Thyroid (cont)Thyroid (cont)
Follicular cells secrete two hormonesFollicular cells secrete two hormones– Thyroxine (tetraiodothyronine)- TThyroxine (tetraiodothyronine)- T44
– Triiodothyronine- TTriiodothyronine- T3 3 (much more potent)(much more potent)– Increases metabolism of carbohydrates, Increases metabolism of carbohydrates,
lipids, and proteinslipids, and proteins
Extrafollicular cells secrete calcitoninExtrafollicular cells secrete calcitonin– Lowers blood calcium level by inhibiting Lowers blood calcium level by inhibiting
osteoclasts and making kidney secrete more osteoclasts and making kidney secrete more calcium in urinecalcium in urine
Parathyroid glandsParathyroid glands
Located on the thyroid in four patches of Located on the thyroid in four patches of highly dense secretory cellshighly dense secretory cells
Secrete Parathyroid hormone (PTH)Secrete Parathyroid hormone (PTH)– Raises blood calcium levelsRaises blood calcium levels– Inhibits osteoblasts, stimulates osteoclasts, Inhibits osteoblasts, stimulates osteoclasts,
makes kidneys conserve calcium, increase makes kidneys conserve calcium, increase absorption of calcium in intestineabsorption of calcium in intestine
Adrenal glandsAdrenal glands
Adrenal CortexAdrenal Cortex
Three layers: outer, middle, and innerThree layers: outer, middle, and inner
Closely packed masses of epithelial tissueClosely packed masses of epithelial tissue
Outer Layer of CortexOuter Layer of Cortex
Outer (glomerulosa)Outer (glomerulosa)– Mineralocorticoid (MC)- regulate mineral Mineralocorticoid (MC)- regulate mineral
electrolyteselectrolytesAldosteroneAldosterone
– Stimulated by decrease in blood levels of sodium, Stimulated by decrease in blood levels of sodium, increase in potassium in blood levels, or decrease in increase in potassium in blood levels, or decrease in blood pressureblood pressure
– Cause kidneys to retain sodium and secrete potassium Cause kidneys to retain sodium and secrete potassium into urineinto urine
– Indirectly water will be retained as wellIndirectly water will be retained as well
Adrenal Cortex (cont)Adrenal Cortex (cont)
Middle (fasciculata)Middle (fasciculata)– Glucocorticoids- affects glucose metabolismGlucocorticoids- affects glucose metabolism
Cortisol or hydrocortisoneCortisol or hydrocortisone– Increase gluconeogenisisIncrease gluconeogenisis– Inhibition of protein synthesisInhibition of protein synthesis– Promotion of fatty acid release from adipose tissuePromotion of fatty acid release from adipose tissue– Produce state of stressProduce state of stress
Adrenal Cortex (cont)Adrenal Cortex (cont)
Inner (reticularis)Inner (reticularis)– Sex hormones Sex hormones
Produces androgen hormonesProduces androgen hormones
Can be used to synthesize female sex hormones Can be used to synthesize female sex hormones like estrogenslike estrogens
Adrenal MedullaAdrenal Medulla
Composed of modified neuronsComposed of modified neuronsSecrete epinephrine (adrenaline) and Secrete epinephrine (adrenaline) and norepinephrine (noradrenaline)norepinephrine (noradrenaline)
““Fight or Flight” responseFight or Flight” response
Directly innervated by sympathetic Directly innervated by sympathetic nervous systemnervous system
Pancreatic Islets (Islets of Pancreatic Islets (Islets of Langerhans)Langerhans)
Alpha cellsAlpha cells– GlucagonGlucagon
Accelerates process of gylcogenolysisAccelerates process of gylcogenolysis
Beta cellsBeta cells– InsulinInsulin
Increeases movement of glucose inside of cells for Increeases movement of glucose inside of cells for metabolismmetabolism
Stimulates liver to produce glycogenStimulates liver to produce glycogen
ThymusThymus
•Located in mediastinum cavity
•Hormones called thymosins
•Important function in development of immune system
Pineal glandPineal gland
Releases melatoninReleases melatonin
– Regulates body clock and sleep cycleRegulates body clock and sleep cycle
Female Sex GlandsFemale Sex Glands
OvariesOvaries
Ovarian Ovarian follicles follicles
Corpus Corpus luteumluteum
Male sex glandsMale sex glands
TestesTestes
– Interstitial cells produce testosteroneInterstitial cells produce testosterone
– Testosterone stimulates sperm productionTestosterone stimulates sperm production
PlacentaPlacenta
•Chorionic gonadotropins
•Pregnancy tests test for this hormone
•Prevents dissolution of corpus luteum
Other hormonesOther hormones
Wall of Atria in HeartWall of Atria in Heart– Atrial Natriuretic hormone- regulates fluid and Atrial Natriuretic hormone- regulates fluid and
electrolyte balance by increasing removal of electrolyte balance by increasing removal of sodium and watersodium and water
Various Digestive GlandsVarious Digestive Glands
KidneysKidneys– Erythropoietin- red blood cell growth hormoneErythropoietin- red blood cell growth hormone