ENDOCRINE ENDOCRINE SYSTEMSYSTEM

Charles C. Cook, MDCharles C. Cook, MD

Endocrine system is complex and Endocrine system is complex and illness associated with it are illness associated with it are sometimes very difficult to sometimes very difficult to diagnose.diagnose.

ENDOCRINE SYSTEM ENDOCRINE SYSTEM

Regulating the Regulating the functions of the Human functions of the Human

BodyBodyNervous System: Nervous System:

Biological communication systemBiological communication system

Endocrine System:Endocrine System:

Uses biochemicals called Uses biochemicals called hormoneshormones that travel in body that travel in body fluids and act as fluids and act as chemical chemical messengersmessengers to their target cells to their target cells

Endocrine SystemEndocrine System

A system of glands that A system of glands that function in the function in the

coordination of body coordination of body activities through activities through

chemical messengerschemical messengers

Endocrine Endocrine GlandsGlands

Have Have no ductsno ductsSecrete hormones Secrete hormones

–into into extracellular extracellular fluidsfluids

–diffuse into the diffuse into the bloodstreambloodstream

Endocrine Endocrine GlandsGlands

Pituitary glandPituitary glandThyroid glandThyroid glandParathyroid glandsParathyroid glandsAdrenal glandsAdrenal glandsPancreasPancreas

Exocrine GlandsExocrine Glands Secrete products through Secrete products through ductsducts

that lead to the lumen of an that lead to the lumen of an organ, body surface or body organ, body surface or body cavitycavity

Example:Example: – Sweat glandsSweat glands– Salivary glands Salivary glands – Liver and Gall bladderLiver and Gall bladder

HormonesHormonesandand

Negative Negative FeedbackFeedback

HormonesHormones Chemical messengerChemical messenger

–Endocrine glandEndocrine gland–Blood or body fluidsBlood or body fluids

Target: Target: specific site on a cell, specific site on a cell, tissue, organ or organ system tissue, organ or organ system with hormone bindswith hormone binds

Hypersecretion: Hypersecretion: greater than greater than normalnormal

Hyposecretion: Hyposecretion: less than normalless than normal

HormonesHormonesChemical released from an Chemical released from an

endocrine gland thatendocrine gland thatAffects function of a Affects function of a target celltarget cellDiffuses into the bloodDiffuses into the bloodCarried through the bodyCarried through the bodyAct on cells that have specific Act on cells that have specific

receptor receptor (hormone can attach)(hormone can attach)

Negative Negative FeedbackFeedback

Secretion of most hormones Secretion of most hormones by endocrine glandby endocrine gland

Mechanism forMechanism for–Maintaining stable Maintaining stable amount of hormone in amount of hormone in the blood streamthe blood stream

Negative Negative FeedbackFeedback

ExampleExampleThyroid hormone falls below Thyroid hormone falls below

normalnormal–Hypothalamus detects Hypothalamus detects the decreasethe decrease

Hypothalamus signal Hypothalamus signal –Anterior pituitary gland Anterior pituitary gland to secrete TSHto secrete TSH

TSHTSH cause the cause the thyroid thyroid to make to make & secrete more & secrete more TH (Thyroxine)TH (Thyroxine)

Level of Level of THTH in the blood returns in the blood returns to to normalnormal

HigherHigher concentration of concentration of THTH shuts off the signal both shuts off the signal both hypothalamus & pituitary gland hypothalamus & pituitary gland that led tothat led to

Increase Increase in secretion of in secretion of THTH

Functions of the Functions of the Endocrine SystemEndocrine System

Help to control internal environmentHelp to control internal environment Respond to marked changesRespond to marked changes Helps with growth and developmentHelps with growth and development Helps with reproduction processHelps with reproduction process Regulate metabolismRegulate metabolism

–Maintain homeostatasisMaintain homeostatasis–F/E and Acid Base BalanceF/E and Acid Base Balance

The The Major Major

Endocrine Endocrine OrgansOrgans

Major Endocrine Major Endocrine OrgansOrgans

HypothalamusHypothalamus Pituitary GlandsPituitary Glands

– Anterior lobeAnterior lobe– Posterior lobePosterior lobe

Thyroid GlandsThyroid Glands Parathyroid GlandsParathyroid Glands

Adrenal GlandsAdrenal Glands– Adrenal Adrenal cortexcortex

– Adrenal Adrenal medullamedulla

PancreasPancreas

HypothalamusHypothalamusMiddle of the brain near floor of Middle of the brain near floor of

the cranial cavitythe cranial cavityConnection between Connection between nervous nervous

and and endocrine systemendocrine systemSensory information & signals Sensory information & signals

to pituitary glands to pituitary glands to secrete to secrete or not secrete hormonesor not secrete hormones

Pituitary GlandsPituitary GlandsThe Master GlandThe Master GlandBase of the brain Base of the brain (1cm in dia)(1cm in dia) In the In the sella turcisasella turcisaBony pocket of the cranial Bony pocket of the cranial

cavitycavityHas an Has an Anterior and Posterior Anterior and Posterior LobeLobe

75% Total Wt.

Anterior Pituitary GlandAnterior Pituitary GlandReleases 7 major Releases 7 major

hormoneshormones Growth Hormone Growth Hormone (GH)(GH) Prolactin Prolactin (PRL)(PRL) Thyroid Stimulating Hormone Thyroid Stimulating Hormone (TSH)(TSH) Melanocyte Stimulating HormoneMelanocyte Stimulating Hormone

(MSH)(MSH) Adrenocorticotrophic Hormone Adrenocorticotrophic Hormone (ACTH)(ACTH) Follicle Stimulating Hormone Follicle Stimulating Hormone (FSH)(FSH) Lutenizing Hormone Lutenizing Hormone (LH)(LH)

Anterior Pituitary Anterior Pituitary HormonesHormones

GH-GH- mainly promotes the mainly promotes the lengthwise growthlengthwise growth of long of long bones bones (Somatotropic)(Somatotropic)

Prolactin- Prolactin- stmulates breast stmulates breast development and lactation after development and lactation after childbirthchildbirth

TSH-TSH- stimulating the thyroid stimulating the thyroid glandgland (Thyroxine & (Thyroxine & Triiodothyronine) Triiodothyronine)

Anterior Pituitary Anterior Pituitary HormonesHormones

ACTH-ACTH- stimulates the adrenal stimulates the adrenal cortex to secrete cortex to secrete cortisolcortisol

LH-LH- regulates the functions of regulates the functions of estrogen, progesterone estrogen, progesterone andand testosterone testosterone productionproduction

FSH-FSH- regulates the functions of regulates the functions of the the spermsperm and and eggegg production production

Posterior Pituitary Posterior Pituitary GlandGland

Nerve fiber (impulses)Nerve fiber (impulses)Releases two hormonesReleases two hormones

–Antidiuretic hormone Antidiuretic hormone (ADH)(ADH)

–Oxytocin (OT)Oxytocin (OT)

Thyroid-Stimulating Thyroid-Stimulating HormoneHormone

a.k.a. a.k.a. TSHTSHFunctionFunction

–Stimulates the thyroid Stimulates the thyroid gland to secrete more of gland to secrete more of the thyroid hormone the thyroid hormone (Thyroxine)(Thyroxine)

Adrenocorticotropic Adrenocorticotropic HormoneHormone

a.k.a a.k.a ACTHACTHStimulate the Stimulate the adrenal adrenal cortexcortex to manufacture & to manufacture & secrete its hormonessecrete its hormones

Mostly cortisolMostly cortisol–but also other hormonesbut also other hormones

RegulatesRegulatesCortisol levels in the blood Cortisol levels in the blood are are Lower than normalLower than normal

Hypothalamus Hypothalamus stimulatesstimulates the anterior pituitary gland the anterior pituitary gland to to secrete ACTHsecrete ACTH

Cortisol levels in the blood is Cortisol levels in the blood is Normal or higher than normalNormal or higher than normal

Cortisol Cortisol inhibitsinhibits the the hypothalamus from stimulating hypothalamus from stimulating the the secretion of ACTHsecretion of ACTH

InhibitsInhibits the anterior pituitary the anterior pituitary from secreting ACTH from secreting ACTH (-) feedback(-) feedback

RegulatesRegulates

The The Thyroid Thyroid GlandGland

Thyroid GlandThyroid GlandLocation in the front of the Location in the front of the

neck around the neck around the –LarynxLarynx–TracheaTrachea

Main hormone of the thyroid Main hormone of the thyroid gland is gland is –Thyroxine and CalcitoninThyroxine and Calcitonin

ThyroxineThyroxineRegulates the Regulates the metabolic ratemetabolic rate of of

the whole bodythe whole bodyLevels of thyroxineLevels of thyroxine

–Increased: Increased: speed upspeed up metabolic metabolic raterate

–Decreased: Decreased: slowsslows metabolic rate metabolic rate

Thyroid DisordersThyroid Disorders

GoiterGoiterHyperthyroidismHyperthyroidism

–ExcessiveExcessive secretion secretionHypothyroidismHypothyroidism

–InadequateInadequate secretion secretion

GoiterGoiter

Enlarged thyroid glandEnlarged thyroid gland–tells you something tells you something is wrongs is wrongs

–Doesn’t tell you Doesn’t tell you what is wrongwhat is wrong

HyperthyroidismHyperthyroidismExcessiveExcessive secretion of secretion of thyroxinethyroxine

All sign & symptoms are rated All sign & symptoms are rated to to increase in metabolic rateincrease in metabolic rate-increase heart-increase heart-increase body temp-increase body temp-fatigue-fatigue-weight loss-weight loss

Hyperthyroidism

Produces-elevated metabolic rate-restlessness-overeating-eyes protrude-thyroid glands enlarged (goiter)

HypothyroidismHypothyroidismInadequateInadequate secretion of secretion of ThyroxineThyroxine

All signs & symptoms are All signs & symptoms are related to a related to a decreasedecrease in the in the metabolic ratemetabolic rate–decreasedecrease heart & heart & respiratory raterespiratory rate

–constipation & weigh constipation & weigh gaingain

– decreasedecrease body body temperaturetemperatureintolerance of coldintolerance of cold

HypothyroidismHypothyroidism

CretinismSymptoms-stunted growth-abnormal development-low body temp-sluggishness

Hypothyroidism

Parathyroid GlandsParathyroid GlandsLocated Located posterior surfaceposterior surface of the of the thyroid glandthyroid gland

There’s There’s 4 structure4 structure–2 superior glands2 superior glands–2 inferior glands2 inferior glands

Parathyroid Parathyroid hormonehormone

RegulateRegulate calcium level calcium level in the in the bloodblood

When When PTHPTH secreted secreted–IncreaseIncrease blood calcium levels blood calcium levels–DecreaseDecrease blood phosphate levels blood phosphate levels

Affects the bones, kidneys, and Affects the bones, kidneys, and intestineintestine

The The Adrenal Adrenal

GlandGland

Adrenal GlandsAdrenal Glands

Located atop of each kidneyLocated atop of each kidneyAdrenal medullaAdrenal medulla- is the - is the center center (core)(core) layer portion layer portion

Adrenal cortexAdrenal cortex- is the - is the outer layer portionouter layer portion

Adrenal CortexAdrenal Cortex Three layers that synthesize Three layers that synthesize

corticoidscorticoids Outer (core) layerOuter (core) layer ThreeThree adrenal hormones adrenal hormones

–AldosteroneAldosterone–GlucocorticoidsGlucocorticoids–Adrenal AndrogensAdrenal Androgens

AldosteroneAldosteroneRegulates Regulates mineral mineral electrolyteselectrolytes

Kidneys to conserve Kidneys to conserve sodium sodium & & waterwater excrete excrete potassiumpotassium

If blood pressure falls- If blood pressure falls- kidney kidney indirectly stimulate indirectly stimulate aldosterone secretionaldosterone secretion

GlucocorticoidsGlucocorticoidsPlays a role in maintenance of Plays a role in maintenance of

blood pressureblood pressure Influences Influences Glucose Glucose MetabolismMetabolism

Adrenal AndrogensAdrenal Androgens–Minimal levels of Minimal levels of testosterone are producedtestosterone are produced

Adrenal MedullaAdrenal MedullaSecretes 2 hormonesSecretes 2 hormones

--epinephrineepinephrine

--norepinephrinenorepinephrine80% is epinephrine80% is epinephrine

Prepares the body for Prepares the body for –Action Action –StressStress

Sympathetic Nerve SystemSympathetic Nerve System --flight or fightflight or fight --Adrenaline rushAdrenaline rush

Resulting In:Resulting In:–increase increase

heart rateheart rateblood pressureblood pressurerespirationrespirationblood sugar levelblood sugar level

–decreased decreased digestive ratedigestive rate

The The PancreasPancreas

PancreasPancreasLocation- behind the stomachLocation- behind the stomachExocrineExocrine-- secretes secretes digestive juice (pancreatic digestive juice (pancreatic duct)duct) into small intestine into small intestine

EndocrineEndocrine- Islets of - Islets of LangerhansLangerhans

HormonesHormonesInsulin:Insulin: Promotes the Promotes the transport of glucose from transport of glucose from the blood into the cellsthe blood into the cells

Glucagon:Glucagon: Stimulates Stimulates the release of the stored the release of the stored glucose from the liver glucose from the liver intointo the blood the blood

Diabetes MellitusDiabetes Mellitus

Metabolic disorder;Metabolic disorder; blood blood glucose levels are glucose levels are –CHRONICALLY HIGHCHRONICALLY HIGH

Type I-Type I- can not produce can not produce enough insulinenough insulin

Type II-Type II- insulin resistance insulin resistance

Signs and Signs and SymptomsSymptoms

The The four (P’s)four (P’s)(Polyuria)(Polyuria) Frequent urination Frequent urination(Polydipsa) (Polydipsa) Chronic thirstChronic thirst(Polyphagia)(Polyphagia) Chronic hunger Chronic hunger(Poor wt maintenance) (Poor wt maintenance) Weight problemsWeight problems

Type IType I–destruction of the destruction of the beta beta cellscells

Type IIType II–decrease or no response decrease or no response on the on the target cellstarget cells (mostly (mostly liver, skeletal, muscle, and liver, skeletal, muscle, and adipose tissue)adipose tissue)

–is almost is almost always obesealways obese

Gonads/Sex GlandsGonads/Sex Glands Ovaries and TestesOvaries and Testes

– Male and female gamete producing Male and female gamete producing glandsglands

TestesTestes– Located scrotal sacLocated scrotal sac– Produce TestosteroneProduce Testosterone

OvariesOvaries– Located in pelvic regionLocated in pelvic region– Produces estrogen and Produces estrogen and progesteroneprogesterone

Thymus GlandThymus Gland

Cortex and Medulla regionCortex and Medulla region–Largely composed of Largely composed of lymphocyteslymphocytes

Hormone produced ThymosinHormone produced Thymosin–Activate immune systemActivate immune system–Production of certain Production of certain lymphocyteslymphocytes–Important role in immunityImportant role in immunity

Endocrine GlandsEndocrine Glands Digestive glandsDigestive glands

– Stomach and small intestineStomach and small intestine ErythropoietinErythropoietin

– Secreted by the kidneysSecreted by the kidneys Atria Natriuretic Factor (ANF)Atria Natriuretic Factor (ANF)

– Secreted by the cell in the Secreted by the cell in the walls of the atriawalls of the atria

– ANF is an antagonistANF is an antagonist– Decreases blood volumeDecreases blood volume

That’s That’s It!!!!!!It!!!!!!