Endocrine SystemEndocrine SystemTypes of hormones and homeostasisTypes of hormones and homeostasisNegative feedbackNegative feedbackEndocrine glands overviewEndocrine glands overviewThe pituitaryThe pituitaryPosterior pituitaryPosterior pituitaryAnterior pituitaryAnterior pituitaryThyroxin - metabolismThyroxin - metabolismPTH and Calcitonin - blood calciumPTH and Calcitonin - blood calciumInsulin / glucagon – blood sugarInsulin / glucagon – blood sugarAdrenal GlandsAdrenal GlandsOther glandsOther glands

Recap: HomeostasisRecap: Homeostasis• Homeostasis Homeostasis – is a state of – is a state of

equilibrium where an organism’s equilibrium where an organism’s internal environment remains internal environment remains relatively constant, despite ongoing relatively constant, despite ongoing environmental changes.environmental changes.

Recap: Negative FeedbackRecap: Negative Feedback• prevents chemical prevents chemical

imbalances in the imbalances in the body. body.

• Once the body has Once the body has responded to a responded to a change in the change in the environment, the environment, the effect is detected, effect is detected, receptors are receptors are activated, and further activated, and further response is inhibitedresponse is inhibited..

Examples of Negative Examples of Negative FeedbackFeedback

Two Categories of GlandsTwo Categories of Glands

1.1. Exocrine GlandsExocrine Glands –products do not –products do not enter the bloodstream, but are enter the bloodstream, but are released by ducts or tubes into a released by ducts or tubes into a body cavity, or out of the body. body cavity, or out of the body.

Ex) sweat glands, and salivary Ex) sweat glands, and salivary glands.glands.

2.2. Endocrine GlandsEndocrine Glands –release –release hormones into the blood streamhormones into the blood stream

Hormones in the BodyHormones in the Body

HypothalamusHypothalamus

• Produces Produces Anti-Diuretic Hormone and Oxytocin-stored in the posterior pituitary

gland

• Produces releasing and inhibiting factors to control the pituitary gland

Pituitary HormonesPituitary Hormones• Pituitary GlandPituitary Gland

– the master glandthe master gland

Posterior PituitaryPosterior Pituitary – –stores and releases ADH and oxytocin

Anti-Diuretic Hormone (ADH)Anti-Diuretic Hormone (ADH) – – increases water re-absorption by the increases water re-absorption by the kidneys when the blood becomes too kidneys when the blood becomes too concentrated with solutesconcentrated with solutes

– Diabetes insipidusDiabetes insipidus – excessive – excessive urination, dehydration and thirst urination, dehydration and thirst resulting from a lack of ADH, resulting from a lack of ADH, usually caused by a tumorusually caused by a tumor

Ex)Ex) Oxytocin – Oxytocin – stimulates uterine stimulates uterine contractions contractions during childbirth, during childbirth, and triggers and triggers initial milk initial milk productionproduction– PitocinPitocin – is a – is a

synthetic form synthetic form of oxytocin that of oxytocin that is often given to is often given to induce labour.induce labour.

Anterior PituitaryAnterior Pituitary – – producesproduces hormones which are controlled hormones which are controlled by releasing factor secreted by by releasing factor secreted by the hypothalamus.the hypothalamus.

Ex)Ex) Thyroid Stimulating Thyroid Stimulating Hormone (TSH)Hormone (TSH) – stimulates – stimulates the thyroid gland to release the thyroid gland to release thyroxin (controls metabolism) thyroxin (controls metabolism) and calcitonin (controls blood and calcitonin (controls blood calcium)calcium)

Ex)Ex) Adrenocorticotropic Adrenocorticotropic Hormone (ACTH)Hormone (ACTH) – stimulates – stimulates the adrenal cortex to release the adrenal cortex to release aldosterone and cortisol which aldosterone and cortisol which regulate the release of fatty regulate the release of fatty acids in the blood and regulate acids in the blood and regulate fat metabolismfat metabolism

Ex)Ex) Prolactin Hormone (PRL) Prolactin Hormone (PRL) – – stimulates milk production in the stimulates milk production in the mammary glands after birth, mammary glands after birth, suckling or other stimulation suckling or other stimulation may result in the “let down” may result in the “let down” reflexreflex

Ex)Ex) Follicle Stimulating Hormone Follicle Stimulating Hormone (FSH)(FSH) – stimulates the production of – stimulates the production of gametes (sperm and egg) in the male gametes (sperm and egg) in the male and female reproductive systemsand female reproductive systems

Ex)Ex) Luteinizing Hormone (LH) Luteinizing Hormone (LH) – – stimulates the production of stimulates the production of hormones (estrogen, progesterone hormones (estrogen, progesterone and testosterone) in the male and and testosterone) in the male and female reproductive systemsfemale reproductive systems

Ex)Ex) human Growth Hormone human Growth Hormone (hGH) –(hGH) – regulates the growth regulates the growth of bones and tissues during of bones and tissues during childhood by assisting amino childhood by assisting amino acids across cell membranes for acids across cell membranes for protein synthesis.protein synthesis.

• GigantismGigantism – – overproduction overproduction of growth of growth hormone during hormone during the growth years, the growth years, results in very results in very large individuals large individuals (7-9 ft)(7-9 ft)

• often have often have diabetes and diabetes and other medical other medical issues.issues.

• AcromegalyAcromegaly – overproduction of growth – overproduction of growth hormone during the adult years, results in hormone during the adult years, results in excessive growth of the cartilage of the excessive growth of the cartilage of the nose, hands, feet, jaw, tongue and internal nose, hands, feet, jaw, tongue and internal organsorgans..

The World’s tallest woman.The World’s tallest woman.Defen is 34 years old and Defen is 34 years old and

7ft 8" tall. 7ft 8" tall.

• DwarfismDwarfism – – underproduction of underproduction of growth hormone growth hormone during the growth during the growth years and years and adolescence, adolescence, results in results in individuals of short individuals of short stature with stature with proportionate or proportionate or disproportionate disproportionate size.size.

• Extra: Extra: Melanocyte Stimulating Melanocyte Stimulating Hormone (MSH)Hormone (MSH) – affects skin – affects skin pigmentationpigmentation

Thyroid GlandThyroid Gland The thyroid gland is responsible The thyroid gland is responsible

for the secretion of two for the secretion of two hormones:hormones:

1.1. ThyroxinThyroxin – increases the rate of – increases the rate of cellular respiration by cellular respiration by increasing oxygen uptake in increasing oxygen uptake in cellscells

-Regulates metabolism-Regulates metabolism

2.2. CalcitoninCalcitonin – decreases the – decreases the concentration concentration of blood calcium of blood calcium

-Decreases the rate that calcium -Decreases the rate that calcium leaves the bones, reduces leaves the bones, reduces intestinal uptake of calcium, and intestinal uptake of calcium, and reduces reabsoprtion of calcium reduces reabsoprtion of calcium by the kidneys. (Works in by the kidneys. (Works in opposition to parathyroid opposition to parathyroid hormone)hormone)

Thyroid DisordersThyroid Disorders

• HyperthyroidismHyperthyroidism – excessive – excessive production of thyroxin results in production of thyroxin results in nervousness, weight loss, sweating, nervousness, weight loss, sweating, tachycardia, hyperactivitytachycardia, hyperactivity

• HypothyroidismHypothyroidism – underproduction of – underproduction of thyroxin results in sluggishness, thyroxin results in sluggishness, depression, weight gain, tiredness, goiterdepression, weight gain, tiredness, goiter

– Goiter may also be caused by a lack of Goiter may also be caused by a lack of iodine in the diet.iodine in the diet.

• CretinismCretinism – hypothyroidism in a – hypothyroidism in a developing infant results in developing infant results in permanent and severe retardation permanent and severe retardation and stunted growthand stunted growth

Thyroid SurgeryThyroid Surgery

Parathyroid GlandParathyroid Gland • a set of four pea-sized glands a set of four pea-sized glands

embedded in the posterior portion of embedded in the posterior portion of the thyroid. the thyroid.

• Parathyroid Hormone (PTH)Parathyroid Hormone (PTH) – – increases blood calcium increases blood calcium – increases removal of calcium ions increases removal of calcium ions

from bones and increases re-from bones and increases re-absorption of calcium ions from the absorption of calcium ions from the kidneys.kidneys.

• TetanyTetany – – underproduction of the underproduction of the parathyroid (low blood calcium) parathyroid (low blood calcium) resulting in muscle spasms, resulting in muscle spasms, convulsions and nervous twitchesconvulsions and nervous twitches

• OsteoporosisOsteoporosis – demineralization – demineralization of the bones due to overproduction of the bones due to overproduction of the parathyroid, or lack of of the parathyroid, or lack of calciumcalcium– very common after menopause due to very common after menopause due to

lowered estrogen levels (estrogen lowered estrogen levels (estrogen counters the effect of PTH)counters the effect of PTH)

The PancreasThe Pancreas

• Islets of LangerhansIslets of Langerhans – are glandular clusters of cells – are glandular clusters of cells in the pancreas that produce insulin and glucagonin the pancreas that produce insulin and glucagon

Alpha cellsAlpha cells – produce glucagon, – produce glucagon, which stimulates the conversion of which stimulates the conversion of glycogen to glucose by the liver glycogen to glucose by the liver raising blood glucoseraising blood glucose

Beta cellsBeta cells – produce insulin, which – produce insulin, which stimulates the uptake of glucose stimulates the uptake of glucose by the body’s cells, lowering blood by the body’s cells, lowering blood glucoseglucose

Regulation of Blood SugarRegulation of Blood Sugar

Blood Sugar DisordersBlood Sugar Disorders

• Diabetes MellitisDiabetes Mellitis –sugar –sugar diabetes ordiabetes or hyperglycemiahyperglycemia– blood sugar is very high (while blood sugar is very high (while

cellular glucose is too low) cellular glucose is too low) – increased urination, fruity odour increased urination, fruity odour

on the breath, weight loss, fatigue, on the breath, weight loss, fatigue, blindnessblindness

– Type I /Juvenile OnsetType I /Juvenile Onset – the – the inability to produce insulin, inability to produce insulin, degeneration of beta cellsdegeneration of beta cells

– Type II / Adult OnsetType II / Adult Onset – – decreased insulin production decreased insulin production or ineffective use of insulin or ineffective use of insulin (may be related to insulinase)(may be related to insulinase)

• Diabetic Coma Diabetic Coma – slow onset, lack of – slow onset, lack of insulin that result in the brain being insulin that result in the brain being deprived of glucose, and eventually deprived of glucose, and eventually shutting down (insulin is required)shutting down (insulin is required)

• Insulin Shock Insulin Shock – sudden excess – sudden excess amount of insulin causing dizziness, amount of insulin causing dizziness, sweating, hunger, confusion, normal sweating, hunger, confusion, normal urine output (sugar is required)urine output (sugar is required)

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Adrenal GlandsAdrenal Glands • located just above the kidneyslocated just above the kidneys• composed of outer cortex and an inner composed of outer cortex and an inner

medulla which produce different hormonesmedulla which produce different hormones..

Adrenal MedullaAdrenal Medulla

Adrenaline/EpinephrineAdrenaline/Epinephrine – released to – released to elicit the fight or flight response during elicit the fight or flight response during short term stress, causes:short term stress, causes:

• increased blood glucoseincreased blood glucose• increased heart rateincreased heart rate• increased metabolismincreased metabolism• increased blood flow to the skeletal increased blood flow to the skeletal

musclesmuscles• decreased rate of digestiondecreased rate of digestion• relaxes smooth muscles in the walls of relaxes smooth muscles in the walls of

the bronchiolesthe bronchioles

Adrenal CortexAdrenal Cortex --stimulated by Adrenocorticotropic stimulated by Adrenocorticotropic

HormoneHormone

Produces three classes of hormones:Produces three classes of hormones:

1.1. Sex hormonesSex hormones – small amounts of – small amounts of both male and female sex both male and female sex hormones are released by the hormones are released by the adrenal cortex. Over-activity adrenal cortex. Over-activity causes masculinization of females causes masculinization of females and feminization of males.and feminization of males.

2.2. Cortisol Cortisol – is a glucocorticoid( steroid – is a glucocorticoid( steroid that binds with that binds with glucocorticoid receptors)glucocorticoid receptors)

-long term stress-long term stress

--breaks down muscle proteins to produce breaks down muscle proteins to produce amino acids which are converted into amino acids which are converted into glucose in response to stressglucose in response to stress

- stimulates the metabolism of fatty stimulates the metabolism of fatty acids raising the blood glucose. acids raising the blood glucose.

- counter the inflammatory responsecounter the inflammatory response..

• Aldosterone Aldosterone – is a – is a mineralocorticoid (steroid that mineralocorticoid (steroid that binds to binds to mineralocorticoid receptor). mineralocorticoid receptor). – regulates Na+/K+ levels and regulates Na+/K+ levels and

maintains blood pressure. maintains blood pressure. – promotes absorption of Na+ ions by promotes absorption of Na+ ions by

the kidney, drawing in water and the kidney, drawing in water and thus increasing blood pressure.thus increasing blood pressure.

Adrenal DisordersAdrenal Disorders• Cushing’s Cushing’s

SyndromeSyndrome – over – over activity of the activity of the adrenal cortex adrenal cortex resulting in resulting in edema, moonlike edema, moonlike face, face, masculinization of masculinization of females, and high females, and high blood sugarblood sugar..

• Addison’s DiseaseAddison’s Disease – under- – under-activity of the adrenal cortex activity of the adrenal cortex resulting in low blood pressure, resulting in low blood pressure, acidosis, fainting, increased risk acidosis, fainting, increased risk of infection and bronzing of the of infection and bronzing of the skin.skin.

Extra: Other HormonesExtra: Other Hormones

• Thymus – Thymus – secrete thymosin that secrete thymosin that stimulates maturation and stimulates maturation and differentiation of the T-cells in the differentiation of the T-cells in the immune system (most active in children immune system (most active in children with developing immune systems)with developing immune systems)

• MelatoninMelatonin – secreted by the pineal – secreted by the pineal gland, regulates circadian rhythms gland, regulates circadian rhythms such as sleep/wake cycles, such as sleep/wake cycles, migration, mating and sexual migration, mating and sexual development.development.

• ProstaglandinsProstaglandins – made by tissue not glandsmade by tissue not glands– Not delivered in bloodNot delivered in blood– Act on the cells that make them or Act on the cells that make them or

nearby tissuenearby tissue

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• Pheromones Pheromones – are messengers that – are messengers that act between individuals of a species, act between individuals of a species, secreted to attract a mate, mark secreted to attract a mate, mark territory, provide warning of danger.territory, provide warning of danger.