The Endocrine System

The The Endocrine Endocrine

SystemSystem

Major Endocrine

Organs

pineal glandhypothalamuspituitary gland

thyroid glandparathyroid glands

thymus gland

adrenal glands

pancreas

ovaries

testes

pineal glandhypothalamus

pituitary gland

Endocrine Organs of the Brain

Endocrine Organs of the Brain

• Secreted directly in CSF to blood

• High levels at night make us sleepy; low level during day

• Pineal gland is stimulated by darkness and inhibited by light

• Function in regulating circadian rhythms (sleep, body temp, appetite) biological clock

Pineal GlandPineal GlandProduces melatonin (synthesized from seratonin, a derivative of tryptophan)

The Pituitary GlandThe Pituitary Gland

Posterior Pituitary

Hormones of the Posterior

Pituitary

Antidiuretic Hormone (ADH)

Oxytocin

(+ feedback)loop

oxytocin

Anterior PituitaryAnterior Pituitary

Hormones of the Anterior Pituitary

• Growth Hormone (GH)• Thyroid Stimulating Hormone (TSH)• Adrenocorticotropic Hormone (ACTH)• Gonadotropins (FSH, LH)• Prolactin (PRL)• Melanocyte-stimulating Hormone (MSH)

Growth Hormone (GH)

• Stimulates protein building• Stimulates cell growth (cell size

and number), especially in muscle and bone.

• Also stimulates fat breakdown.

GH GH LevelsLevels

awake sleep

strenuous exercise

hyposecretion of GH

DwarfismDwarfism

Kenadie - worlds smallest girl due to primordial dwarfism

Little People Big World

hypersecretion of GH

GigantismGigantism

Bao Xishun, a 7ft 8.95in herdsman from Inner Mongolia

AcromegalAcromegalyy

hypersecretion of GHhypersecretion of GH

7 ft 1 ¼ inches

Thyroid-Stimulating Thyroid-Stimulating Hormone (TSH)Hormone (TSH)

• Acts on the thyroid gland, stimulating it to release T3 & T4

• These thyroid hormones increase glucose catabolism and body heat production.

• Regulated via negative feedback

Adrenocorticotropic Adrenocorticotropic Hormone (ACTH)Hormone (ACTH)

• Acts on the adrenal cortex, stimulating it to secrete glucocorticoids (e.g., cortisol).

• Helps make glucose from amino acids and fatty acids

• Regulated via negative feedback

The Thyroid Gland

The Thyroid Gland

thyroid

trachea

larynx

Thyroid HormonesThyroid Hormones

• Thyroxine (T4)• Triiodothyronine (T3)Both control metabolic rate and cellular oxidation

• Calcitonin - lowers blood Ca++ levels and causes Ca++ reabsorption in bone

Thyroid gland selectively uptakes iodine to produce T3 & T4

GoiterGoiterLack of iodine in diethyposecretion of T3 & T4

hyposecretion of T3 & T4

CretinismCretinism

MyxedemaMyxedemahyposecretion of T3 & T4

myxedemaAfter thyroid treatment

ExophthalmoExophthalmos-s-

hyperthyroidism

Parathyroid Glands

Parathyroid Glands

Parathyroid Hormone Parathyroid Hormone (PTH)(PTH)

PTH release:1) stimulates osteoclasts to reabsorb bone

Hyperparathyroidism- too much Ca++ drawn out of bone; could be due to tumor

Hypoparathyroidism- most often follow parathyroid gland trauma or after removal of thyroid--- tetany, muscle twitches, convulsions; if untreatedrespiratory paralysis and death

The PancreasThe Pancreas

Pancreas:

• Regulates glucose uptake by cells

• Controlled via negative feedback:

insulin & glucagon

• Blood sugar level: 90 mg/mL

Adrenal Adrenal GlandsGlands

Hormones of the Hormones of the Adrenal MedullaAdrenal Medulla

• Adrenalin (epinephrine): converts glycogen to glucose in liver

• Noradrenalin (norepinephrine): increases blood pressure

(sympathetic nervous system)

• Corticosteroids: glucose levels)

Hormones of the Hormones of the Adrenal CortexAdrenal Cortex

Glucocorticoids- cortisol1. Decrease protein synthesis2. Increase release and use of fatty acids3. Stimulates the liver to produce glucose from non carb’s

Mineralcorticoids- aldosterone1. Stimulates cells in kidney to reabsorb Na+ from filtrate2. Increases water reabsorption in kidneys3. Increases blood pressure

Sex Steroids- small amts (androgens)1. Onset of puberty2. Sex drive

Cushing’s Cushing’s SyndromeSyndrome

Hypersecretion of cortisone; may be caused by an ACTH releasing tumor in pituitary

Symptoms: trunkal obesity and moon face, emotional instability

Treatment: removal of adrenal gland and hormone replacement

Addison’Addison’s s

DiseaseDiseaseHyposecretion of glucocorticoids and mineral corticoids;

Symptoms- wt loss, fatigue, dizziness, changes in mood and personality, low levels of plasma glucose and Na+ levels, high levels of K+

Treatment- corticosteroid replacement therapy

Located anterior to the heart

Produces- thymopoetin and thymosin helps direct maturation and specialization of T-lymphocytes (immunity)

ThymusThymus

Ovaries- produce estrogen and progesteroneresponsible for maturation of the reproductive organs and 2ndary sex characteristics in girls at puberty

GonadsGonads

Female Reproductive System

Testes- produce sperm and testosterone (initiates maturation of male repro organs and 2ndary sex characteristics in boys at puberty)

GonadsGonads

INQUIRY1. A disease in which too much T3 and T4

are produced.2. The posterior pituitary produces which

two hormones and what is their function?

3. What is acromegaly?4. What organ does glucagon target?5. The target tissue for lutenizing hormone

is ____.6. Where are epinephrine and

norepinephrine produced?7. If your adrenal cortex produced low

levels of aldosterone, your urine would be _____?

8. What effect does parathyroid hormone have on your bones?