THE ENDOCRINE SYSTEMTHE “HEART” OF HEALTH

DEFINITIONS

• THE GLANDS AND PARTS OF GLANDS THAT PRODUCE ENDOCRINE SECRETIONS, HELP TO INTEGRATE AND CONTROL BODILY METABOLIC ACTIVITY, AND INCLUDE ESPECIALLY THE PITUITARY, THYROID, PARATHYROIDS, ADRENALS, ISLETS OF LANGERHANS, OVARIES, AND TESTES.

HTTP://WWW.MERRIAM-WEBSTER.COM/

• (1) THE BODILY SYSTEM THAT CONSISTS OF THE ENDOCRINE GLANDS THAT RELEASE THEIR SECRETIONS (HORMONES) INTO THE BLOODSTREAM TO REACH AND ACT ON TARGET CELLS OF SPECIFIC ORGANS.

• (2) THE ANIMAL SYSTEM RESPONSIBLE FOR THE PRODUCTION AND SECRETION OF HORMONES THAT AID IN CONTROLLING THE BODILY METABOLIC ACTIVITY, AS WELL AS SERVE AS CHEMICAL MESSENGERS THAT ALLOW CELLS TO COMMUNICATE WITH ONE ANOTHER.

HTTP://WWW.BIOLOGY-ONLINE.ORG/DICTIONARY

FUNCTIONS

THE ENDOCRINE SYSTEM MAINTAINS HOMEOSTASIS BY RELEASING CHEMICALS CALLED HORMONES, AND IT CONTROLS PROLONGED OR CONTINUOUS

PROCESSES SUCH AS GROWTH AND DEVELOPMENT, REPRODUCTION AND METABOLISM.

HORMONES

CHEMICAL MESSENGERS CREATED BY ENDOCRINE CELLS THAT ARE SECRETED

INTO BODY FLUIDS THAT TRIGGER SPECIFIC CHANGES IN OTHER CELLS IN THE BODY. MESSENGERS ENTER THE

CIRCULATORY SYSTEM AND TRAVEL TO EVERY PART OF THE BODY BUT ONLY AFFECT TARGET CELLS OR ORGANS

HOW DO HORMONES WORK?

AS HORMONES TRAVEL NEARLY EVERYWHERE THROUGH THE BODY ONLY SPECIFIC TARGET CELLS HAVE THE APPROPRIATE PROTEIN RECEPTORS THAT

THE HORMONE CAN ATTACH TO. WITHOUT THE SPECIFIC RECEPTOR PRESENT THE HORMONE HAS NO EFFECT ON THE CELL. THINK OF IT LIKE A LOCK AND KEY; EACH CELL HAS RECEPTORS(LOCKS) THAT CAN ONLY BE ACTED UPON WITH THE RIGHT HORMONE

(KEY).

TYPICAL HORMONAL INFLUENCES

1. CHANGES IN PLASMA MEMBRANE PERMEABILITY OR ELECTRICAL STATE

2. SYNTHESIS OF PROTEINS OR REGULATORY MOLECULES IN A CELL

3. ACTIVATE OR INACTIVATE AN ENZYME IN A CELL

4. STIMULATION OF MITOSIS

5. PROMOTE SECRETORY ACTIVITY

THE HORMONE EFFICIENCY (TRAVELING THROUGH CIRCULATORY

SYSTEM TO DESIRED RECIPIENTS) AND CONCENTRATION IN BLOOD VARIES

DEPENDING ON THE RATE RELEASED, EFFICIENCY OF FEEDBACK

MECHANISMS, AND CLEARANCE AVAILABLE. (BAUER,2005)

TWO MECHANISMS OF CHANGE IN CELLS

DIRECT GENE ACTIVATION

OR

SECOND MESSENGER SYSTEM

SECOND MESSENGER SYSTEM

SECOND MESSENGER SYSTEM CANNOT ENTER TARGET CELLS SO INSTEAD IT

BINDS TO EXTERIOR MEMBRANE. THIS TRIGGERS EVENTS INSIDE THE CELL

RELEASING AN ENZYME WHICH HAS THE DESIRED EFFECT ON THE SPECIFIC CELL.. ONE HORMONE CAN HAVE MULTIPLE SECOND MESSENGERS.

DIRECT GENE ACTIVATION

STEROID HORMONES AND THYROID HORMONES ARE THE

ONLY HORMONES THAT USE DIRECT GENE ACTIVATION.

HORMONES ENTER NUCLEUS, BIND TO CELL HORMONE

RECEPTOR AND DNA, CREATES RNA,, THEN IS SYNTHESIZED INTO

NEW PROTEINS.

MAJOR ORGANS OF ENDOCRINE SYSTEM

• PINEAL GLAND

• HYPOTHALAMUS-

• PITUITARY GLAND

• THYROID GLAND

• PARATHYROID GLANDS

• ADRENAL GLANDS

• PANCREAS

• OVARIES IN FEMALES

• TESTES IN MALES

HYPOTHALAMUS

• MOST IMPORTANT ENDOCRINE GLAND, OFTEN CALLED THE “MASTER

GLAND”

• CONTROLS HYPOPHYSIS (PITUITARY GLAND) WHICH GIVES IT CONTROL OF

MOST GLANDS IN THE ENDOCRINE SYSTEM

• CONTROLS AUTONOMIC NERVOUS SYSTEM WHICH IS THE PART THAT

CONTROLS HOMEOSTASIS

PITUITARY GLAND• LOCATED IN BRAIN

• MASTER CONTROL GLAND

• HORMONES ARE CONTROLLED BY HYPOTHALAMUS BY RELEASING OR INHIBITING HORMONES

• CREATES OXYTOCIN WHICH STIMULATES MUSCLE CHANGES IN CHILDBIRTH IN FEMALES, DURING SEXUAL INTERCOURSE, AND FOR BREAST FEEDING

• CREATES ANTIDIURETIC HORMONE WHICH INHIBITS URINE PRODUCTION. KIDNEYS ABSORB MORE WATER DECREASING URINE VOLUME BUT INCREASING BLOOD VOLUME. CAN ALSO INCREASE BLOOD PRESSURE BY RESTRICTING ARTERIES.

• CREATES TROPIC HORMONES THAT TRIGGER OTHER ENDOCRINE ORGANS TO SECRETE THEIR HORMONES AFFECTING VARIOUS ORGANS AND FUNCTIONS.

• CREATES GROWTH HORMONES WHICH AFFECT SKELETAL MUSCLES AND BONE GROWTH, ALSO BREAKS DOWN FATS FOR ENERGY AND SPARING GLUCOSE MAINTAINING BALANCED BLOOD SUGAR LEVELS.

DISORDERS OF PITUITARY GLAND

• DIABETES INSIPIDUS IS CAUSED BY HYPERSECRETION OF ADH CAUSING EXTREME THIRST

• PITUITARY DWARFISM IS CAUSED BY HYPOSECRETION OF GROWTH HORMONES DURING CHILDHOOD LEADING TO A PROPORTIONATE YET MINIATURE ADULT.

• GIGANTISM IS CAUSED BY HYPERSECRETION OF GROWTH HORMONES AFTER YOUTH LEADING TO OVERSIZED HUMANS UP TO TEN FT TALL.

THYROID GLAND

• LOCATED IN BASE OF THROAT

• CREATES THROID HORMONE WHICH IS THE BODYS MAIN METABOLIC HORMONE

• CREATES CALCITONIN WHICH REDUCES CALCIUM SUPPLY IN BLOOD TO BE DEPOSITED IN BONES.

DISORDERS OF THE THYROID GLAND

• GOITERS ARE AND ENLARGED THYROID GLAND CAUSED BY LACK OF IODINE

• GRAVES DISEASE IS CAUSED BY HYPERTHYROIDISM WHICH GENERALLY RESULTS FROM A TUMOR OF THE THYROID GLAND

PARATHYROID GLANDS

• FOUND IN POSTERIOR OF THYROID GLAND USUALLY CONSISTING OF FOUR PARATHYROIDS

• CREATES PARATHYROID HORMONE WHICH IS THE MOST IMPORTANT REGULATOR OF CALCIUM IONS IN BLOOD.

DISORDERS OF PARATHYROID GLANDS

• TETANY IS UNCONTROLLABLE MUSCLE SPASMS CAUSED BY BLOOD CALCIUM LEVELS BEING TO LOW. THIS CAUSES NEURONS TO BECOME IRRITABLE AND OVERACTIVE.

• SEVERE PARATHYROIDISM CAN CAUSE CAUSE WEAK AND FRAGILE BONES

ADRENAL GLANDS

• BEAN SHAPED AND FOUND AT THE TOP OF THE KIDNEYS

• STRUCTURAKKY AND FUNCTIONALLY TWO ORGANS,

• ADRENAL CORTEX PRODUCES 3 MAJOR STEROID HORMONES: CORTICOL STEROIDS,

MINERALOCORTICOIDS, GLUCOCORTICOIDS, AND SEX HORMONES

• ADRENAL MEDULLA CREATES NOREPINEPRIN, EPINEPHRINE, AND ADRENALIN

DISORDERS OF THE ADRENAL GLAND

• ADDISONS DISEASE

• HYPERALDOSTERONISM

• CUSHINGS SYNDROME

• MASCULINIZATION

PANCREATIC ISLETS

• LOCATED ON PANCREAS

• MILLIONS OF ISLES LOCATED IN SMALL CLUMPS SEPARATED BY EXOCRINE

SYSTEM CELLS. EACH CLUSTER ACTS AS AN ORGAN WITHIN AN ORGAN

• TWO MAIN HORMONES ARE INSULIN AND GLUCAGON

DISORDERS OF THE PANCREATIC ISLES

• DIABETES MELLITUS IS CAUSED BY LACK OF INSULIN WHICH LEADS TO HIGH GLUCOSE LEVELS WHICH FLOOD THE BODY

• CAUSES EXCESSIVE URINATION AS BODY TRIES TO FLUSH GLUCOSE

• CAUSES EXCESSIVE THIRST FROM WATER LOSS

• HUNGER DUE TO LACK OF BEING ABLE TO USE SUGARS AND THE LOSS OF FAT

PINEAL GLAND

• SMALL CONE SHAPED GLAND IN THE BRAIN

• MOST MYSTERIOUS ENDOCRINE GLAND

• ONLY KNOWN HORMONE SECRETED IN ANY MEASURABLE AMOUNT IS MELATONIN

WHICH IS A SLEEP TRIGGER AND RESPONSIBLE FOR ESTABLISHING BODYS

DAY-NIGHT CYCLE.

• IN SOME ANIMALS MELATONINE REGULATES MATING BEHAVIOR AND

RHYTHMS

• LOCATED POSTERIOR TO STERNUM IN UPPER THORAX

• IS LARGE IN CHILDREN AND GETS SMALLER WITH AGE

• PRODUCES THYMOSIN WHICH IS RESPONSIBLE FOR REGULATING

WHITE BLOOD CELLS AND IMMUNE RESPONSE

GONADS

• OVARIES IN FEMALES AND TESTES IN MALES.

• OVARIES PRODUCE 2 STEROID HORMONES: ESTROGENS AND PROGESTERONE

• TESTES PRODUCE ANDROGENS, THE MOST IMPORTANT IS TESTOSTERONE