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The Endocrine SystemGlands & Hormones

Chapter 12Chapter 12

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Hormones Chemical messengers that have specific effects on

certain cells or organs in the body Released directly into the bloodstream Regulate growth, metabolism, reproduction &

behavior Some effect MANY tissues: growth hormone,

thyroid hormone & insulin Some effect SPECIFIC tissues: Thyroid Stimulating

Hormone (TSH) & Adrenocorticotropic Hormone (ACTH)

Specific tissues are called “Target Tissues”

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Endocrine Glands, Their Hormones & Their Functions

Pituitary Gland

Thyroid GlandThyroid Gland

Growth Hormone (GH) Growth of all body tissue

Thyroid Stimulating Hormone (TSH) Stimulates thyroid gland to produce

thyroid hormones

Thyroxine Increases metabolic rate influencing

both physical & mental activities required for normal growth

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Parathyroids

Pancreas

Parathyroid Hormone Regulates exchange of calcium

between blood & bones; increases calcium level in blood

Insulin Aids transport of glucose into

cells; required for cellular metabolism of foods, especially glucose; decreases blood sugar levels

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Testes

Ovaries

Testosterone Stimulates growth & development of

male sexual organs (testes & penis) plus development of secondary sex characteristics, such as hair growth on face & body and deepening of voice; stimulates maturation of sperm cells

Estrogen Stimulates growth of primary female

sexual organs (uterus & fallopian tubes) plus development of secondary sex characteristics, such as breasts, plus changes in the pelvis to a broader shape

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Disorders Associated with Endocrine Dysfunction

Hormone Hypersecretion Hyposecretion

Growth Gigantism Dwarfism

Thyroid Grave’s Disease Cretinism Myxedema

Insulin Hypoglycemia Hyperglycemia

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Hormones Used for Treatment

1. Growth Hormone – for children with a deficiency in GH

2. Insulin – for diabetes3. Adrenal Steroids – for relief of inflammation of

rheumatoid arthritis, lupus and asthma4. Epinephrine – stimulates heart muscle, treats

asthma attacks & acute allergic reactions5. Thyroid Hormones – for cretinism in children (lack

of growth & mental development) and myxedema in adults (mentally & physically sluggish)

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Hormones & Stress

Physical injury, disease, emotional distress/anxiety and even pleasure involves a reponse from the endocrine system

Hormones can help the body meet stressful situations

Overproduction, however, can be harmful and lead to: high blood pressure, heart disease, ulcers & headaches

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Aging and the Endocrine System

Loss of muscle and bone tissue Adult Onset (Type 2) Diabetes from the

decrease of insulin secretion Decline in sex hormones Decrease in bone mass leading to Osteoporosis Decrease in growth hormone