The Endocrine System

Major Endocrine Organs

Endocrine Organs of the Brain pineal gland hypothalamus Major Regions of the Brain pituitary gland

Pineal Gland Produces melatonin 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

The Pituitary Gland

Posterior Pituitary

Hormones of the Posterior Pituitary Antidiuretic Hormone (ADH) Oxytocin

Oxytocin (+ feedback) loop oxytocin

Anterior 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 Levels awake sleep strenuous exercise

Dwarfism hyposecretion of GH Little People Big World Kenadie - worlds smallest girl due to primordial dwarfism

Gigantism hypersecretion of GH Bao Xishun, a 7ft 8.95in herdsman from Inner Mongolia

Acromegaly hypersecretion of GH 7 ft 1 ¼ inches

Thyroid-Stimulating 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 Hormone (ACTH) Acts on the adrenal cortex, stimulating it to secrete glucocorticoids (e.g., cortisol). Helps make glucose from amino acids and fatty acids

The Thyroid Gland larynx thyroid trachea

Thyroid Hormones Thyroid gland selectively uptakes iodine to produce T3 & T4 Thyroxine (T4) Triiodothyronine (T3) Both control metabolic rate and cellular oxidation Calcitonin - lowers blood Ca2+ levels and causes Ca2+ reabsorption in bone

Goiter Lack of iodine in diet hyposecretion of T3 & T4

Cretinism hyposecretion of T3 & T4

Myxedema hyposecretion of T3 & T4 After thyroid treatment myxedema

Exophthalmos- hyperthyroidism

Parathyroid Glands

Parathyroid Hormone (PTH) PTH release: stimulates osteoclasts to reabsorb bone

The Pancreas

Pancreas: Regulates glucose uptake by cells Controlled via negative feedback: insulin & glucagon Blood sugar level: 90 mg/mL

Adrenal Glands

Cushing’s Syndrome Hypersecretion of cortisone; may be caused by a releasing tumor in pituitary Symptoms: trunkal obesity and moon face, emotional instability Treatment: removal of adrenal gland and hormone replacement

Addison’s Disease Hyposecretion 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 Addison’s Disease is characterized by the withering of the adrenal glands, which produce adrenaline and other hormones. Symptoms include fatigue, dizziness, muscle weakness, weight loss, difficulties standing up, nausea, sweating and changes in mood and personality. Autoimmune disease

Thymus Located anterior to the heart Produces- thymopoetin and thymosin helps direct maturation and specialization of T-lymphocytes (immunity)

Gonads Ovaries- produce estrogen and progesteroneresponsible for maturation of the reproductive organs and 2ndary sex characteristics in girls at puberty ovary

Female Reproductive System

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

INQUIRY A disease in which too much T3 and T4 are produced. The posterior pituitary produces which two hormones and what is their function? What is acromegaly? What organ does glucagon target? The target tissue for gonadotropins is ____. Where are epinephrine and norepinephrine produced? What effect does parathyroid hormone have on your bones?