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ENDOCRINE SYSTEM. Hormones. Self-regulating system Production Extremely small amounts Highly potent Affect: Growth Metabolism Behavior Two categories: Lipid (Steroid) Amino acid. Pituitary. Also known as hypophysis Located beneath brain Divided into two lobes: Anterior
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Hormones • Self-regulating system • Production • Extremely small amounts • Highly potent • Affect: • Growth • Metabolism • Behavior • Two categories: • Lipid (Steroid) • Amino acid
Pituitary • Also known as hypophysis • Located beneath brain • Divided into two lobes: • Anterior • Releases six hormones • Posterior • Releases two hormones
Thyroid and Parathyroids • Thyroid gland • Located on either side of larynx and upper trachea • Two lobes • Secretes mixture of hormones • Parathyroid glands • Located at posterior surface of thyroid • Affect calcium metabolism
Adrenal Glands • Hormones produced involved in body’s response to stress • Located atop each kidney • Divided into two regions • Outer cortex produces: • Steroid hormones • Cortisol • Aldosterone • Sex hormones • Inner medulla produces • Epinphrine • Norepinephrine
Pancreas • Islet cells produce two hormones: • Insulin • Increases cellular use of glucose • Decreases sugar levels in blood • Glucagon • Decreases cellular use of glucose • Increases sugar levels in blood
Other Endocrine Tissues • Thymus • Secretes thymosin • Gonads • Secrete sex hormones • Prostaglandins • Group of hormones produced by many cells • Variety of effects • Uterine contractions • Inflammatory response • Vasomotor activities
Clinical Aspects of Endocrine System • Endocrine diseases result from: • Hypersecretion • Hyposecretion • Secretion at wrong time • Failure of target tissue to respond • Causes may originate: • In gland itself • With hypothalamus or pituitary failing to release proper amount of hormone stimulators
Pituitary • Pituitary adenoma usually increases secretion of growth hormone • Excess in children causes gigantism • Excess in adults causes acromegaly • Treatment • Surgery • Drugs to reduce hormone level in blood
Pituitary (con’t) • Panhypopituitarism • Hypofunction of pituitary • Caused by tumor or interruption of gland’s blood supply • Widespread effects • Lack of ADH • Results in diabetes insipidus • Kidneys with diminished ability to conserve water • Symptoms include: • Polyuria • Polydipsia
Thyroid • Deficiency of thyroid hormone causes: • In infants • Physical retardation • Mental retardation • Congenital hypothyroidism • In adults • Myxedema • Hyperthyroidism • Common form is Graves disease • May result in goiter (enlarged thyroid) • Not always results from thyroid malfunction
Parathyroids • Overactivity causes high level of calcium in blood • Calcium obtained from bones • Possible development of kidney stones • Underactivity results in decreased calcium • May cause: • Tingling • Numbness • Tetany
Adrenals • Addison disease = hypofunction of adrenal cortex • Caused by: • Autoimmune destruction of gland • ACTH deficiency • Results in: • Water loss • Low blood pressure • Electrolyte imbalance • Weakness • Nausea • Increase of brown pigmentation
Adrenals (cont’d) • Cushing syndrome = excess of adrenal cortisol hormones • Caused by: • Therapeutic administration of steroid hormones • Tumor • Results in: • Moon-shaped face • Localized obesity • Weakness • Hirsutism • Fluid retention
Pancreas and Diabetes • Diabetes mellitus • Most common endocrine disorder • Failure to use glucose effectively • Excess glucose causes hyperglycemia • Two types: • Type 1 (juvenile-onset or insulin-dependent) • Type 2 (adult-onset or non-insulin dependent)
Type 1 Diabetes • Usually appears in children and teenagers • Caused by failure of pancreatic islets to produce insulin • For proper management: • Monitor blood sugar levels • Give insulin in divided doses • Regulate diet
Type 2 Diabetes • Initiated by cellular resistance to insulin • May result in: • Metabolic syndrome • Hypoglycemia • Insulin shock • Diagnosed by measuring levels of glucose in blood plasma • Most cases linked to obesity • Another form is gestational diabetes mellitus