1 ENDOCRINE SYSTEM

2Hormones Self-regulating system Production –Extremely small amounts –Highly potent Affect: –Growth –Metabolism –Behavior Two categories: –Lipid (Steroid) –Amino acid

3 Endocrine Glands

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8 Pituitary Also known as hypophysis Located beneath brain Divided into two lobes: –Anterior Releases six hormones –Posterior Releases two hormones

9 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

10 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

11Pancreas 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

12 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

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15 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

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17 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

18 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

19Thyroid 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

20 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

21Adrenals 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

22 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

23 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)

24 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

25 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

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