BIOS 255 Pathophysiology Week 3

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BIOS 255 Pathophysiology Week 3

• Endocrine Glands

–Answer

• Secrete hormones into the bloodstream
• Involve tissues, glands, and hormones Ë

Hypothalamus Ë Anterior pituitary Ë Posterior pituitary Ë End organs

• Hypothalamic- Pituitary- Hormonal Axis

–Answer Ë Connection between hypothalamus, pituitary, and endocrine glands Ë Pituitary (hypophysis) Anterior pituitary (adenohypophysis) Ï Hypothalamus-hypophyseal portal system Posterior pituitary (neurohypophysis)

• Anterior Pituitary as Master Gland

–Answer Ë Growth hormone Somatotropin Ë Prolactin Ë Adrenocorticotropic hormone Ë Thyroid- stimulating hormone Ë 1 / 4

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Follicle-stimulating hormone Ë Luteinizing hormone

• Posterior Pituitary as Master Gland

–Answer Ë Stores hormones Does not produce Ë Antidiuretic hormone Arginine vasopressin Ë Oxytocin

• Endocrine Regulation

–Answer Ï Negative feedback mechanism Ï End-product hormone negatively feeds back to prevent further stimulatory signals Ë Example –Answer thyroid hormones suppress thyroid-stimulating hormone production Ï Receptor activity Ë Upregulation Ë Downregulation

• Upregulation

–Answer Increased receptor sensitivity and number

• Downregulation

–Answer Decreased receptor sensitivity and number

• Endocrine Conditions and Dysfunction

–Answer Ï Hormone deficiency Ë Autoimmune, infection, tumor Ï Hormone excess Ë Tumor, autoimmune, genetic mutation 2 / 4

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Ï Hormone resistance Ë Genetic Ï Hypofunction Ï Hyperfunction Ï Three levels Ë Primary Endocrine gland itself Ë Secondary Abnormal pituitary activity Ë Tertiary Dysfunction of hypothalamic origin

• Endocrine Dysfunction Causes

–Answer Autoimmune –Answer Antibodies target endocrine gland, may causes hypofunction or hyperfunction

• Endocrine Dysfunction Causes

–Answer Neoplasia –Answer Ï Hypofunction or hyperfunction of gland itself or any endocrine tissue the gland affects Ï Some cancers –Answer paraneoplastic disorder cancer cells secrete endocrine hormone

• Endocrine Dysfunction Causes

–Answer Endocrine Disrupting Compounds (EDCs) –Answer Chemicals in environment that can alter endogenous hormone function

• Diagnosis of Endocrine Disorders

–Answer Ï #1 Immunoassays or blood levels of hormones Ï Urinary hormone levels assessed in some cases Ï 3 / 4

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Urinary collection over 24 hours Ï Suppression/stimulation tests Ï CT scan/MRI Ï Ultrasound

• Treatments of Endocrine Disorders

–Answer Ï Hormone replacement therapy Ë Dosage schedules attempt to mimic physiological effects Ë Glucocorticoids, thyroid hormones, sex steroids, ADH most common replacements Ï Suppression of hormone overproduction Ë Medications, surgery, radiation

• Hypopituitarism

–Answer Causes –Answer Ï One or more of the pituitary hormones Ë Pituitary tumor, brain surgery, radiation of brain tumor, congenital disorder Primary adenoma Ï Most common cause Ï Benign neoplasm Ï With growth can compress pituitary tissue and interfere with delivery of hypothala- mic hormones Ë Trauma, ischemia, and infarction can cause sudden loss of pituitary function Pituitary apoplexy Ï Sudden destruction of the pituitary tissue due to infarction or hemorrhage into gland Ï Traumatic brain injury most common cause

• Hypopituitarism

–Answer Sheehan's Syndrome –Answer Develops after childbirth with severe hemorrhage

• Hypopituitarism
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