Overview
This lecture reviews the endocrine system, focusing on major organs, hormone functions, medical terminology, common disorders, diagnostic procedures, and treatments relevant to the endocrine glands.
Major Endocrine Organs and Their Locations
- Endocrine system includes hypothalamus, pituitary, pineal, thyroid, parathyroid, thymus, adrenal glands, pancreas, testes, and ovaries.
- Hypothalamus and pituitary are at the brain's base; thyroid and parathyroids are in neck; thymus in chest; adrenals on kidneys; pancreas in abdomen; testes/ovaries in pelvis.
Hormone Production and Regulation
- Endocrine cells secrete hormones that travel in blood to bind specific target cell receptors and regulate body functions.
- Hypothalamus controls pituitary function by producing hormones; pituitary (master gland) releases hormones that affect many organs.
- Pineal gland secretes serotonin (day) and melatonin (night) to regulate sleep and mood.
Key Glands and Their Hormones
- Anterior pituitary secretes GH, ACTH, TSH, PRL, FSH, LH.
- Posterior pituitary stores/releases oxytocin and ADH made by hypothalamus.
- Thyroid produces T3 (triiodothyronine), T4 (thyroxine) for metabolism, and calcitonin for bone growth.
- Parathyroids secrete PTH to raise blood calcium.
Hormone Functions and Interactions
- GH affects growth; ACTH stimulates adrenal cortisol; TSH stimulates thyroid; PRL aids milk production; FSH/LH regulate reproduction.
- Calcitonin and PTH are antagonists: calcitonin lowers, PTH raises blood calcium.
- Pancreas produces glucagon (raises glucose), insulin (lowers glucose), somatostatin (inhibits both).
Key Endocrine Disorders
- GH excess: gigantism (children), acromegaly (adults); deficiency: dwarfism.
- Prolactin excess causes galactorrhea and menstrual issues in women, impotence in men.
- T3/T4 excess: hyperthyroidism (e.g., Graves disease), T3/T4 deficiency: hypothyroidism, cretinism (infants).
- PTH imbalance: hypo/hyperparathyroidism affects calcium, causing cramps or kidney stones.
- Adrenal cortex hypo/hyperfunction: Addison's (deficiency), Cushing syndrome (excess), Conn syndrome (aldosterone excess).
- Chromaffin cell tumors (pheochromocytoma) cause severe hypertension.
Diabetes Mellitus and Related Terms
- Diabetes mellitus: high blood glucose due to insulin issues, presents with polydipsia, polyuria, polyphagia.
- Diagnosis via fasting/random glucose, HbA1c; managed with diet, exercise, oral meds, insulin therapy.
- Hypoglycemia: low blood sugar, treated with fast-acting carbs.
- Diabetic ketoacidosis: serious complication of uncontrolled diabetes.
Diagnostic and Therapeutic Procedures
- Pituitary: hormone blood/urine tests, MRI/CT, visual field, surgery, radiation, hormone replacement.
- Thyroid: hormone levels, scan, biopsy, ultrasound, anti-thyroid meds, replacement therapy, radioactive iodine.
- Parathyroid: calcium-mimicking drugs or supplements, PTH replacement.
- Thymus: stem cell transplant, surgery, radiation for tumors.
- Adrenal: hormone levels, imaging, steroid/mineralocorticoid therapy, tumor surgery, radiation.
- Diabetes: glucose testing, oral hypoglycemics, insulin, education on injection/monitoring.
Key Terms & Definitions
- Endocrine — glands secreting hormones into the bloodstream.
- Hormone — chemical messenger regulating bodily processes.
- Pituitary gland — master gland controlling many endocrine organs.
- Hypothalamus — brain region regulating pituitary.
- Calcitonin — hormone decreasing blood calcium.
- Parathyroid hormone (PTH) — increases blood calcium.
- Insulin — lowers blood glucose by cell uptake.
- Glucagon — raises blood glucose by liver glycogen breakdown.
- Gigantism/Dwarfism/Acromegaly — effects of GH imbalance.
- Addison/Cushing/Conn syndrome — adrenal cortex disorders.
- Diabetes mellitus — chronic high blood sugar.
Action Items / Next Steps
- Review textbook figures and diagrams of endocrine organs.
- Memorize major hormones, their sources, and effects.
- Practice medical abbreviations and hormone-related terminology.
- Prepare for a quiz on endocrine disorders and diagnostic procedures.