endocrine

Anatomy and Physiology of the Endocrine System

  • Endocrine Glands: Include pineal, thymus, hypothalamus, pituitary, thyroid, parathyroid, pancreas, ovaries, testes, and placenta.

  • Hormone Actions: Hormones exert influence on targeted organs.

  • Negative Feedback: Increased activity leads to decreased hormone release to maintain homeostasis.

Endocrine Glands and Their Functions

  • Pituitary Gland:

    • Anterior: Regulates other endocrine glands, secretes growth hormone.

    • Posterior: Secretes oxytocin and antidiuretic hormone (ADH).

  • Thyroid Gland:

    • Produces T3 (triiodothyronine) and T4 (thyroxine) for metabolism.

    • Calcitonin regulates calcium levels.

  • Adrenal Glands:

    • Cortex: Produces mineralocorticoids (aldosterone), glucocorticoids (cortisol), sex hormones.

    • Medulla: Releases epinephrine and norepinephrine.

  • Pancreas:

    • Produces insulin (lowers blood glucose) and glucagon (raises blood glucose).

  • Ovaries:

    • Produce estrogen and progesterone.

  • Testes:

    • Produce testosterone.

Hormonal Effects on Target Organs

  • ADH: Increases water reabsorption in kidneys.

  • Oxytocin: Stimulates milk ejection and uterine contractions.

  • Insulin/Glucagon: Controls blood sugar levels.

  • Thyroid Hormones: Regulate metabolic rate and energy.

  • Parathyroid Hormone (PTH): Increases blood calcium levels.

  • Mineralocorticoids: Manage electrolyte balance.

Disorders of the Endocrine System

  • Diabetes Insipidus: Caused by lack of ADH, leading to severe diuresis.

  • Ketoacidosis: Resulting from extreme insulin deficiency, leading to metabolic acidosis.

  • Acromegaly/Gigantism: Caused by excess growth hormone, leading to abnormal growth.

  • Hypothyroidism/Hyperthyroidism: Under or overactivity of thyroid hormones, affecting metabolism.

  • Cushing's Syndrome/Addison's Disease: Disorders of adrenal hormone production.

Diagnostic Tests for Diabetes

  • HbA1c Test: Reflects average blood glucose over 8-12 weeks.

  • Fasting Blood Glucose: >125 mg/dL indicates diabetes.

  • Oral Glucose Tolerance Test: Assesses body's glucose management (results > 200 mg/dL indicate diabetes).

Management of Diabetes Mellitus

  • DM Type 1: Requires insulin therapy. Symptoms: polyuria, polydipsia, weight loss.

  • DM Type 2: Associated with insulin resistance; often linked to obesity.

  • Complications: Long-term risks include nephropathy, neuropathy, retinopathy, and cardiovascular disease.

  • Management: Includes diet control, exercise, and medications like insulin and oral hypoglycemics.