Rapid Recall

1. The Master Connections

  • Hypothalamus →\rightarrow Anterior Pituitary: Connected via the Hypophyseal Portal System (Blood vessels). Releasing/inhibiting hormones travel here.
  • Hypothalamus →\rightarrow Posterior Pituitary: Connected via Direct Neural Regulation (Axons). Oxytocin and ADH are transported here for storage.

2. The Balancing Acts (Antagonistic Hormones)

  • Calcium (Ca2+Ca^{2+}): PTH (Hypercalcemic - Increases blood calcium) vs. Thyrocalcitonin / TCT (Hypocalcemic - Decreases blood calcium).
  • Glucose: Glucagon (Hyperglycemic - Increases) vs. Insulin (Hypoglycemic - Decreases).
  • Water/Salt: ADH/Vasopressin (Water retention in kidneys) & Aldosterone (Sodium Na+Na^+ retention and K+K^+ excretion).

3. Chemical Nature & Receptors

  • Steroids (Lipid soluble): Estrogen, Cortisol, Testosterone, Progesterone →\rightarrow Bind to Intracellular/Nuclear Receptors →\rightarrow Regulate gene expression.
  • Peptides/Proteins (Water soluble): Insulin, Glucagon, FSH, LH, Pituitary hormones →\rightarrow Bind to Membrane Receptors →\rightarrow Generate 2nd Messengers (like cAMP, IP3IP_3, Ca2+Ca^{2+}).
  • Amino-Acid Derivatives: Epinephrine, Norepinephrine (Adrenaline/Noradrenaline).
  • Iodothyronines: T3T_3, T4T_4 (Act similarly to steroids using intracellular receptors).

4. Disorder Keywords to Memorize

  • Graves' Disease: Autoimmune Hyperthyroidism (Symptoms: Exophthalmos / bulging eyes, weight loss).
  • Addison's Disease: Adrenal Cortex failure / Hyposecretion (Symptoms: Altered carbohydrate metabolism, extreme weakness).
  • Acromegaly: Excess Growth Hormone (GH) in adults (Symptoms: Severe facial/bone disfigurement).
  • Diabetes Insipidus: ADH deficiency (Symptoms: Intense thirst, massive loss of dilute urine).
  • Diabetes Mellitus: Insulin deficiency/resistance (Symptoms: Glycosuria, Ketonuria).
  • Cretinism: Hypothyroidism during pregnancy (Symptoms: Stunted growth, mental retardation in baby).