Lecture 01, 2

• What is the importance of the endocrine system?

  It regulates adaptation to internal and external changes
• What are the primary endocrine glands?

  Pineal, hypothalamus, thyroid, parathyroid
• What are the secondary endocrine glands?

  Heart, gastrointestinal tract, liver, kidney, skin
• What is the physiological mechanism of hormone synthesis?

  Hormones are synthesised and secreted by glands
• How do hormones act in the body?

  They bind to specific receptors on target cells
• What is the hypothalamus-pituitary axis?

  It regulates hormone release from the pituitary gland
• What hormones are released by the hypothalamus?

  GHRH, TRH, CRH, GnRH, PRF, SS, DA
• What is the function of growth hormone?

  It promotes growth and metabolism in tissues
• What are the thyroid hormones?

  T3, T4, and calcitonin
• What distinguishes exocrine glands from endocrine glands?

  Exocrine glands secrete into ducts; endocrine does not
• What are neurohormones?

  Hormones released from neurons into the blood
• What is the role of autocrine signaling?

  It acts on the same cells that produce it
• What is paracrine signaling?

  It acts on adjacent cells through diffusion
• What is the function of the pineal gland?

  It secretes melatonin for biological clock regulation
• What does the adrenal gland secrete?

  Aldosterone, cortisol, and androgens
• What are the types of hormones based on their structure?

  Amine, peptide, and steroid hormones
• How are peptide hormones secreted?

  By exocytosis and are free in plasma
• How do lipophilic hormones act?

  They bind to intracellular receptors in the cytosol
• What is the role of T3 in the body?

  It regulates metabolic activity and energy expenditure
• What is hypothyroidism?

  Deficiency in T3 and T4 secretion
• What are the symptoms of hyperthyroidism?

  High metabolic rate, restlessness, and weight loss
• What are the functions of growth hormone (GH)?

  • Promotes growth of tissues
  • Increases protein synthesis
  • Mobilises fatty acids
  • Decreases glucose utilisation
• What are the effects of thyroid hormones (T3 and T4)?

  • Regulate metabolic rate
  • Influence body temperature
  • Affect cardiac rate and contractility
  • Impact respiratory drive
• What is the feedback loop in the hypothalamus-pituitary axis?

  • Hypothalamus releases hormones
  • Anterior pituitary secretes hormones
  • Hormones regulate target glands
  • Feedback regulates hormone levels
• What are the differences between hydrophilic and lipophilic hormones?

  Hydrophilic hormones:

  • Bind to plasma membrane receptors
  • Secreted by exocytosis
  • Free in plasma

  
  

  Lipophilic hormones:

  • Bind to intracellular receptors
  • Secreted by diffusion
  • Protein-bound in plasma
• What are the daily and lifetime patterns of GH secretion?

  • Daily secretion varies with sleep and activity
  • Lifetime secretion decreases with age
  • GH is crucial for tissue repair and growth
• What are the roles of the anterior pituitary hormones?

  • GH: Metabolism and growth
  • TSH: Stimulates thyroid hormone secretion
  • ACTH: Stimulates cortisol secretion
  • Prolactin: Milk production
  • Gonadotropic hormones: Stimulate gonads
• What are the effects of T3 on GH synthesis?

  • Increases mRNA content of GH gene
  • Directs synthesis of growth hormone
  • Enhances overall metabolic activity
• What are the symptoms of hypothyroidism?

  • Low metabolic rate
  • Lethargy and inactivity
  • Bradycardia and cold intolerance
  • Weight gain despite decreased appetite
• What are the symptoms of hyperthyroidism?

  • High metabolic rate
  • Restlessness and tachycardia
  • Heat intolerance
  • Weight loss despite increased appetite