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Overview of Key Endocrine Organs

Sep 5, 2024

Endocrine Organs Overview

Key Endocrine Organs to Study

  • Thymus
  • Pancreas
  • Pituitary Gland
  • Adrenal Gland
  • Thyroid and Parathyroid

Thymus

  • Consists of follicles with two layers:
    • Cortex: Outer darker layer
    • Medulla: Inner lighter layer

Pituitary Gland (Hypophysis)

  • Connected to the hypothalamus via the infundibulum
  • Sits in the hypophyseal fossa of the sella turcica of the sphenoid bone
  • Two regions:
    • Posterior Pituitary (Neurohypophysis): Pale pink, made of neural tissue
    • Anterior Pituitary (Adenohypophysis): Dark pink, made of glandular epithelium

Thyroid

  • Contains thyroid follicles:
    • Follicular cells: Produce thyroglobulin, stored as colloid
    • Releases T3 and T4 (thyroid hormones)
  • Parafollicular cells: Release calcitonin, regulates blood calcium

Pancreas

  • A mixed organ: heterocrine gland (endocrine and exocrine tissue)
  • Exocrine: Acini, releasing bicarbonate and digestive juices
  • Endocrine: Pancreatic islets (islets of Langerhans)
    • Alpha cells: Release glucagon
    • Beta cells: Release insulin

Adrenal Gland

  • Has multiple layers:
    • Capsule: Connective tissue
    • Cortex: Glandular tissue, releases corticosteroids
    • Medulla: Nervous tissue, releases catecholamines (epinephrine, norepinephrine)
  • Cortex Layers:
    • Zona Glomerulosa: Secretes mineralocorticoids (e.g., aldosterone)
    • Zona Fasciculata: Secretes glucocorticoids (e.g., cortisol)
    • Zona Reticularis: Secretes gonadocorticoids (e.g., androgens)

Hormone Summary

  • Pituitary Hormones:
    • Posterior: ADH, oxytocin
    • Anterior: FSH, LH, ACTH, TSH, prolactin, growth hormone (mnemonic: FLAT PG)
  • Thyroid Hormones: T3, T4, calcitonin
  • Pancreatic Hormones: Insulin, glucagon
  • Adrenal Hormones:
    • Cortex: Mineralocorticoids, glucocorticoids, gonadocorticoids
    • Medulla: Catecholamines

Study Tips

  • Focus first on appearance and structure in your lab:
    • Distinguish organs by their distinct features and tissue types
  • Use mnemonics to remember hormone classes and order of structures
  • Recognize the visual cues: colors, layers, tissue types

Additional Notes

  • The adrenal gland's medulla is distinct from the cortex in both function and appearance.
  • The thymus is easily recognizable by its follicle structure, crucial for understanding AMP2.
  • Prioritize learning the unique features of each gland to distinguish them visually and functionally.

This summary captures the essentials for understanding and identifying key endocrine organs in lab settings, with an emphasis on their structural and functional distinctions.

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