Endocrine System: Medical Terminology Study Guide

Endocrine System

Overview of the Endocrine System

The endocrine system is a network of glands that secrete hormones directly into the bloodstream, regulating various physiological processes. These hormones influence metabolism, growth, development, and help maintain homeostasis. The main endocrine glands include the pituitary, thyroid, parathyroid, adrenal, pancreas (islets of Langerhans), gonads (ovaries and testes), and thymus.

• Function: Hormones released by these glands regulate metabolic activities, growth, and development.

• Interaction: The endocrine system works closely with the nervous system to maintain homeostasis.

Example: Disorders of the endocrine system can have widespread effects due to the systemic action of hormones.

Endocrine Glands and Their Hormones

Each endocrine gland produces specific hormones that regulate body functions and other glands.

• Pituitary Gland (Hypophysis): Located at the base of the brain, often called the "master gland." Divided into anterior and posterior lobes.

  • Anterior Lobe Hormones:

    • GH (Growth Hormone): Regulates growth of tissues and bones.

    • ACTH (Adrenocorticotropic Hormone): Stimulates adrenal cortex to produce corticosteroids.

    • TSH (Thyroid Stimulating Hormone): Stimulates thyroid gland to produce thyroid hormones.

    • PRL (Prolactin): Stimulates milk production in mammary glands.

  • Posterior Lobe Hormones:

    • ADH (Antidiuretic Hormone): Promotes water reabsorption in kidneys, reducing urine output.

    • Oxytocin: Stimulates uterine contractions during labor and milk ejection during breastfeeding.

• Islets of Langerhans (Pancreas): Secrete insulin (lowers blood glucose) and glucagon (raises blood glucose).

• Adrenal Medulla: Secretes epinephrine (adrenaline), which increases heart rate and respiration during stress.

Example: A patient with diabetes mellitus may require insulin to regulate blood glucose levels.

Medical Terminology: Word Parts

Understanding medical terminology is essential for describing endocrine system structures, functions, and disorders.

• Combining Forms:

  • aden/o, adrenal/o: adrenal glands

  • endocrin/o: endocrine

  • pituitar/o: pituitary gland

  • thyr/o, thyroid/o: thyroid gland

• Suffixes:

  • -drome: run, running (as in syndrome)

Disease and Disorder Terms

Endocrine disorders can be described using terms built from word parts or traditional names.

• Terms Built from Word Parts:

  • Acromegaly: Enlargement of extremities due to excessive growth hormone.

  • Adrenalitis: Inflammation of the adrenal glands.

  • Hyperglycemia: Excessive sugar in the blood.

  • Hypothyroidism: Deficient thyroid activity.

  • Parathyroidoma: Tumor of a parathyroid gland.

• Terms Not Built from Word Parts:

  • Addison Disease: Deficiency in adrenal cortex hormones.

  • Cushing Syndrome: Excessive production of adrenal cortisol.

  • Diabetes Mellitus (DM): Underactivity of insulin, resulting in hyperglycemia.

  • Gigantism: Excessive growth hormone secretion during childhood.

  • Graves Disease: Excessive thyroid hormone production (hyperthyroidism).

  • Goiter: Enlargement of the thyroid gland.

  • Metabolic Syndrome: Cluster of symptoms increasing risk for diabetes mellitus.

  • Tetany: Muscle spasms due to low calcium levels.

Example: A patient with Graves disease may present with exophthalmos and elevated thyroid hormone levels.

Surgical Terms

Surgical procedures are often named using word parts that describe the excision of specific glands.

• Adrenalectomy: Excision of the adrenal gland.

• Pancreatectomy: Excision of the pancreas.

• Parathyroidectomy: Excision of a parathyroid gland.

• Thyroidectomy: Excision of the thyroid gland.

Example: Adrenalectomy may be performed to remove a tumor from the adrenal gland.

Diagnostic Terms

Diagnostic tests are used to assess endocrine function and monitor disorders.

• Radioactive Iodine Uptake (RAIU): Nuclear medicine scan to visualize thyroid function.

• Thyroid Sonography: Ultrasound imaging of the thyroid gland.

• Fasting Blood Sugar (FBS): Measures blood glucose levels after fasting.

• Glycosylated Hemoglobin (HbA1C): Test to diagnose and monitor diabetes mellitus by measuring average blood glucose over several months.

• Thyroid-Stimulating Hormone (TSH) Test: Measures TSH levels to assess thyroid function.

Example: Fasting blood sugar and HbA1C tests are commonly used to diagnose and monitor diabetes mellitus.

Complementary Terms

Additional terminology helps describe endocrine system conditions and processes.

• Terms Built from Word Parts:

  • Adenopathy: Disease of a gland (often refers to lymph nodes but can include adrenal glands).

  • Cortical: Pertaining to the cortex (outer layer of an organ).

  • Endocrinology: Study of the endocrine system.

  • Euglycemia: Normal blood glucose level.

  • Polydipsia: Excessive thirst.

  • Syndrome: Group of signs and symptoms occurring together, characteristic of a particular disease.

• Terms Not Built from Word Parts:

  • Exophthalmos: Protruding eyeballs, often associated with Graves disease.

  • Hormone: Chemical substance secreted by an endocrine gland that acts on target tissues.

  • Metabolism: Chemical processes that occur within a living organism to maintain life.

Abbreviations Related to the Endocrine System

Abbreviations are commonly used in medical records and communication.

Abbreviation	Term
ACTH	Adrenocorticotropic hormone
ADH	Antidiuretic hormone
DM	Diabetes mellitus
FBS	Fasting blood sugar
FSH	Follicle-stimulating hormone
GH	Growth hormone
HbA1C	Glycosylated hemoglobin
LH	Luteinizing hormone
PRL	Prolactin hormone
RAIU	Radioactive iodine uptake

Additional info:

• The endocrine system works closely with the nervous system to maintain homeostasis.

• Disorders of the endocrine system can have widespread effects due to the systemic action of hormones.