Module 6 Thyroid Disease; Nutrition; Obesity

NUR1460; T2 A7 Summer Module 6

Thyroid Gland Anatomy

Butterfly-shaped gland

• Located:

  • Anterior to trachea

  • Inferior to larynx

• Contains:

  • Right lobe

  • Left lobe

  • Isthmus

-each of the thyroid lobes are embedded with parathyroid gland (posterior)

-the thyroid follicles are made up of a central cavity filled with a sticky fluid called colloid surrounded by a wall of epithelial follicle cells

T3 (Triiodothyronine) & T4 (Thyroxine)

• Regulate metabolism

• Increase oxygen use

• Produce ATP

• Increase heat production

• Support growth & neurologic function

Remember:

• T3 = more active form

• T4 converts → T3

Excess T3 and T4 hormones

This effect accelerates the heart rate, strengthens the heart contractility, and increases blood pressure

Hormone Regulation/Pathway

-Hypothalamus > TRH

-Pituitary > TSH

-Thyroid > T3 + T4

-Negative Feedback

• High T3/T4 → ↓ TSH o

• Low T3/T4 → ↑ TSH

Functions of Thyroid Hormones in Adult

-Control metabolic rate of all cells

-Promote sufficient pituitary secretion of growth hormone and gonadotropins

-Regulates protein, carbohydrate, and fat metabolism

-Exert effects on heart rate and contractility

-Increase red blood cell production

-Affect respiratory rate and drive

-Increase bone formation and decrease bone resorption of calcium

-Act as insulin antagonists