Week 10: Chp 40: Thyroid Gland

Question 1

Where is the Thyroid Gland Located

Answer 1

in the anterior neck, lying directly below the cricoid cartilage

Question 2

What is the Thyroid Gland composed of?

Answer 2

composed of 2 lobes, the left and the right, it is connected by a strip of tissue called the isthmus

Question 3

The Thyroid Gland Produces what Hormones?

Answer 3

• Triiodothyronine (T3)
• Thyroxine (T4)
• Thyrocalcitonin (calcitonin)

Question 4

What does the Thyroid Gland Regulate?

Answer 4

metabolism

Question 5

Production of The Thyroid Glands requires adequate dietary intake of what?

Answer 5

protein and iodine

Question 6

Release of T3 and T4 is controlled by what?

Answer 6

the hypothalamic-pituitary system and is based on circulating levels of these thyroid hormones

Question 7

What happens when T3 and T4 are low?

Answer 7

the hypothalamus secretes TRH that stimulates the release of TSH from the anterior pituitary gland
-in turn, TSH acts on the thyroid gland, leading to secretion of T3 and T4; while circulating levels of T3 ad T4 increase, the feedback system causes the hypothalamus to decrease release of TRH

Question 8

Other conditions that increase secretion of TRH, independent of circulating T3 and T4, are?

Answer 8

cold and stress

Question 9

Important Assessment Findings of The Thyroid Gland are?

Answer 9

• Mass
• Enlarged Gland
• Goiter
• Asymmetrical Enlargement
• Presence of a Nodule or Bruit (increased blood flow)

Question 10

Normal Assessment Findings for the Thyroid Gland

Answer 10

-Symmetrical movement swallowing
-Adam’s apple more pronounced in males
-No masses, tenderness, or enlargement
-absent or no bruit
>palpate for size, symmetry, shape, and presence of nodule

Question 11

Why is it important to assess plasma protein levels (albumin) when assessing thyroid function?

Answer 11

most circulating T3 and T4 are plasma protein bound

-an increase in free thyroid hormone may occur in the patient with hypoalbuminemia

Question 12

How to Palpate the Thyroid Gland

Answer 12

best palpated by standing behind the patient

• the thumbs of both hands are placed on the back of the neck, and the fingers are curved to the front of the neck on either side of the trachea
• the patient is asked to swallow, and the nurse locates the isthmus by feeling it rise when the patient swallows
• the nurse assesses both the right and left lobes of the thyroid gland; the right lobe is palpated while the patient’s head is turned to the right, and the nurse assesses for any irregularities or nodules; the left is similarly evaluated by having the patient turn the head to the left

Question 13

Diagnostic Testing For Thyroid Disorders

Answer 13

• Thyroid Ultrasound
• CT
• MRI

Question 14

Thyroid Gland Function Tests

Answer 14

• Free T3 (triiodothyronine): 2.6-4.8 pg/mL
• Total T3 (triiodothyronine): 70-204 ng/dL
• Free T4 (thyroxine): 0.8-1.5 ng/dL
• Total T4 (thyroxine): 4.6-12 mcg/dL
• Thyroid-Stimulating Hormone (TSH): 0.5-8.9 microinternational units (mIU)/mL

Question 15

Free T3 (Triiodothyronine)

Answer 15

2. 6-4.8 pg/mL
   - decreased in hypothyroidism
   - increased in hyperthyroidism

Question 16

Total T3 (triiodothyronine)

Answer 16

70-204 ng/dL

• decreased in hypothyroidism
• increased in hyperthyroidism

Question 17

Free T4 (Thyroxine)

Answer 17

0. 8-1.5 ng/dL
   - decreased in hypothyroidism
   - increased in hyperthyroidism

Question 18

Total T4 (Thyroxine)

Answer 18

4. 6-12 mcg/dL
   - decreased in hypothyroidism
   - increased in hyperthyroidism

Question 19

Thyroid-Stimulating Hormone (TSH)

Answer 19

0. 5-8.9 microinternational units (mIU)/mL
   - increased in primary hypothyroidism
   - decreased in secondary or tertiary hypothyroidism
   - decreased in primary hyperthyroidism
   - increased in secondary and tertiary hyperthyroidism

Question 20

Specific Actions of T3 and T4

Answer 20

Secretion of both hormones increases metabolism
-increased rate and contractility of the heart
-increased rate and depth of respirations
-increased oxygen use
-increased glucose intake by cells
-increased glycolysis and enhanced gluconeogenesis
-increased protein synthesis and catabolism
-increased mobilization of fatty acids
-increased oxidation of free fatty acids
-decreased cholesterol and phospholipids
>overall increase in metabolic activity results in increased heat production in all tissues

Question 21

What does Thyrocalcitonin (calcitonin) Do?

Answer 21

decreases serum calcium levels (tones it down)

• calcitonin decreases osteoclastic activity (breakdown/ dissolve of bone)
• stimulates Ca deposition in bones
• reduces Ca+ uptake in kidneys

Question 22

Bone Deposition

Answer 22

a crystallization process in which calcium, phosphate, and other ions are taken from the blood plasma and deposited in bone tissue

Question 23

Bone resorption

Answer 23

process of dissolving bone