Deck 42: The Thyroid Gland

Question 1

A 50-year-old woman complains that in the past few months she has had little energy,has frequently felt chilled,and has noticed excessive hair loss when she washes her hair.During the physical examination,her blood pressure registers at 105/85 mm Hg,her pulse is slow,and her physician notes dry,cool skin with puffiness of the face and arms.A preliminary diagnosis of primary hypothyroidism is made.If the diagnosis is correct,which of the following blood values would be expected?

Answer 1

D

Question 2

Graves' disease is due to an autoantibody that binds to and activates the TSH receptor.This interaction would primarily increase which second messenger in the thyroid epithelial cells?

A)Ca⁺⁺
B)Activated signal transducer and activator of transcription (STAT)
C)Phosphatidylinositol 3-kinase (PI3K)
D)Cyclic guanosine monophosphate (cGMP)
E)Cyclic adenosine monophosphate (cAMP)

Answer 2

E

Question 3

Peripheral deiodinases can have which effect on T₄?

A)Activation
B)Deactivation
C)No effect; theyuse only T₃ as substrate
D)Activation and deactivation

Answer 3

D

Question 4

Secondary hyperthyroidism due to a pituitary tumor would be associated with the following histophysiological characteristics of the thyroid gland (in relation to normal):

A)Increased iodine uptake at 24 hours
B)Increased colloid
C)Tall columnar thyroid epithelium
D)Decreased thyroglobulin endocytosis
E)Lowered organification of iodide

Question 5

A 50-year-old woman complains that in the past few months she has had little energy,has frequently felt chilled,and has noticed excessive hair loss when she washes her hair.During the physical examination,her blood pressure registers at 105/85 mm Hg,her pulse is slow,and her physician notes dry,cool skin with puffiness of the face and arms.A preliminary diagnosis of primary hypothyroidism is made.The primary reason for the elevated diastolic pressure is:

A)Pulmonary congestion.
B)Increased peripheral resistance.
C)Decreased cardiac output.
D)Low catecholamine levels.
E)Increased blood volume.

Question 6

Although pregnant women do not typically exhibit hyperthyroidism,maternal total T₄ levels increase during pregnancy.This benign increase in total T₄ is due to:

A)Increased synthesis of thyroid hormone-binding globulin (TBG).
B)Increased pituitary deiodinase activity.
C)Decreased placental deiodinase activity.
D)Resistance to thyroid hormone receptor signaling.
E)Decreased excretion of thyroid hormone by the kidneys.

Question 7

Which of the following proteins is found only at the basolateral side of thyroid epithelium?

A)Na⁺-I^- symporter
B)Pendrin
C)Megalin
D)Iodotyrosine deiodinase
E)Thyroid peroxidase

Question 8

A primary way by which T₃ increases oxygen consumption and causes heat to be generated (metabolic thermogenesis)in most cells in the body is through increasing the levels of:

A)Myosin heavy chain $\alpha$
B)Glucose transporter 4 (GLUT-4).
C)Uncoupling proteins.
D)Nicotinamide adenine dinucleotide phosphate (NADP)oxidase.
E)Epithelial sodium channel (ENaC).

Question 9

The thyroid hormone receptor is most like which of the following?

A)Adrenergic receptor
B)Insulin receptor
C)Growth hormone receptor
D)Estrogen receptor
E)Follicle-stimulating hormone (FSH)receptor

Question 10

Organification defect specifically concerns the inability of the thyroid to covalently bind iodide to tyrosine residues in the colloid.This reaction is performed by:

A)Thyroid peroxidase.
B)The sodium-iodide transporter.
C)The TSH receptor.
D)Iodotyrosine deiodinases.
E)Thyroglobulin.