The two major hormones secreted by the thyroid gland are:
A. Thyroxine and triiodothyronine
B. Cortisol and aldosterone
C. Insulin and glucagon
D. Calcitonin and PTH

A. Thyroxine and triiodothyronine

Complete lack of thyroid secretion usually causes basal metabolic rate to fall:
A. 10–20% below normal
B. 60–70% below normal
C. 40–50% below normal
D. 5–10% below normal

C. 40–50% below normal

Thyroid secretion is controlled primarily by:
A. ACTH from anterior pituitary
B. TSH from anterior pituitary
C. TSH from posterior pituitary
D. TRH from thyroid gland

B. TSH from anterior pituitary

In addition to T3 and T4, the thyroid gland also secretes:
A. Somatostatin
B. Aldosterone
C. Erythropoietin
D. Calcitonin

D. Calcitonin

Of the metabolically active hormones secreted by the thyroid gland, about 93% is:
A. Thyroxine
B. Triiodothyronine
C. Calcitonin
D. Thyroglobulin

A. Thyroxine

Triiodothyronine (T3) is approximately how much more potent than thyroxine (T4)?
A. Ten times more potent
B. Two times more potent
C. Four times more potent
D. Half as potent

C. Four times more potent

The thyroid gland is composed of large numbers of closed structures called:
A. Acini
B. Follicles
C. Islets
D. Lobules

B. Follicles

The major constituent of thyroid colloid is:
A. Albumin
B. Transthyretin
C. Thyroperoxidase
D. Thyroglobulin

D. Thyroglobulin

Biopsy highlights parafollicular “C cells.” Their key secretion is:
A. Thyroxine
B. Triiodothyronine
C. Calcitonin
D. Thyroglobulin

C. Calcitonin

After oral ingestion, iodides are primarily:
A. Secreted into bile
B. Converted to iodate
C. Excreted in stool
D. Absorbed into blood

D. Absorbed into blood

The first stage in thyroid hormone formation is:
A. Iodination of thyroglobulin
B. Transport iodide into thyroid
C. Proteolysis of thyroglobulin
D. Deiodination of T4

B. Transport iodide into thyroid

The sodium-iodide symporter transports:
A. One sodium with one iodide
B. Two iodide with one sodium
C. Two sodium with one iodide
D. One chloride with one iodide

C. Two sodium with one iodide

The process of concentrating iodide inside thyroid cells is called:
A. Iodide trapping
B. Iodide organification
C. Iodide coupling
D. Iodide recycling

A. Iodide trapping

Iodide is transported across the apical membrane into the follicle by:
A. Basolateral iodide efflux pump
B. Apical sodium-iodide symporter
C. Apical iodide-protein transporter
D. Apical chloride-iodide exchanger

D. Apical chloride-iodide exchanger

The thyroid’s hormone-secreting epithelial cells are best described as:
A. Typical protein-secreting gland cells
B. Typical steroid-secreting gland cells
C. Typical neurotransmitter-secreting cells
D. Typical exocrine ductal cells

A. Typical protein-secreting gland cells

Each molecule of thyroglobulin contains about:
A. About 10 tyrosines
B. About 70 tyrosines
C. About 700 tyrosines
D. About 25 tyrosines

B. About 70 tyrosines

The first essential chemical step enabling hormone formation is to:
A. Oxidize iodide for tyrosine binding
B. Store T3 in vesicles
C. Convert T4 into T3
D. Export T4 via pendrin

A. Oxidize iodide for tyrosine binding

Oxidation of iodine is promoted by:
A. Deiodinase with NADPH
B. Thyroglobulin with iodine
C. Peroxidase with hydrogen peroxide
D. Pendrin with chloride gradient

C. Peroxidase with hydrogen peroxide

Thyroid follicles are lined primarily by:
A. Squamous epithelial cells
B. Cuboidal epithelial cells
C. Columnar epithelial cells
D. Transitional epithelial cells

B. Cuboidal epithelial cells

Thyroglobulin contains about 70 of which amino acid residues?
A. Lysine residues
B. Cysteine residues
C. Tryptophan residues
D. Tyrosine residues

D. Tyrosine residues

Iodide exits thyroid cells into the follicle lumen via:
A. Sodium-iodide symporter
B. Pendrin
C. Peroxidase
D. Thyroglobulin

B. Pendrin

A newborn has a hereditary absence of the thyroid peroxidase system. Thyroid hormone synthesis rate falls to:
A. Decreases modestly
B. Falls to one-third
C. Falls to half
D. Falls to zero

D. Falls to zero

The binding of iodine to the thyroglobulin molecule is termed:
A. Organification of thyroglobulin
B. Iodide trapping
C. Coupling reaction
D. Deiodination

A. Organification of thyroglobulin

During iodination, tyrosine is converted first to:
A. DIT then MIT
B. T4 then T3
C. MIT then DIT
D. T3 then T4

C. MIT then DIT

Two molecules of diiodotyrosine couple to form:
A. Thyroxine (T4)
B. Triiodothyronine (T3)
C. Reverse T3
D. Thyroglobulin

A. Thyroxine (T4)

One MIT plus one DIT couples to form:
A. Thyroxine (T4)
B. Reverse T3
C. Diiodotyrosine
D. Triiodothyronine (T3)

D. Triiodothyronine (T3)

The thyroid gland is unusual among endocrine glands because it:
A. Has minimal storage capacity
B. Stores large hormone amounts
C. Stores only calcitonin
D. Stores only iodide

B. Stores large hormone amounts

Most thyroglobulin is ______ into circulating blood:
A. Rapidly released
B. Slowly released
C. Not released
D. Pulsatile release

C. Not released

During hormone release, apical pseudopods primarily form:
A. Pinocytic vesicles
B. Secretory granules
C. Tight-junction pores
D. Ribosomal channels

A. Pinocytic vesicles

Lysosomes fuse with pinocytic vesicles to form:
A. Storage vesicles
B. Peroxisomes
C. Digestive vesicles
D. Golgi cisternae

C. Digestive vesicles

The key enzymes freeing T3/T4 from thyroglobulin are:
A. Lipases
B. Kinases
C. Polymerases
D. Proteases

D. Proteases

Some colloid thyroglobulin enters thyroid cells via:
A. Diffusion through colloid
B. Megalin-mediated endocytosis
C. Pendrin cotransport
D. NIS symport

B. Megalin-mediated endocytosis

About what fraction of iodinated tyrosines remain MIT/DIT, never becoming thyroid hormones?
A. One tenth
B. One third
C. Three quarters
D. All of them

C. Three quarters

Deiodinase enzymes primarily:
A. Couple MIT with DIT
B. Trap iodide in cell
C. Oxidize iodide
D. Recycle iodine within gland

D. Recycle iodine within gland

Lack of deiodinase enzymes can cause:
A. Iodine deficiency
B. Hypercalcemia
C. Iron deficiency
D. Zinc deficiency

A. Iodine deficiency

On entering blood, T3/T4 bind immediately to:
A. RBC hemoglobin
B. Plasma proteins
C. Platelets
D. Immunoglobulins

B. Plasma proteins

The major thyroid hormone–binding proteins are:
A. CBG, transferrin, albumin
B. SHBG, albumin, haptoglobin
C. TBG, albumin, haptoglobin
D. TBG, transthyretin, albumin

D. TBG, transthyretin, albumin

After a large thyroxine injection, metabolic effects are minimal for:
A. Two to three days
B. Two to three hours
C. Ten to twelve days
D. Immediate effect

A. Two to three days

Thyroxine reaches maximal effect at about:
A. 24 hours
B. Ten to twelve days
C. Three to four days
D. Several months

B. Ten to twelve days

The general effect of thyroid hormone is to:
A. Block ribosomal translation
B. Open calcium channels
C. Activate nuclear gene transcription
D. Inhibit cAMP formation

C. Activate nuclear gene transcription

Most thyroxine secreted is converted to:
A. Reverse T3
B. Triiodothyronine (T3)
C. Calcitonin
D. Thyroglobulin

B. Triiodothyronine (T3)

About 90% of receptor-bound thyroid hormone is:
A. Thyroxine
B. Reverse T3
C. Diiodotyrosine
D. Triiodothyronine

D. Triiodothyronine

Thyroid hormone receptor usually heterodimerizes with:
A. Retinoid X receptor
B. Vitamin D receptor
C. Estrogen receptor
D. Glucocorticoid receptor

A. Retinoid X receptor

TR/RXR binds DNA at:
A. CpG islands
B. TATA boxes
C. Thyroid response elements
D. Splice donor sites

C. Thyroid response elements

A researcher infuses TSH into isolated thyroid follicles. Which immediate change most directly increases hormone release?
A. Increased thyroglobulin exocytosis
B. Decreased lysosomal enzyme activity
C. Increased proteolysis of thyroglobulin
D. Decreased colloid endocytosis

C. Increased proteolysis of thyroglobulin

Patient with low thyroid hormone has elevated TSH. Which transport step is most upregulated in thyroid cells?
A. Increased iodide pump activity
B. Decreased apical iodide efflux
C. Reduced thyroid peroxidase activity
D. Increased hepatic T4 clearance

A. Increased iodide pump activity

In a euthyroid patient given exogenous TSH, which synthetic step increases within the follicle?
A. Decreased MIT formation
B. Decreased DIT formation
C. Reduced coupling reactions
D. Increased tyrosine iodination

D. Increased tyrosine iodination

Chronic TSH excess most strongly causes which cellular adaptation?
A. Reduced follicular cell secretion
B. Increased cell size and secretion
C. Decreased iodide trapping
D. Follicular cell apoptosis

B. Increased cell size and secretion

Long-standing TSH stimulation most likely produces which histologic change?
A. Cuboidal to columnar shift
B. Flattened epithelium, scant colloid
C. Loss of follicular architecture
D. C-cell hyperplasia predominates

A. Cuboidal to columnar shift

Anterior pituitary TSH secretion is primarily controlled by which hypothalamic hormone?
A. Somatostatin
B. Dopamine
C. Thyrotropin-releasing hormone
D. Corticotropin-releasing hormone

C. Thyrotropin-releasing hormone

TRH is best described chemically as:
A. Glycyl-lysyl-arginine-amide
B. Histidyl-prolyl-glycine-amide
C. Leucyl-tyrosyl-alanine-amide
D. Pyroglutamyl-histidylproline-amide

D. Pyroglutamyl-histidylproline-amide

TSH receptor activation primarily signals through:
A. IP3/DAG pathway
B. cAMP second messenger
C. JAK/STAT signaling
D. Tyrosine kinase signaling

B. cAMP second messenger

TRH receptor activation primarily uses:
A. cGMP second messenger
B. cAMP second messenger
C. Phospholipase C pathway
D. Nuclear receptor binding

C. Phospholipase C pathway

A child exposed to cold has increased thyroid drive. Best-known trigger upstream of TSH is:
A. Increased cortisol secretion
B. Increased dopamine secretion
C. Increased somatostatin release
D. Increased TRH secretion

D. Increased TRH secretion

Which set lists the best-known antithyroid drugs?
A. Methimazole, levothyroxine, iodine
B. Propranolol, lithium, amiodarone
C. Thiocyanate, PTU, iodides
D. T3, T4, calcitonin

C. Thiocyanate, PTU, iodides

Thiocyanate ions primarily decrease which thyroid process?
A. Coupling of iodotyrosines
B. Iodide trapping
C. Proteolysis of thyroglobulin
D. Peripheral T4 to T3 conversion

B. Iodide trapping

Chronic blockade of thyroid secretion by thiocyanate can lead to:
A. Myxedema coma
B. Thyroid storm
C. Exophthalmos
D. Goiter

D. Goiter

Which drug prevents thyroid hormone formation from iodides and tyrosine?
A. Propylthiouracil
B. Levothyroxine
C. Calcitonin
D. Liothyronine

A. Propylthiouracil

Iodides in very high concentration most consistently:
A. Increase iodide trapping
B. Increase TSH secretion
C. Decrease all thyroid activity phases
D. Increase coupling reactions

C. Decrease all thyroid activity phases

A patient is scheduled for thyroidectomy in 3 weeks. Why give iodide 2–3 weeks pre-op?
A. Induce autoimmune remission
B. Decrease necessary surgery amount
C. Increase T3 potency at receptors
D. Stimulate follicular hyperplasia

B. Decrease necessary surgery amount

The most common form of hyperthyroidism is:
A. Toxic multinodular goiter
B. Subacute thyroiditis
C. Thyroid adenoma
D. Graves’ disease

D. Graves’ disease

Graves’ disease is best explained by:
A. TSIs activate TSH receptor cAMP
B. Anti-thyroglobulin blocks hormone release
C. Anti-peroxidase increases iodide oxidation
D. TSH receptor mutations reduce signaling

A. TSIs activate TSH receptor cAMP

Hyperthyroidism arising within thyroid tissue that secretes large hormone quantities is:
A. Thyroid adenoma
B. Hashimoto disease
C. Endemic goiter
D. Subacute thyroiditis

A. Thyroid adenoma

A patient with excess thyroid hormone most likely reports:
A. Cold intolerance
B. High excitability
C. Bradykinesia
D. Hypersomnia

B. High excitability

A patient with thyrotoxicosis most characteristically develops:
A. Heat intolerance
B. Heat-seeking behavior
C. Decreased skin perfusion
D. Reduced sweat production

A. Heat intolerance

A hyperthyroid patient develops frequent loose stools. This symptom is best described as:
A. Constipation predominant
B. Steatorrhea predominant
C. Hematochezia predominant
D. Varying degrees of diarrhea

D. Varying degrees of diarrhea

Which finding best reflects hyperthyroid skeletal muscle effects?
A. Hyperreflexia
B. Muscle weakness
C. Increased muscle bulk
D. Spastic rigidity

B. Muscle weakness

A patient is “exhausted but can’t sleep.” This pattern best fits:
A. Hypothyroid hypersomnia
B. Major depression hypersomnia
C. Fatigue with insomnia
D. Obstructive sleep apnea

C. Fatigue with insomnia

A hyperthyroid patient’s hands shake when holding a cup. This is:
A. Tremor of hands
B. Asterixis of hands
C. Clonus of wrists
D. Chorea of fingers

A. Tremor of hands

“Protrusion of eyeballs” in hyperthyroidism is called:
A. Ptosis
B. Enophthalmos
C. Nystagmus
D. Exophthalmos

D. Exophthalmos

Exophthalmos accompanied by circulating immunoglobulins suggests:
A. Toxic adenoma mechanism
B. Autoimmune process
C. Iodine deficiency mechanism
D. Drug-induced thyroiditis

B. Autoimmune process

The most accurate diagnostic test for hyperthyroidism listed here is:
A. Basal metabolic rate
B. Serum TSH by RIA
C. Free thyroxine level
D. Serum TSI by RIA

C. Free thyroxine level

Which test is specifically noted as measured by radioimmunoassay?
A. Serum TSH concentration
B. Basal metabolic rate
C. Stool fat quantification
D. Reflex tendon latency

A. Serum TSH concentration

In suspected Graves disease, which antibody assay is noted as measured by radioimmunoassay?
A. Anti-centromere
B. Anti-dsDNA
C. Anti-mitochondrial
D. Thyroid-stimulating immunoglobulin

D. Thyroid-stimulating immunoglobulin

The most direct treatment for hyperthyroidism is:
A. Propylthiouracil therapy
B. Surgical thyroid removal
C. Cold exposure avoidance
D. Dietary iodine supplementation

B. Surgical thyroid removal

A hyperplastic thyroid is treated most directly with:
A. Oral calcium carbonate
B. Levothyroxine replacement
C. Radioactive iodide therapy
D. Dopamine agonist therapy

C. Radioactive iodide therapy

The autoimmune cause of hypothyroidism is:
A. Hashimoto’s disease
B. Graves’ disease
C. Thyroid adenoma
D. Endemic goiter

A. Hashimoto’s disease

Progressive deterioration and fibrosis of the thyroid gland is most consistent with:
A. Adenoma degeneration
B. Thyroid hormone resistance
C. Iodide excess toxicity
D. Thyroiditis

D. Thyroiditis

In regions with insufficient iodine intake, people commonly develop:
A. Graves disease
B. Thyroid adenoma
C. Endemic goiters
D. Hashimoto disease

C. Endemic goiters

A colloid goiter can result from which abnormality?
A. Deficient iodide-trapping mechanism
B. Excess calcitonin secretion
C. Excess TRH secretion
D. Increased T3 receptor affinity

A. Deficient iodide-trapping mechanism

A colloid goiter can result from which abnormality?
A. Excess iodide organification
B. Deficient peroxidase system
C. Excess coupling of iodotyrosines
D. Increased deiodinase recycling

B. Deficient peroxidase system

A colloid goiter can result from which abnormality?
A. Increased iodide trapping
B. Increased thyroglobulin proteolysis
C. Increased TSH receptor cAMP
D. Deficient coupling of iodotyrosines

D. Deficient coupling of iodotyrosines

A colloid goiter can result from which abnormality?
A. Excess pendrin transport
B. Excess thyroid peroxidase
C. Deiodinase enzyme deficiency
D. Excess plasma protein binding

C. Deiodinase enzyme deficiency

Some foods contain substances with PTU-like activity causing TSH-stimulated thyroid enlargement. These are:
A. Thyroid-stimulating immunoglobulins
B. Goitrogenic substances
C. Thyroxine-binding globulins
D. Inorganic iodides

B. Goitrogenic substances

An adult has near-total thyroid hormone loss with swelling and a baggy face. This condition is:
A. Graves disease
B. Myxedema
C. Thyroid adenoma
D. Subacute thyroiditis

B. Myxedema

The edema in myxedema is best explained by excess interstitial:
A. Albumin leakage
B. Sodium chloride crystals
C. Lipid droplets
D. Hyaluronic–chondroitin protein gel

D. Hyaluronic–chondroitin protein gel

Which hypothyroid test pattern best matches classic teaching?
A. Low free T4, high TSH
B. High free T4, low TSH
C. Low TSH, high BMR
D. High TSH, high BMR

A. Low free T4, high TSH

Proper long-term treatment for primary hypothyroidism is:
A. Calcitonin replacement
B. TRH supplementation
C. Thyroxine administration
D. Propylthiouracil therapy

C. Thyroxine administration

Extreme hypothyroidism during childhood causing poor growth and mental retardation is:
A. Myxedema
B. Graves disease
C. Thyroid storm
D. Cretinism

D. Cretinism

The two major categories of cretinism are:
A. Autoimmune and iatrogenic
B. Congenital and endemic
C. Toxic and nontoxic
D. Central and peripheral

B. Congenital and endemic

A neonate with cretinism must receive which therapy early to prevent deficits?
A. Iodine or thyroxine early
B. Radioiodine ablation early
C. Propylthiouracil early
D. Surgery within first weeks

A. Iodine or thyroxine early

In cretinism, which growth pattern best explains “short, stocky, obese” appearance?
A. Soft tissue more inhibited
B. Both equally inhibited
C. Skeletal more inhibited
D. Skeletal unaffected, soft tissue

C. Skeletal more inhibited

Which pairing best matches thyroid outputs and functions?
A. T3 lowers calcium, T4 raises calcium
B. Calcitonin raises calcium, T4 lowers calcium
C. T3 lowers calcium, calcitonin raises rate
D. T3/T4 raise rate, calcitonin lowers calcium

D. T3/T4 raise rate, calcitonin lowers calcium

Sodium-iodide symporter is located on the:
A. Basolateral plasma membrane
B. Apical follicular membrane
C. Nuclear membrane
D. Mitochondrial inner membrane

A. Basolateral plasma membrane

Energy driving iodide uptake via NIS comes from:
A. Direct ATP hydrolysis by NIS
B. Chloride gradient across apical side
C. Na-K ATPase sodium gradient
D. Iodine oxidation releasing energy

C. Na-K ATPase sodium gradient

As thyroid activity increases, intracellular iodide becomes:
A. Lower than blood
B. Similar to blood
C. Slightly below blood
D. Higher than blood

D. Higher than blood

Which hormone increases NIS activity?
A. Calcitonin
B. Thyroid-stimulating hormone
C. Somatostatin
D. Prolactin

B. Thyroid-stimulating hormone

Thyroid epithelial cells secrete into follicle a protein providing tyrosines for iodination:
A. Albumin
B. Calcitonin
C. Thyroglobulin
D. Thyroxine-binding prealbumin

C. Thyroglobulin

Two organelles key for thyroglobulin synthesis/secretion are:
A. Smooth ER and lysosome
B. Rough ER and Golgi
C. Nucleus and mitochondria
D. Ribosome and peroxisome

B. Rough ER and Golgi

In presence of hydrogen peroxide, which enzyme converts iodide to iodine?
A. Deiodinase
B. Pendrin
C. Megalin
D. Peroxidase

D. Peroxidase

After coupling, which hormone remains part of the thyroglobulin molecule?
A. Thyroxine (T4)
B. Triiodothyronine (T3)
C. Calcitonin
D. Reverse T3

A. Thyroxine (T4)

The storage form of thyroid hormone not released into blood is:
A. Free T3
B. Free T4
C. Thyroglobulin
D. Thyroxine-binding globulin

C. Thyroglobulin

Release of T3/T4 from thyroglobulin begins with:
A. Exocytosis of secretory granules
B. Pinocytosis of colloid
C. Diffusion across apical membrane
D. Transcriptional activation

B. Pinocytosis of colloid

The enzymatic step liberating free T3/T4 uses:
A. Phosphatases
B. Ligases
C. Deiodinases
D. Lysosomal proteases

D. Lysosomal proteases

Luminal membrane protein mediating thyroglobulin endocytosis/transcytosis is:
A. Megalin
B. Pendrin
C. NIS
D. TBG

A. Megalin

The specific glycosaminoglycans increased in myxedema include:
A. Keratan sulfate and dermatan sulfate
B. Heparin and heparan sulfate
C. Hyaluronidase and collagenase
D. Hyaluronic acid and chondroitin sulfate

D. Hyaluronic acid and chondroitin sulfate

In primary hypothyroidism, which lab change is expected?
A. Decreased TSH secretion
B. Increased TSH secretion
C. Increased free T4
D. Increased basal metabolic rate

B. Increased TSH secretion

The “baggy face” of severe hypothyroidism is most directly due to:
A. Acute capillary hemorrhage
B. Lipid deposition in dermis
C. Interstitial glycosaminoglycan gel
D. Excess adrenergic vasodilation

C. Interstitial glycosaminoglycan gel

Which thyroid hormone binds plasma proteins most avidly?
A. T3
B. Calcitonin
C. T4
D. Thyroglobulin

C. T4

Higher plasma-binding affinity best matches which release pattern?
A. T4 1 day; T3 6 days
B. T4 3 days; T3 3 days
C. T4 1 day; T3 1 day
D. T4 6 days; T3 1 day

D. T4 6 days; T3 1 day

A thyroid preparation is slower acting with longer latent period and longer half-life. Which hormone is it?
A. T4
B. T3
C. Calcitonin
D. Thyroglobulin

A. T4

Thyroid hormone increases functional activity throughout the body primarily by:
A. Opening ligand-gated channels
B. Activating membrane GPCRs
C. Increasing gene transcription
D. Inhibiting DNA replication

C. Increasing gene transcription

The thyroid hormone that directly binds intracellular thyroid receptors to drive transcription is:
A. T4
B. T3
C. Calcitonin
D. Thyroglobulin

B. T3

Over 90% of thyroid hormone bound to receptors is:
A. T3
B. T4
C. MIT
D. DIT

A. T3

The TR/RXR complex initiates transcription by binding:
A. TATA boxes
B. TREs
C. EREs
D. GREs

B. TREs

Increased “leakiness” of which ion most raises heat production and BMR?
A. Na+
B. K+
C. Cl−
D. Ca2+

A. Na+

A child becomes tall early; bones mature rapidly; epiphyses close early; adult height may be reduced. Most consistent thyroid state:
A. Hypothyroidism
B. Euthyroid
C. Thyroid hormone resistance
D. Hyperthyroidism

D. Hyperthyroidism

Thyroid hormone effect on carbohydrate and fat metabolism is:
A. Decreases both pathways
B. Increases CHO only
C. Increases both pathways
D. Increases fat only

C. Increases both pathways

In hypothyroidism, expected lipid pattern is:
A. ↑chol, ↑PL, ↑TG; ↓FFA
B. ↓chol, ↓PL, ↓TG; ↑FFA
C. ↑FFA, ↓chol, ↓TG
D. ↓PL, ↓chol; ↑FFA

A. ↑chol, ↑PL, ↑TG; ↓FFA

Thyroid hormone lowers cholesterol partly by:
A. Decreasing bile cholesterol secretion
B. ↑bile secretion, ↑fecal loss
C. Increasing intestinal cholesterol absorption
D. Blocking hepatic bile formation

B. ↑bile secretion, ↑fecal loss

Thyroid hormone lowers LDL largely by increasing hepatic:
A. Lipoprotein lipase activity
B. VLDL secretion rate
C. ApoA-I synthesis
D. LDL receptor expression

D. LDL receptor expression

Normal thyroid hormone effect on free fatty acids is:
A. Increases free fatty acids
B. Decreases free fatty acids
C. No change in free acids
D. Eliminates plasma free acids

A. Increases free fatty acids

Excess thyroid hormone raises vitamin requirements mainly because it:
A. Suppresses enzyme production
B. Decreases transcriptional activity
C. Increases enzyme production
D. Blocks vitamin hepatic storage

C. Increases enzyme production

Which hyperthyroid pattern is most expected?
A. ↓BMR, ↓weight
B. ↑BMR, ↓weight
C. ↓BMR, ↑weight
D. ↑BMR, ↑weight

B. ↑BMR, ↓weight

In hyperthyroidism, blood flow and cardiac output typically:
A. Decrease both
B. Increase flow, decrease output
C. Decrease flow, increase output
D. Increase both

D. Increase both

In hyperthyroidism, heart rate and contractile strength:
A. Increase both
B. Decrease both
C. Increase rate, decrease strength
D. Decrease rate, increase strength

A. Increase both

Thyroid hormone has little net effect on mean arterial pressure because:
A. Both systolic and diastolic rise
B. Both systolic and diastolic fall
C. Systolic rises, diastolic falls
D. Diastolic rises, systolic falls

C. Systolic rises, diastolic falls

Which combination best maintains mean arterial pressure with thyroid hormone?
A. ↓systolic, ↑diastolic; ↓pulse pressure
B. ↑systolic, ↑diastolic; ↓pulse pressure
C. ↓systolic, ↓diastolic; ↑pulse pressure
D. ↑systolic, ↓diastolic; ↑pulse pressure

D. ↑systolic, ↓diastolic; ↑pulse pressure

Excess thyroid hormone effect on respiration is:
A. Decreases rate and depth
B. Increases rate and depth
C. Increases depth only
D. Increases rate only

B. Increases rate and depth

Excess thyroid hormone effect on GI motility is:
A. Increased motility
B. Decreased motility
C. No change in motility
D. Complete motility paralysis

A. Increased motility

Hyperthyroidism effect on CNS most resembles:
A. Psychomotor slowing, apathy
B. CNS depression, confusion
C. Flaccid paralysis, coma
D. CNS stimulation, anxiety

D. CNS stimulation, anxiety

Hyperthyroidism effect on muscle mass is:
A. Increased protein synthesis
B. Increased muscle hypertrophy
C. Decreased via catabolism
D. Unchanged muscle protein turnover

C. Decreased via catabolism

A patient with chronic diarrhea is more consistent with:
A. Hypothyroidism
B. Hyperthyroidism
C. Isolated calcitonin excess
D. Addison disease

B. Hyperthyroidism

A patient with constipation is more consistent with:
A. Hyperthyroidism
B. Euthyroid state
C. Graves disease
D. Hypothyroidism

D. Hypothyroidism

Hyperthyroid tremor is best described as:
A. Fine “paper vibration” tremor
B. Coarse “shivering” tremor
C. Intention tremor
D. Resting pill-rolling tremor

A. Fine “paper vibration” tremor

Parkinson tremor is best described as:
A. Fine paper vibration
B. Pure intention tremor
C. Coarse shivering tremor
D. Only postural tremor

C. Coarse shivering tremor

A patient sleeping 12–14 hours daily most suggests:
A. Hypothyroidism
B. Hyperthyroidism
C. Thyroid storm
D. Anxiety disorder

A. Hypothyroidism

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In men, lack vs excess thyroid hormone most classically causes:
A. Lack impotence; excess libido
B. Lack libido gain; excess loss
C. Lack oliguria; excess polyuria
D. Lack libido loss; excess impotence

D. Lack libido loss; excess impotence

In women, thyroid hormone deficiency is associated with:
A. Oligomenorrhea
B. Amenorrhea
C. Menorrhagia, polymenorrhea, irregular
D. No menstrual changes

C. Menorrhagia, polymenorrhea, irregular

In women, excess thyroid hormone is associated with:
A. Menorrhagia and polymenorrhea
B. Oligomenorrhea and amenorrhea
C. Continuous heavy bleeding
D. Regular cycles

B. Oligomenorrhea and amenorrhea

TSH stimulation increases which thyroid process?
A. Iodide pump activity
B. Decreased iodide trapping
C. Reduced iodination rate
D. Reduced follicular transport

A. Iodide pump activity

TSH stimulation increases which release-related step?
A. Reduced lysosomal activity
B. Decreased colloid uptake
C. Increased hormone deiodination
D. Increased thyroglobulin proteolysis

D. Increased thyroglobulin proteolysis

Chronic TSH stimulation increases:
A. Follicular flattening, less secretion
B. Thyroid cell number increases
C. C-cell number increases
D. Follicles disappear completely

B. Thyroid cell number increases

TSH increases hormone synthesis partly by:
A. Increasing tyrosine iodination
B. Blocking iodide oxidation
C. Decreasing coupling reactions
D. Preventing MIT/DIT formation

A. Increasing tyrosine iodination

TSH activates thyroid follicular cells primarily via:
A. JAK-STAT signaling
B. PLC → Ca2+ + DAG
C. cAMP second messenger
D. Tyrosine kinase cascade

C. cAMP second messenger

TRH enters hypophysial portal blood from the:
A. Median eminence
B. Supraoptic nucleus
C. Posterior pituitary
D. Anterior pituitary

A. Median eminence

TRH triggers TSH release using:
A. cGMP signaling
B. PLC → Ca2+ + DAG
C. cAMP signaling
D. Nuclear receptor binding

B. PLC → Ca2+ + DAG

If the hypophysial stalk is cut, cold tolerance is preserved because:
A. TSH is autonomous
B. Thyroid senses cold directly
C. Hypothalamus increases TRH
D. Pituitary stores TRH long-term

C. Hypothalamus increases TRH

Which antithyroid drug decreases iodide trapping?
A. Thiocyanate
B. Propylthiouracil
C. High-dose iodides
D. Radioactive iodide

A. Thiocyanate

Which antithyroid drug blocks peroxidase and coupling?
A. Thiocyanate
B. Propylthiouracil
C. High-dose iodides
D. Levothyroxine

B. Propylthiouracil

Which therapy decreases thyroid activity and size?
A. Thiocyanate
B. Propylthiouracil
C. TRH infusion
D. High-dose iodides

D. High-dose iodides

Autoimmune hyperthyroidism with TSIs against TSH receptors is:
A. Hashimoto disease
B. Graves disease
C. Subacute thyroiditis
D. Colloid goiter

B. Graves disease

A tumor secretes thyroid hormone, suppressing pituitary TSH. This is:
A. Thyroid adenoma
B. Graves disease
C. Hashimoto disease
D. Endemic goiter

A. Thyroid adenoma

Exophthalmos can endanger vision by compressing the:
A. Oculomotor nerve
B. Trochlear nerve
C. Abducens nerve
D. Optic nerve

D. Optic nerve

Exophthalmos in thyrotoxicosis is caused mainly by:
A. Corneal edema
B. Lens swelling
C. Retro-orbital edema + myopathy
D. Increased aqueous humor

C. Retro-orbital edema + myopathy

In classic thyrotoxicosis, plasma TSH is typically:
A. Absent or very low
B. High with normal T4
C. Normal with high TRH
D. High with high T3

A. Absent or very low

Autoimmune destruction causing thyroiditis and goiter is:
A. Graves disease
B. Hashimoto disease
C. Thyroid adenoma
D. Myxedema coma

B. Hashimoto disease

Iodine deficiency causes goiter primarily through:
A. Increased calcitonin secretion
B. Increased T3 potency
C. Low T3/T4 → high TSH
D. High TRH → low TSH

C. Low T3/T4 → high TSH

Goiter in people without iodine deficiency is:
A. Endemic goiter
B. Graves goiter
C. Toxic multinodular goiter
D. Idiopathic nontoxic colloid goiter

D. Idiopathic nontoxic colloid goiter

Which food contains goitrogenic substances?
A. Cabbages or turnips
B. Apples or bananas
C. Beef or chicken
D. Rice or wheat

A. Cabbages or turnips

Froglike husky voice with diffuse edema suggests:
A. Graves disease
B. Myxedema
C. Thyroid adenoma
D. Exophthalmos syndrome

B. Myxedema

Endemic cretinism most commonly results from:
A. TSH receptor mutation
B. TSIs against TSH receptor
C. Dietary iodine deficiency
D. Pituitary TSH-secreting tumor

C. Dietary iodine deficiency