front 1 The two major hormones secreted by the thyroid gland are: | back 1 A. Thyroxine and triiodothyronine |
front 2 Complete lack of thyroid secretion usually causes basal metabolic
rate to fall: | back 2 C. 40–50% below normal |
front 3 Thyroid secretion is controlled primarily by: | back 3 B. TSH from anterior pituitary |
front 4 In addition to T3 and T4, the thyroid gland also secretes: | back 4 D. Calcitonin |
front 5 Of the metabolically active hormones secreted by the thyroid gland,
about 93% is: | back 5 A. Thyroxine |
front 6 Triiodothyronine (T3) is approximately how much more potent than
thyroxine (T4)? | back 6 C. Four times more potent |
front 7 The thyroid gland is composed of large numbers of closed structures
called: | back 7 B. Follicles |
front 8 The major constituent of thyroid colloid is: | back 8 D. Thyroglobulin |
front 9 Biopsy highlights parafollicular “C cells.” Their key secretion
is: | back 9 C. Calcitonin |
front 10 After oral ingestion, iodides are primarily: | back 10 D. Absorbed into blood |
front 11 The first stage in thyroid hormone formation is: | back 11 B. Transport iodide into thyroid |
front 12 The sodium-iodide symporter transports: | back 12 C. Two sodium with one iodide |
front 13 The process of concentrating iodide inside thyroid cells is
called: | back 13 A. Iodide trapping |
front 14 Iodide is transported across the apical membrane into the follicle
by: | back 14 D. Apical chloride-iodide exchanger |
front 15 The thyroid’s hormone-secreting epithelial cells are best described
as: | back 15 A. Typical protein-secreting gland cells |
front 16 Each molecule of thyroglobulin contains about: | back 16 B. About 70 tyrosines |
front 17 The first essential chemical step enabling hormone formation is
to: | back 17 A. Oxidize iodide for tyrosine binding |
front 18 Oxidation of iodine is promoted by: | back 18 C. Peroxidase with hydrogen peroxide |
front 19 Thyroid follicles are lined primarily by: | back 19 B. Cuboidal epithelial cells |
front 20 Thyroglobulin contains about 70 of which amino acid residues? | back 20 D. Tyrosine residues |
front 21 Iodide exits thyroid cells into the follicle lumen via: | back 21 B. Pendrin |
front 22 A newborn has a hereditary absence of the thyroid peroxidase system.
Thyroid hormone synthesis rate falls to: | back 22 D. Falls to zero |
front 23 The binding of iodine to the thyroglobulin molecule is
termed: | back 23 A. Organification of thyroglobulin |
front 24 During iodination, tyrosine is converted first to: | back 24 C. MIT then DIT |
front 25 Two molecules of diiodotyrosine couple to form: | back 25 A. Thyroxine (T4) |
front 26 One MIT plus one DIT couples to form: | back 26 D. Triiodothyronine (T3) |
front 27 The thyroid gland is unusual among endocrine glands because
it: | back 27 B. Stores large hormone amounts |
front 28 Most thyroglobulin is ______ into circulating blood: | back 28 C. Not released |
front 29 During hormone release, apical pseudopods primarily form: | back 29 A. Pinocytic vesicles |
front 30 Lysosomes fuse with pinocytic vesicles to form: | back 30 C. Digestive vesicles |
front 31 The key enzymes freeing T3/T4 from thyroglobulin are: | back 31 D. Proteases |
front 32 Some colloid thyroglobulin enters thyroid cells via: | back 32 B. Megalin-mediated endocytosis |
front 33 About what fraction of iodinated tyrosines remain MIT/DIT, never
becoming thyroid hormones? | back 33 C. Three quarters |
front 34 Deiodinase enzymes primarily: | back 34 D. Recycle iodine within gland |
front 35 Lack of deiodinase enzymes can cause: | back 35 A. Iodine deficiency |
front 36 On entering blood, T3/T4 bind immediately to: | back 36 B. Plasma proteins |
front 37 The major thyroid hormone–binding proteins are: | back 37 D. TBG, transthyretin, albumin |
front 38 After a large thyroxine injection, metabolic effects are minimal
for: | back 38 A. Two to three days |
front 39 Thyroxine reaches maximal effect at about: | back 39 B. Ten to twelve days |
front 40 The general effect of thyroid hormone is to: | back 40 C. Activate nuclear gene transcription |
front 41 Most thyroxine secreted is converted to: | back 41 B. Triiodothyronine (T3) |
front 42 About 90% of receptor-bound thyroid hormone is: | back 42 D. Triiodothyronine |
front 43 Thyroid hormone receptor usually heterodimerizes with: | back 43 A. Retinoid X receptor |
front 44 TR/RXR binds DNA at: | back 44 C. Thyroid response elements |
front 45 A researcher infuses TSH into isolated thyroid follicles. Which
immediate change most directly increases hormone release? | back 45 C. Increased proteolysis of thyroglobulin |
front 46 Patient with low thyroid hormone has elevated TSH. Which transport
step is most upregulated in thyroid cells? | back 46 A. Increased iodide pump activity |
front 47 In a euthyroid patient given exogenous TSH, which synthetic step
increases within the follicle? | back 47 D. Increased tyrosine iodination |
front 48 Chronic TSH excess most strongly causes which cellular
adaptation? | back 48 B. Increased cell size and secretion |
front 49 Long-standing TSH stimulation most likely produces which histologic
change? | back 49 A. Cuboidal to columnar shift |
front 50 Anterior pituitary TSH secretion is primarily controlled by which
hypothalamic hormone? | back 50 C. Thyrotropin-releasing hormone |
front 51 TRH is best described chemically as: | back 51 D. Pyroglutamyl-histidylproline-amide |
front 52 TSH receptor activation primarily signals through: | back 52 B. cAMP second messenger |
front 53 TRH receptor activation primarily uses: | back 53 C. Phospholipase C pathway |
front 54 A child exposed to cold has increased thyroid drive. Best-known
trigger upstream of TSH is: | back 54 D. Increased TRH secretion |
front 55 Which set lists the best-known antithyroid drugs? | back 55 C. Thiocyanate, PTU, iodides |
front 56 Thiocyanate ions primarily decrease which thyroid process? | back 56 B. Iodide trapping |
front 57 Chronic blockade of thyroid secretion by thiocyanate can lead
to: | back 57 D. Goiter |
front 58 Which drug prevents thyroid hormone formation from iodides and
tyrosine? | back 58 A. Propylthiouracil |
front 59 Iodides in very high concentration most consistently: | back 59 C. Decrease all thyroid activity phases |
front 60 A patient is scheduled for thyroidectomy in 3 weeks. Why give iodide
2–3 weeks pre-op? | back 60 B. Decrease necessary surgery amount |
front 61 The most common form of hyperthyroidism is: | back 61 D. Graves’ disease |
front 62 Graves’ disease is best explained by: | back 62 A. TSIs activate TSH receptor cAMP |
front 63 Hyperthyroidism arising within thyroid tissue that secretes large
hormone quantities is: | back 63 A. Thyroid adenoma |
front 64 A patient with excess thyroid hormone most likely reports: | back 64 B. High excitability |
front 65 A patient with thyrotoxicosis most characteristically
develops: | back 65 A. Heat intolerance |
front 66 A hyperthyroid patient develops frequent loose stools. This symptom
is best described as: | back 66 D. Varying degrees of diarrhea |
front 67 Which finding best reflects hyperthyroid skeletal muscle
effects? | back 67 B. Muscle weakness |
front 68 A patient is “exhausted but can’t sleep.” This pattern best
fits: | back 68 C. Fatigue with insomnia |
front 69 A hyperthyroid patient’s hands shake when holding a cup. This
is: | back 69 A. Tremor of hands |
front 70 “Protrusion of eyeballs” in hyperthyroidism is called: | back 70 D. Exophthalmos |
front 71 Exophthalmos accompanied by circulating immunoglobulins
suggests: | back 71 B. Autoimmune process |
front 72 The most accurate diagnostic test for hyperthyroidism listed here
is: | back 72 C. Free thyroxine level |
front 73 Which test is specifically noted as measured by
radioimmunoassay? | back 73 A. Serum TSH concentration |
front 74 In suspected Graves disease, which antibody assay is noted as
measured by radioimmunoassay? | back 74 D. Thyroid-stimulating immunoglobulin |
front 75 The most direct treatment for hyperthyroidism is: | back 75 B. Surgical thyroid removal |
front 76 A hyperplastic thyroid is treated most directly with: | back 76 C. Radioactive iodide therapy |
front 77 The autoimmune cause of hypothyroidism is: | back 77 A. Hashimoto’s disease |
front 78 Progressive deterioration and fibrosis of the thyroid gland is most
consistent with: | back 78 D. Thyroiditis |
front 79 In regions with insufficient iodine intake, people commonly
develop: | back 79 C. Endemic goiters |
front 80 A colloid goiter can result from which abnormality? | back 80 A. Deficient iodide-trapping mechanism |
front 81 A colloid goiter can result from which abnormality? | back 81 B. Deficient peroxidase system |
front 82 A colloid goiter can result from which abnormality? | back 82 D. Deficient coupling of iodotyrosines |
front 83 A colloid goiter can result from which abnormality? | back 83 C. Deiodinase enzyme deficiency |
front 84 Some foods contain substances with PTU-like activity causing
TSH-stimulated thyroid enlargement. These are: | back 84 B. Goitrogenic substances |
front 85 An adult has near-total thyroid hormone loss with swelling and a
baggy face. This condition is: | back 85 B. Myxedema |
front 86 The edema in myxedema is best explained by excess
interstitial: | back 86 D. Hyaluronic–chondroitin protein gel |
front 87 Which hypothyroid test pattern best matches classic teaching? | back 87 A. Low free T4, high TSH |
front 88 Proper long-term treatment for primary hypothyroidism is: | back 88 C. Thyroxine administration |
front 89 Extreme hypothyroidism during childhood causing poor growth and
mental retardation is: | back 89 D. Cretinism |
front 90 The two major categories of cretinism are: | back 90 B. Congenital and endemic |
front 91 A neonate with cretinism must receive which therapy early to prevent
deficits? | back 91 A. Iodine or thyroxine early |
front 92 In cretinism, which growth pattern best explains “short, stocky,
obese” appearance? | back 92 C. Skeletal more inhibited |
front 93 Which pairing best matches thyroid outputs and functions? | back 93 D. T3/T4 raise rate, calcitonin lowers calcium |
front 94 Sodium-iodide symporter is located on the: | back 94 A. Basolateral plasma membrane |
front 95 Energy driving iodide uptake via NIS comes from: | back 95 C. Na-K ATPase sodium gradient |
front 96 As thyroid activity increases, intracellular iodide becomes: | back 96 D. Higher than blood |
front 97 Which hormone increases NIS activity? | back 97 B. Thyroid-stimulating hormone |
front 98 Thyroid epithelial cells secrete into follicle a protein providing
tyrosines for iodination: | back 98 C. Thyroglobulin |
front 99 Two organelles key for thyroglobulin synthesis/secretion are: | back 99 B. Rough ER and Golgi |
front 100 In presence of hydrogen peroxide, which enzyme converts iodide to
iodine? | back 100 D. Peroxidase |
front 101 After coupling, which hormone remains part of the thyroglobulin
molecule? | back 101 A. Thyroxine (T4) |
front 102 The storage form of thyroid hormone not released into blood
is: | back 102 C. Thyroglobulin |
front 103 Release of T3/T4 from thyroglobulin begins with: | back 103 B. Pinocytosis of colloid |
front 104 The enzymatic step liberating free T3/T4 uses: | back 104 D. Lysosomal proteases |
front 105 Luminal membrane protein mediating thyroglobulin
endocytosis/transcytosis is: | back 105 A. Megalin |
front 106 The specific glycosaminoglycans increased in myxedema
include: | back 106 D. Hyaluronic acid and chondroitin sulfate |
front 107 In primary hypothyroidism, which lab change is expected? | back 107 B. Increased TSH secretion |
front 108 The “baggy face” of severe hypothyroidism is most directly due
to: | back 108 C. Interstitial glycosaminoglycan gel |
front 109 Which thyroid hormone binds plasma proteins most avidly? | back 109 C. T4 |
front 110 Higher plasma-binding affinity best matches which release
pattern? | back 110 D. T4 6 days; T3 1 day |
front 111 A thyroid preparation is slower acting with longer latent period and
longer half-life. Which hormone is it? | back 111 A. T4 |
front 112 Thyroid hormone increases functional activity throughout the body
primarily by: | back 112 C. Increasing gene transcription |
front 113 The thyroid hormone that directly binds intracellular thyroid
receptors to drive transcription is: | back 113 B. T3 |
front 114 Over 90% of thyroid hormone bound to receptors is: | back 114 A. T3 |
front 115 The TR/RXR complex initiates transcription by binding: | back 115 B. TREs |
front 116 Increased “leakiness” of which ion most raises heat production and
BMR? | back 116 A. Na+ |
front 117 A child becomes tall early; bones mature rapidly; epiphyses close
early; adult height may be reduced. Most consistent thyroid
state: | back 117 D. Hyperthyroidism |
front 118 Thyroid hormone effect on carbohydrate and fat metabolism is: | back 118 C. Increases both pathways |
front 119 In hypothyroidism, expected lipid pattern is: | back 119 A. ↑chol, ↑PL, ↑TG; ↓FFA |
front 120 Thyroid hormone lowers cholesterol partly by: | back 120 B. ↑bile secretion, ↑fecal loss |
front 121 Thyroid hormone lowers LDL largely by increasing hepatic: | back 121 D. LDL receptor expression |
front 122 Normal thyroid hormone effect on free fatty acids is: | back 122 A. Increases free fatty acids |
front 123 Excess thyroid hormone raises vitamin requirements mainly because
it: | back 123 C. Increases enzyme production |
front 124 Which hyperthyroid pattern is most expected? | back 124 B. ↑BMR, ↓weight |
front 125 In hyperthyroidism, blood flow and cardiac output typically: | back 125 D. Increase both |
front 126 In hyperthyroidism, heart rate and contractile strength: | back 126 A. Increase both |
front 127 Thyroid hormone has little net effect on mean arterial pressure
because: | back 127 C. Systolic rises, diastolic falls |
front 128 Which combination best maintains mean arterial pressure with thyroid
hormone? | back 128 D. ↑systolic, ↓diastolic; ↑pulse pressure |
front 129 Excess thyroid hormone effect on respiration is: | back 129 B. Increases rate and depth |
front 130 Excess thyroid hormone effect on GI motility is: | back 130 A. Increased motility |
front 131 Hyperthyroidism effect on CNS most resembles: | back 131 D. CNS stimulation, anxiety |
front 132 Hyperthyroidism effect on muscle mass is: | back 132 C. Decreased via catabolism |
front 133 A patient with chronic diarrhea is more consistent with: | back 133 B. Hyperthyroidism |
front 134 A patient with constipation is more consistent with: | back 134 D. Hypothyroidism |
front 135 Hyperthyroid tremor is best described as: | back 135 A. Fine “paper vibration” tremor |
front 136 Parkinson tremor is best described as: | back 136 C. Coarse shivering tremor |
front 137 A patient sleeping 12–14 hours daily most suggests: | back 137 A. Hypothyroidism |
front 138 del | back 138 del |
front 139 In men, lack vs excess thyroid hormone most classically
causes: | back 139 D. Lack libido loss; excess impotence |
front 140 In women, thyroid hormone deficiency is associated with: | back 140 C. Menorrhagia, polymenorrhea, irregular |
front 141 In women, excess thyroid hormone is associated with: | back 141 B. Oligomenorrhea and amenorrhea |
front 142 TSH stimulation increases which thyroid process? | back 142 A. Iodide pump activity |
front 143 TSH stimulation increases which release-related step? | back 143 D. Increased thyroglobulin proteolysis |
front 144 Chronic TSH stimulation increases: | back 144 B. Thyroid cell number increases |
front 145 TSH increases hormone synthesis partly by: | back 145 A. Increasing tyrosine iodination |
front 146 TSH activates thyroid follicular cells primarily via: | back 146 C. cAMP second messenger |
front 147 TRH enters hypophysial portal blood from the: | back 147 A. Median eminence |
front 148 TRH triggers TSH release using: | back 148 B. PLC → Ca2+ + DAG |
front 149 If the hypophysial stalk is cut, cold tolerance is preserved
because: | back 149 C. Hypothalamus increases TRH |
front 150 Which antithyroid drug decreases iodide trapping? | back 150 A. Thiocyanate |
front 151 Which antithyroid drug blocks peroxidase and coupling? | back 151 B. Propylthiouracil |
front 152 Which therapy decreases thyroid activity and size? | back 152 D. High-dose iodides |
front 153 Autoimmune hyperthyroidism with TSIs against TSH receptors
is: | back 153 B. Graves disease |
front 154 A tumor secretes thyroid hormone, suppressing pituitary TSH. This
is: | back 154 A. Thyroid adenoma |
front 155 Exophthalmos can endanger vision by compressing the: | back 155 D. Optic nerve |
front 156 Exophthalmos in thyrotoxicosis is caused mainly by: | back 156 C. Retro-orbital edema + myopathy |
front 157 In classic thyrotoxicosis, plasma TSH is typically: | back 157 A. Absent or very low |
front 158 Autoimmune destruction causing thyroiditis and goiter is: | back 158 B. Hashimoto disease |
front 159 Iodine deficiency causes goiter primarily through: | back 159 C. Low T3/T4 → high TSH |
front 160 Goiter in people without iodine deficiency is: | back 160 D. Idiopathic nontoxic colloid goiter |
front 161 Which food contains goitrogenic substances? | back 161 A. Cabbages or turnips |
front 162 Froglike husky voice with diffuse edema suggests: | back 162 B. Myxedema |
front 163 Endemic cretinism most commonly results from: | back 163 C. Dietary iodine deficiency |