Endo 3 Flashcards by Michael McMahan

About 93 % of the active hormones secreted by the thyroid gland is which hormone?

Thyroxine (T4)

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Which thyroid hormone is more potent?

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Which hormone is the active hormone?

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What cells of thyroid gland secretes calcitonin?

Parafollicular cells

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____ is required for thyroid hormone synthesis so thyroid follicular cells actively transport it obtained from the diet

Iodine

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_____ is capable of producing intracellular I– concentrations that are 20–40 times as great as the concentration in plasma (Secondary active transporter)

Na+/I– symporter (NIS)

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What is the name of the channel that brings Cl into T-Thyrocyte cell and secretes iodine out into the colloid (secondary active transporter_

Pendrin

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What enzyme is active in the colloid to iodinate thyroglobulin for transport thru the t-thyrocyte cell back into the blood stream?

Peroxidase

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What enzyme is active in the colloid to iodinate thyroglobulin for transport thru the t-thyrocyte cell back into the blood stream?

Peroxidase

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How do the thyroid hormones get from the T-thyroocytes to the blood?

Simple diffusion

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Colloid is internalized by _____

endocytosis

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____ is a reservoir of thyroid hormones

Colloid

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Is most thyroid bound to proteins or does it circulate freely?

Bound to proteins

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Target cells make active T3 by using enzymes called ____ that remove an iodine from T4

Deiodinases/Iodinases

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Individual target cells can alter their exposure to T3 by regulating their tissue _____ synthesis.

Deiodinase

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If a condition inhibits Deiodinase activity, there could be signs of _____

hypothyroidism

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Which thyroid hormone lasts longer but takes longer to take effect?

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_____ hormones are involved in the following functions: growth, CNS development, increase cardiac output, increase tissue blood outflow, increase heart rate, increase heart strength, increased rate of respiration, increased BMR, increased NA-K ATPase, increased gluconeogenesis, increased glycogenolysis, increased lipolysis, increased protein snthesis

Thyroid hormones

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Which thyroid hormone is the main circulating form responsible for most of the (-) feedback

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Is TSH secretion pulsatile or follow circadian rhythms?

Pulsatile

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When is the most TSH secreted?

Midnight

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When does TSH secretion begin to increase

9 PM

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Which hormone Stimulates carbohydrate metabolism–Causes uptake of glucose by cells–Enhances glycolysis & gluconeogenesis–Increases rate of CHO absorption from G.I. tract•Stimulates proteincatabolism & synthesis •Stimulates fat metabolism9•Stimulates oxygen consumption by most metabolically active tissues.•Increased Basal Metabolic Rate (BMR)–Increases lipid mobilization & oxidation of fatty acids by cells–Required to convert beta carotene to vitamin A (Hypothyroid patients have yellowish skin) –Decreases circulating cholesterol levels (Hypothyroidism associated with hyperlipidemia)

Thyroid hormone

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____ hormones is needed for NS development, decreases reflex time, muscle tremors, feeling of tiredness but difficulty sleeping (decrease), anxiety, worry, and paranoia

Thyroid hormone

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____ hormones acitvate bone formation that causes a need for PTH secretion

Thyroid hormones

_____ hormones have a permisive effect on CV system where there is increased expression of B-adrenergic receptors

Thyroid hormones

____ hormones lead to increased appetite, increased rate of secretion and motility of the GI tract (undersecretion can produce constipation)

Thyroid hormones

____ is an enlarged thyroid that does not indicate functional status

Goiter

Goiter caused by excessive amounts of ____secretion

TSH

High ____ stimulates thyroid to secrete large amounts of thyroglobulin colloid into follicles, resulting in gland enlargement

TSH

_____ is the most common form of hyperthyroidism•An autoimmune disease where antibodies to TSH receptor called thyroid-stimulating immunoglobulins (TSIs) stimulate the thyroid gland to excess•TSI antibodies have prolonged stimulating effect on thyroid gland, lasting as much as 12 hours, in contrast to TSH of ~1 hour•High levels of thyroid hormone secretion caused by TSI suppress anterior pituitary TSH secretion (negative feedback)12 a common disorder affecting 0.5% to 1.2% of the population. There is a female-to-male ratio of 5 to 10:1.” can also occur due to a thyroid adenoma.

Graves’ Disease

Do females or males get Graves' disease more?

Females

Expothalmos, sweating, heat intolerance, muscle wasting, pretibial myxedema, goiter, nervousness, restlessness, emotional instability, insomnia, increased appetite, and weight are symptoms of _____

Hyperthyroidism

___ is treated with Radioactive I 131 thyroid ablation, or Antithyroid Drugs (propylthiouracil or methimazole). –Surgery rarely indicated.•Propanolol (b blocker) given for adrenergic symptoms while awaiting resolution. •L-thyroxine administered to prevent hypothyroidism in patients who have undergone ablation or surgery

Hyperthyroidism

Oral Symptoms of ____ include •Burning Mouth Syndrome (greater likelihood in women > 50 yrs)•Gum disease •Excessive salivation•Weakening of mandible•Increased caries risk

Hyperthyroidism

•Elevated Thyroid Hormone with stressful events (trauma, surgery, severe emotional distress) or serious illness (DKA, MI, etc.). •Symptoms: fever, tachycardia, elevated BP, nausea, vomiting, diarrhea, breathing problems, etc.•In patients with hyperthyroidism or those that exhibit signs/symptoms of it, administration of epinephrine is contraindicated and elective dental care should be deferred.

Thyroid Storm (Thyrotoxicosis)

•Autoimmune reaction against thyroid gland destroys gland rather than stimulating it. •Most common cause of hypothyroidism •Most patients first exhibit autoimmune "thyroiditis,” thyroid inflammation• Inflammation leads to fibrosis of thyroid resulting in decreased secretion of thyroid hormone.

Hashimoto’s Thyroiditis

In ______ states, a goiter is due to an iodine deficiency and no goiter is due to a TSH deficiency

Hypothyroidism

_____ is due to low iodine

Hypothyroidism

Coarse dry hair, loss of lateral eyebrows, weight gain, constipation, lethargy, impaired memory, slow pulse, constipation, and cold intolerance are symptoms of ____

Hypothyroidism

(edema in dermis) Seen in severely hypothyroid patients•Increased quantities of hyaluronic acid and chondroitin sulfate bound with protein plus water accumulate in skin; Dull expressionless faces, with puffiness of eyelids; swollen skin

Myxedema

Thyroid hormones required for postnatal brain maturation. •Results from:–Congenital absence of thyroid gland –Iodine deficient diet (most common cause worldwide); causes physical and mental retardation of neonates; skeletal growth is more inhibited than soft tissue growth

Cretinism

Macroglossia•Dysgeusia•Delayed tooth eruption•Poor wound healing and increased risk of infection (due to decreased activity of fibroblasts)•Increased periodontal disease•Salivary gland enlargement are oral manifestations of ____

Hypothyroidism

Patients with ______ are sensitive to central nervous system depressants and barbiturates, so these medications should be used sparingly.

hypothyroidism

85% of the body’s PHOSPHATE is stored in ____

bones

Only 0.1% of total body CALCIUM is in the ____

EC fluid

If calcium is too ____, neuronal hyper-excitability (tetany) occurs

Too low

If calcium is too ____, neuronal depression occurs

Too high

Where does absorption of calcium and phosphate occur?

Intestines

Where does excretion of calcium and phosphate occur?

Feces in urine

Where is calcium and phosphate temporarily stored?

Bones

• increases Plasma Calcium and decreases Phosphate–Mobilizes calcium from bone–Enhances renal reabsorption of calcium–Increases intestinal absorption of calcium (indirectly)

Parathyroid Hormone (PTH)

Increases Plasma Calcium and Increases Phosphate– is the primary hormone that enhances intestinal absorption of calcium and it also causes absorption of phosphate.

Calcitriol (1,25-dihydroxycholecalciferol or vitamin D3)•

Decreases Plasma calcium and phosphate

Calcitonin

In addition to PTH, bone resorption is stimulated by ___ and ____.

Cortisol and T3

What is the on signal for osteoclasts?

RANKL

What binds to RANKL to decrease osteoclast activity?

OPG

____ affects almost 10 million individuals in the US, though only a small proportion are diagnosed and treated. It occurs when there is an imbalance between bone formation and resorption.

Osteoporosis

Risk factors of ____ include vitamin D deficiency (secondary hyperparathyroidism), inadequate calcium intake (secondary hyperPTH), glucocorticoid medications, reduced physical activity, estrogen deficiency (post-menopausal), cigarette smoking, alcohol,

Osteoporosis

Exercise, physical therapy, estrogen, calcium, Vit D, and Bisphosphonates are treatments for _____

Osteoporosis

Four pea-sized glands on the posterior surface of the thyroid gland.

Parathyroid glands

PTH is secreted by ___ cells in the thyroid

Chief cells

Increases plasma calcium by (1) increasing Intestinal Absorption, (2) decreasing Renal Excretion and (3) increasing Bone resorption.•decreases plasma phosphate by increasing Renal Excretion

PTH

____ ECF Ca concentration Increases rate of PTH secretion, hypertrophy of parathyroid gland, Pregnancy, Rickets, and Lactation

Decreased

_____ ECF Ca2+ concentration leads to ↓activity of parathyroid gland, ↓ size of parathyroid gland: increased vitamin D intake, excess quantities of calcium in the diet, and bone resorption caused by factors other than PTH

Increased

____ increases calcium by Bone Resorption, Reabsorption of Calcium by Renal Tubules which reduces excretion, Converts 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol (Vitamin D/Calcitriol), which causes intestinal calcium absorption.

PTH

____ decreases plasma by Decreased reabsorption by renal tubules leading to increased urinary excretion

PTH

What is the main effect of Vitamin D3

Absorption of Ca and P in intestine

What are the 3 places Vit D3 come from?

Skin, liver, and kidney

Peptide hormone secreted by parafollicular cells (C cells) of the thyroid gland •Released in response to elevated free plasma Ca2+•Lowers plasma Ca2+by decreasing activity of osteoclasts, thus decreasing bone resorption•Not a major controller of Ca2+ in humans

Calcitonin

___ is caused by Excess PTH secretion due to a parathyroid gland tumor•Extreme osteoclastic activity in bones causes cystic bone disease

Primary Hyperparathyroidism

Vit D deficiency in children

Rickets

Vit D deficiency in adults

Osteomalacia

High PTH levels occur as compensation for hypocalcemia not due to primary abnormality of parathyroid glands•Causes of hypocalcemia:–Vitamin D deficiency and Chronic renal disease

Secondary Hyperparathyroidism

Less common-often results from accidental surgical parathyroid gland removal; Hypocalcemia increases membrane Na+permeability leading to neuromuscular excitability & muscle spasms & tetany; spasm of laryngeal muscles obstructs respiration

Primary Hypoparathyroidism

_____ sign is used to detect Hypoparathyroidism: flick facial muscle and look for involuntary muscle spasm (checks for hypocalcemia)

Chovstek's sign

Endo 3 Flashcards

(76 cards)