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1. FRANCIS ANTHONY B. LOSLOSO, RN
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2.  Shape: Butterfly/ shield-shaped organ
 Location: Lower anterior middle neck
 2 lateral lobes connected by an isthmus
 Size: about 5cm long and 3 cm wide
 Weight: about 30g
 High blood flow (5mL/min/gram of thyroid tissue) 5x blood flow to the liver
 High metabolic activity
 Three hormones:
 Thyroxine T4
 Triiodothyronine T3
 Calcitonin
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3.  T3-T4 make up thyroid hormone- amino acids containing iodine molecules bound to
the amino acid structure
 Synthesized and stored bound to proteins in the cells of the thyroid gland until
needed for release into the bloodstream
 About 75% of bound thyroid hormone is bound to thyroxine-binding globulin (TBG)
 Remaining bound thyroid hormone is bound to the thyroid-binding prealbumin and
albumin
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4.  Burns food (calories)
 Stimulates sympathetic nervous system
 Increases heart rate, blood pressure and temperature
 Determines how fast food travels through digestive system
 Bound to thyroxine-binding globulin and other plasma proteins for transport in the
blood
 Free hormones enters cells and regulates the pituitary feedback mechanism
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5.  Increases metabolism and protein synthesis
 Necessary for growth and development in children including mental development
and attainment of sexual maturity
 Actions are mediated by T3
 In the cell, T3 binds to a nuclear receptor, resulting in transcription of specific
thyroid hormone response genes
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6.  Increases the metabolism of all body tissues except retinas, spleen, testes and lungs
 Basal metabolic rate can increase by 60-100% above normal when large amounts of
T4 are present
 Rate of glucose, fat and protein use increases
 Lipids are mobilized from adipose tissue, and the catabolism of cholesterol by the
liver is increased
 Muscle proteins are broken down and used as fuel
 Absorption of glucose from GIT is increased
 Increased metabolic rate speeds up the use of vitamins and tends to cause vitamin
deficiency
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7.  Due to increase metabolism, there is a rise in oxygen consumption and production of
metabolic end products
 Increase in vasodilation
 Increased blood volume, cardiac output and ventilation as a mean of maintaining
adequate blood flow and oxygen delivery to body tissues
 Enhanced cardiac rate and contractility
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8.  Increase motility and production of gastrointestinal secretions that often results in
diarrhea
 Increase in appetite and food intake accompanies the higher metabolic rate that
occurs with increased thyroid hormone levels
 Weight loss occurs due to increased use of calories
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9.  Elevation in hormones
 Vigorous
 Fine muscle tremor due to increased sensitivity of the neural synapse in spinal cord that
controls muscle tone
 Low levels- sluggish
 *Hormone is necessary for brain development in infants.
 It enhances cerebration in the hyperthyroid state, causes extreme nervousness,
anxiety and difficulty sleeping.
 Over activity of the sympathetic division of the autonomic nervous system suggests
hyperthyroidism (tachycardia, palpitation, tremors)
 Tremor, restlessness, anxiety and diarrhea also may reflect autonomic nervous
system imbalances
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10.  Synthesis of hormones
 Iodine (Iodide) containing foods- absorption in the blood through GI tract- iodide
converts to iodine molecules- reacts with tyrosine- formulation of thyroid hormones
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11.  Controlled by TSH or thyrotropin from the Anterior Pituitary Gland
 TSH-controls rate of thyroid hormone release
 Thyroid hormone in blood determines release of TSH
 Decrease TH- release of TSH increases= increase output of T4 and TSH
 Thyrotropin-releasing hormone (TRH) secreted by hypothalamus exerts modulating
influence on the release of TSH from the pituitary
 Decrease temperature may lead to increased secretion of TRH= elevated secretion
of TH
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12.  Hypothalamus producing thyrotropin-releasing
hormone (TRH) ->
 Anterior pituitary gland- thyroid stimulating hormone
(TSH) ->
 Increases overall activity of the thyroid gland by
increasing thyroglobulin breakdown and the release of
thyroid hormone from follicles into the bloodstream ,
activating the iodide pump- increasing oxidation of iodide
and the coupling of iodide to tyrosine and increasing the
number and the size of the follicle cells
*Increased levels of TH act in the feedback inhibition of
TRH or TSH
*Cold exposure is one of the strongest stimuli for increase
TH production an probably is mediated through TRH from
the hypothalamus
*Various emotional reactions also can affect the output of
TRH and TSH and therefore indirectly affect secretion of TH
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13.  Thyroid hormone- control cellular metabolic
activity
 T4- weak hormone- maintains body metabolism
in steady state
 Converted to T3 before it can act physiologically
 T3- 5x as potent as T4, more rapid metabolic
action
 Active form of the hormone
 Accelerates metabolic process by increasing
level of specific enzymes that contribute to
oxygen consumption and altering the
responsiveness of tissues to other hormones
 Influence cell replication, important in brain
development
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14.  Thyrocalcitonin
 Secreted in response to high plasma levels of calcium
 Reduces plasma level of calcium by increasing its bone deposition
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15. FRANCIS ANTHONY B. LOSLOSO, RN
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16.  Enlargement of the thyroid gland that does not result from a neoplastic or
inflammatory process
 It may impair the ability of the thyroid gland to secrete sufficient quantities of
active hormones
 Thyroid gland increases in mass and cellular activity to
overcome mild or moderate impairment of hormone synthesis
 Normal FT4, FT3, TSH in the blood
 Clinical manifestations:
 Dysphagia
 Dyspnea
 Painful swelling
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17.  Subacute or de Quervain’s Thyroiditis
 Viral
 S/sx- sore throat, malaise, odynophagia, dysphagia, pain in thyroid gland, tenderness
 Chronic Thyroiditis
 Self-limited bout of thyrotoxicosis, painless thyroiditis
 Hashimoto’s thyroiditis
 Autoimmune thyroiditis
 Associated with Grave’s disease
 Mediated by cellular and humoral immune factors
 S/sx- gradual thyroid enlargement, pressure in the throat, dysphagia, hoarseness
 Riedel’s struma
 Rare, aka invasive fibrous thyroiditis
 S/sx- pressure secondary to gland enlargement, SOB, cough
 Infectious thyroiditis
 Acute (Strep Haemolyticus, Staph Aureus, Pneumococcus)- fever, chills, pain, sweeling
 Chronic (TB may occur in TG)- diffuse enlargement
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18.  Papillary adenocarcinoma
 Most common, least aggressive
 Follicular adenocarcinoma
 Second most common, more aggressive
 Hurthle cell carcinoma
 Variants of follicular or papillary CA
 Medullary carcinoma
 10% of malignant tumors, early mets to cervical and mediastinal lymph node
 Undifferentiated carcinoma
 Aggressive lesion, spreads rapidly and early beyond the thyroid capsule and
regional lymph nodes to involve deep muscles and other soft tissues of the neck
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20.  Excessive production of thyroid hormones
 Causes:
 Too much iodine
 Graves disease
 (autoimmune- body produces thyroid immunoglobulin)- most common
 Toxic nodular goiter (nodular growths produce excessive thyroid hormones
 Thyroid replacement medication toxicity
 Autonomous toxic nodules
 Thyroiditis
 Tumors
 Life threatening complications: Thyroid storm
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21.  Hyperthyroidism + goiter + opthalmopathy
 Autoimmune
 Abnormal stimulation of thyroid gland by thyroid
stimulating antibodies
 May act with mytasthenia gravis and pernicious anemia
 Opthalmopathy- cytokine mediated activation of
fibroblast in orbital tissue behind eyeballs, tethering of
extraocular muscles leading to diplopia, visual loss and
corneal ulceration
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22. EVERYTHING IS HIGH, FAST AND WET
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23.  Signs and symptoms
 Weight loss (burning excessive
calories)
 Increased appetite
 Heat intolerance
 Goiter (Grave’s disease)
 Restlessness
 Irritable overstimulation of SNS
 Tachycardia
 Atrial arrhythmias
 Palpitation
 Wide pulse pressure
 Systolic murmurs
 Cardiac Failure/ Congestive heart
failure
 Diarrhea
 Unable to focus
 Oily and diaphoresis
 Fine and silky hair
 Nervousness
 Fine tremor
 Hyperreflexia
 Menstrual problem
 Opthalmopathy
 Lid lag
 Infrequent blinking
 Failure to wrinkle
the brow on upward gaze
 Stare
 Exopthalmos
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24.  Cardiac complications
 Tachycardia
 Arrhythmia
 Congestive heart failure
 Cardiac arrest
 Malignant exophthalmos
 Thyrotoxic Crisis/ Thyroid storm
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25.  Life threatening complication that can develop in Hyperthyroidism
 Fulminating increase in all the signs and symptoms of hyperthyroidism
 Predisposing factors: Infection, Surgery
 Marked irritability
 Severe hyperpyrexia
 Tachycardia
 Arrhythmias
 Vomiting and Diarrhea
 Delirium and Coma
 Shock and Death
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27.  Low production of thyroid hormones
 Classification:
 Primary- caused by malfunction of thyroid gland
 Secondary- pituitary malfunction
 Causes:
 Not enough iodine
 Hashimoto’s Thyroiditis (autoimmune- body attacks thyroid gland)
 Anti-thyroid medications (PTU, Tapazole)
 Pituitary tumor
 Life threatening complications: Myxedema coma
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28.  Signs and symptoms
 Weight gain
 Cold intolerance
 Possible goiter (Hashimoto’s)
 Extremely tired and fatigued
 Bradycardia
 Constipation
 Memory loss
 Myxedema: swelling of skin (eyes and face) waxy appearance
 Dry skin
 Depression
 Menstrual problem
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29. EVERYTHING IS LOW, SLOW AND DRY
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30.  At birth
 Untreated hypothyroidism
 Transient hypothyroidism
 Fetal and infant thyroids are sensitive to iodine excess
 Iodine crosses placenta and mammary gland and readily absorbed in infant skin
 Signs and symptoms:
 Dwarfism
 Mental retardation
 Failure to thrive
 Umbilical hernia
 Enlarged tongue
 Hyporeflexia
 Hoarse cry
 Constipation
 Somnolence
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31.  Signs and symptoms:
 Lethargy
 Constipation
 Cold intolerance
 Menorrhagia
 Weight gain
 Poor appetite
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32.  Life threatening complication of hypothyroidism
 Can be precipitated by acute illness, rapid withdrawal of
thyroid hormones, anesthesia, surgery, hypothermia and use of sedatives
 3 major aspects
 Carbon dioxide retention with hypoxia
 Fluid and electrolyte imbalance
 Hypothermia
 Signs and symptoms
 Bradycardia
 Hypotension
 Hypothermia
 Hypoglycemia
 Hyponatremia
 Respiratory failure
 Comatose
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36.  Produces parathormone
 PTH regulates calcium and phosphorus
balance
 PTH elevates serum calcium levels by
withdrawal of calcium from bones
 Low serum calcium levels stimulate PTH
release
 PTH:Calcium- direct proportion
 PTH:Phosphorus- inverse proportion
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37.  Hyposecretion of parathormone
 Cause:
 Thyroidectomy
 Signs and symptoms
 Hypocalcemia- increases neuromuscular excitability
 Hyperphosphatemia
 Signs of tetany
 Dysrhythmias, carpopedal spasm, dysphagia, muscle and
abdominal cramps, numbness and tingling of the face,
 Chvostek, Trousseau, seizure, visual disturbances, wheezing, dyspnea
 Hypotension
 Anxiety, irritability, depression
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38.  Hypersecretion of parathormone
 High serum calcium levels and bone demineralization
 Signs and symptoms
 Hypercalcemia- decreases neuromuscular excitability
 Hypophospathemia
 Fatigue and muscle weakness
 Skeletal pain and tenderness
 Bone deformities that result in pathologic fracture
 Anorexia, nausea, vomiting, epigastric pain
 Weight loss
 Constipation
 Hypertension
 Dysrhythmias
 Renal stone
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