Thyroid Hormone

THYROID HORMONE
powerpoint presentation by: D. C. MIKULECKY
PROFESSOR OF PHYSIOLOGY

THE THYROID GLAND

* OVER TRACHEA
* TWO LARGE LATERAL LOBES CONNECTED BY AN ISTHMUS
* 15 to 20 g
* FUNCTIONAL UNIT IS THE FOLLICLE: EPITHELIAL CELLS AROUND A HOLLOW VESSICLE FILLED WITH THYROGLOBULIN

THE THYROID HORMONES

* THYROGLOBULIN: STORAGE FORM BINDS HORMONES
* TETRAIODOTHYRONINE
* TRIIODOTHYRONINE
* IODINE REQUIRED FROM DIETARY INTAKE

THYROID HORMONES
THYROID HORMONE SYNTHESIS

* DEPENDENT ON IODINE (IODINE PUMP CONCENTRATES IODINE IN CELLS)
* DEPENDENT ON TYROSINE
* PARTIALLY SYNTHESIZED (THYROGLOBULIN) EXTRACELLULARLY AT LUMINAL SURFACE OF FOLLICULAR CELLS AND STORED IN FOLLICULAR LUMEN

EFFECTS OF IODINE

* DURING IODINE DEFICIENCY, HORMONE SYNTHESIS IS IMPAIRED
* EXCESS IODINE ALSO INHIBITS SYSNTHESIS

THYROID HORMONE SECRETION

* WITH TSH STIMULATION, ENDOCYTOSIS BRINGS THE THYROGLOBIN BACK INTO FOLLICULAR CELLS
* THYROGLOBULIN IS DEGRADED TO T3 AND T4

THYROID HORMONE’S EFFECTS

* METABOLIC RATE: INCREASED BMR
* CALOROGENIC: INCREASED HEAT PRODUCTION(OXIDATIVE METABOLISM)
* SYMPATHOMIMETIC: FLIGHT OR FIGHT
* CARDIOVASCULAR:INCREASES RESPONSIVENESS OF HEART
* GROWTH: ESSENTIAL FOR NORMAL GROWTH OF SKELETAL SYSTEM (PERMISSIVE OR SYNERGYSTIC WITH GH, INSULIN-LIKE GROWTH FACTOR), CNS, ANS
* NERVOUS SYSTEM:DEVELOPMENT AND ADULT ACTIVITY

METABOLIC EFFECTS OF THYROID HORMONE

* CALOROGENIC EFFECT: INFLUENCES TOLERENCE TO COLD, AVAILABILITY OF ATP
* CARBOHYDRATE METABOLISM: INCREASED GLUCOSE ABSORPTION FROM GUT,GLCOGENOLYSIS, GLUCONEOGENESIS, GLUCOSE OXIDATION.
* LIPID METABOLISM: LIPOGENESIS IN ADIPOCYTES, IN COORDIMNATION WITH BLOOD GLUCOSE LEVELS

CONTROL OF FUEL METABOLISM

* GLYCOGENESIS
* GLYCOGENOLYSIS
* GLUCONEOGENESIS
* PROTEIN SYNTHESIS
* PROTEIN DEGRADATION
* FAT SYNTHESIS
* FAT BREAKDOWN


GLYCOGENESIS

* GLYCOGEN IS A BRANCHED POLYMER OF GLUCOSE STORED IN THE LIVER AND MUSCLE CELLS
* SYNTHESIS IS BY SEPARATE PATHWAY FROM BREAKDOWN
* HIGHLY REGULATED BY INSULIN

GLYCOGENOLYSIS

* BREAKDOWN OF GLYCOGEN STORES INTO GLUCOSE
* REGULATES BLOOD GLUCOSE BETWEEN MEALS
* HOMONALLY CONTROLLED (GLUCAGON, EPINEHRINE, NOREPINEPHRINE AND CLUCOCORTICOIDS) AMPLIFIED BY THYROID HORMONE

GLUCONEOGENESIS

* PRECURSORS ARE 3 AND 4 CARBON COMPOUNDS
* VIA FRUCTOSE PHOSPHATE
* GLUCAGON CONTROLLED AIDED BY THYROID HORMONE
* MAIN PRECURSOR ALANINE AND OTHER AA


PROTEIN DEGRADATION

* USUALLY BALANCED BY SYNTHESIS
* NO ENERGY STORES IN FORM OF PROTEIN
* CAN BE ENHANCED BY GLUCAGON AND THYROID HORMONES LEADING TO GLUCONEOGENESIS

THYROID HORMONE EFFECTS ON NITROGEN METABOLISM

* ENHANCES BOTH SYNTHESIS AND DEGRADATION OF PROTEINS
* EXCESS HORMONE PROMOTES DEGREDATION

FAT SYNTHESIS

* GLUCOSE - FATTY ACID CYCLE
* FATTY ACIDS PRODUCED CONSTANTLY IN ADIPOSE TISSUE.
* BECOME FFA OR BECOME TRIGLYCERIDES DEPENDING ON -GLYCEROL PHOSPHATE FROM GLUCOSE OXIDATION
* NEED OPTIMAL AMOUNTS OF THYROID HORMONE

GLUCOSE - FATTY ACID CYCLE

THYROID AND TEMPERATURE REGULATION

* T3 IS THE DOMINANT FORM INVOLVED
* EXPOSURE TO COLD CAUSES T4 CONVERSION TO T3 .
* PROMOTES CALOROGENIC EFFECT (LONG TERM COLD ADAPTATION)
* SHORT TERM EFFECTS DUE TO SYMPATHETIC MIMETIC EFFECTS AND THE SHIVERING RESPONSE OF MUSCLES

REGULATION OF THYROID SECRETION
EFFECTS OF TSH
TSH MODE OF ACTION
ABNORMALITIES OF THYROID FUNCTION
THYROID HORMONE.ppt

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Hyperthyroidism

Hyperthyroidism
Powerpoint presentation by: Jessica Stevens

Actions of the thyroid
o Controls body temperature
o How body burns calories
o Controls how fast food moves through digestive tract
o Muscle strength
Thyroid hormones:
o T3-thyroxine
o T4-triiodothyronine
o Calcitonin

Hyperthyroidism is present when the thyroid gland is over secreting hormones.

Diarrhea and weight loss
Eye problems
Enlarged thyroid gland
Hair and skin changes
Heat intolerance
Heart palpitations
Clubbing
Menstrual cycle changes
Muscle weakness
Easily bruised
Nervousness
Restlessness
Anxiety
Irritability
Sleeplessness or insomnia
Exhaustion




Early diagnosis is key to treatment and recovery.

How do we diagnosis these disorders??
o Thyroid stimulation hormone (TSH) test
+ Normal levels of TSH are 0.4-4.5milliunits/L.
o Thyroid hormone test
+ In adults, a normal total T3 level is 80-230 ng/dL. Total T4 levels should be at 5-14 mcg/dL.
Grave’s disease.
A benign nodule on the thyroid.
Thyroiditis.
Taking too much of the synthetic thyroid hormone.

FEMALES…

With Grave’s Disease, the immune system begins to attack the thyroid and produces antibodies that mimic TSH.
Women are more likely to develop Grave’s disease.
Hereditary and environmental influences.
Radioactive iodine
o Typical treatment is 3-12 millicuries.
o However, this treatment can cause hypothyroidism.
o It must also be followed by thyroid replacing hormones.
Beta-Blockers
Antithyroid medication-Propylthiouracil (PTU) or Tapazole

Hypothyroidism is present when the thyroid gland is producing little or no thyroid hormones.
Cold intolerance
Slow digestion
Weight gain
Fatigue
Thin, coarse hair
Brittle fingernails
Muscle aches
Dizziness
Ringing in ears
Numbness
o Carpal tunnel
Poor memory
Skin changes
Voice changes
Milky discharge from breasts

Hypothyroidism can be linked to psychiatric depression.
Some symptoms found are:

Paranoia
Aural and Visual hallucinations
Hashimoto’s thyroiditis
Treatment for hyperthyroidism
Congenital hypothyroidism
Radiation therapy given to the head and/or neck
Side-effect hypothyroidism
Thyroid replacement pills-most common
Some medicines can cause hypothyroidism.
Stop the medication and symptoms should cease.

Cronin, Colleen. (2005) Hyperthyroidism.
Hyperthyroidism.ppt

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Evaluation of Thyroid Nodules

Evaluation of Thyroid Nodules
Powerpoint presentation by: Eric Oliver

Objectives

* Discuss Common Causes of Thyroid Nodules
* Highlight Application of Imaging Studies in Evaluation of the Thyroid Nodule

The Thyroid Nodule
Causes of Thyroid Nodularity
Case 1
Low TSH
Radionuclide Scanning
Scintigraphy
Cold Nodules
Scintigraphy
Hot Nodules
Limitations of Scintigraphy

Case 2
Ultrasonography
Normal Right Thyroid Lobe
Goiter
Incidentalomas
Fine-Needle Aspiration Biopsy
FNAB Limitations
Ultrasound Guided FNAB

Case 3
Take Home Points
References

Evaluation of Thyroid Nodules.ppt

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Hypothyroidism - Signs and Symptoms

Hypothyroidism - Signs and Symptoms
Powerpoint presentation by: Donald L. Gordon, MD

Hypothyroid Face
Faces of Clinical Hypothyroidism
Graves' Disease
Clinical Characteristics of Goiter in Graves’ Disease
Clinical Characteristics of Exophthalmos
Clinical Differentiation of Lid Retraction from Proptosis
Lid Lag in Thyrotoxicosis
Clinical Characteristics of Localized Myxedema
Graves’ Disease - Localized Myxedema
Thyroid Acropachy
HCG-mediated thyrotoxicosis
Integumentary System in Thyrotoxicosis
Onycholysis of Thyrotoxicosis
Cardiorespiratory System in Thyrotoxicosis
Gastrointestinal System in Thyrotoxicosis
Gynecomastia and Thyrotoxicosis
Neuromuscular System in Thyrotoxicosis
Hyperactive Deep Tendon Reflexes in Thyrotoxicosis
Frequency of Neuromuscular Disorders
Associated with Thyrotoxicosis
Thyrotoxic Periodic Paralysis
Embryology of the Thyroid Gland
Lingual Thyroid (failure of descent)
Disorders In Patients Who Received Head and/or Neck Radiation
Differential Diagnosis of a Painful Thyroid

Hypothyroidism.ppt

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The Thyroid Gland

The Thyroid Gland
Powerpoint presentation by: Felix E. Grissom, Ph.D
Howard University

Thyroid Gland: Hormones and Iodine Metabolism
Thyroid Hormone:Transport
Thyroxine and its precursors: Activity
Thyroid Hormone Feedback Regulation
Regulation by Energy Intake/Adipose Stores
T3 & T4 Control Pathways & Diseases from Malfunction
Thyroid Gland Summary


Thyroid Gland.ppt

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THYROID DISORDERS

THYROID DISORDERS
Powerpoint presentation by: Abdelaziz Elamin. MD, PhD, FRCPCH
Professor of Child Health
Consultant Pediatric Endocrinologist
Sultan Qaboos University, Oman


Hypothyroidism-epidemiology
Etiology
Kilpatrik grading of goitre
Thyroid gland
Overview
Thyroid hormones
Tsh
Thyroid hormones
Thyroxine (t4)
Functions of thyroxine
Clinical features
Occasional features
Associations
Goitrogens
Congenital hypothyrodism
Diagnosis
Labrotary findings
Imaging tests
Treatment
Thyroid function tests
Prognosis
Myxoedmatous coma

Thyroid Disorders.ppt

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Thyroid Cancer

Thyroid Cancer
PowerPoint presenation by Christopher Muller (MS4)
Faculty disscussants: Dr. Byron J. Bailey and Dr. Anna M. Pou


Intoduction
Statistics of Thyroid Cancer
History
Risk factors
Evaluation of the thyroid Nodule
Evaluation of the Thyroid Nodule
Evaluation of the Thyroid Nodule
(Ultrasonography)
Evaluation of the Thyroid Nodule
(Radioisotope Scanning)
Specific uses of thyroid scanning
Evaluation of the Thyroid Nodule
(Fine-Needle Aspiration)
Evaluation of the Thyroid Nodule
(Thyroid-Stimulating Hormone Suppression)
Classification of Malignant Thyroid Neoplasms
Well-Differentiated Thyroid Carcinomas (WDTC) - Papillary, Follicular, and Hurthle cell
WDTC - Papillary Carcinoma
WDTC - Follicular Carcinoma
WDTC - Hurthle Cell Carcinoma
WDTC - Prognosis
Medullary Thyroid Carcinoma
Anaplastic Carcinoma of the Thyroid
Management (WDTC) - Papillary and Follicular
Medullary Thyroid Carcinoma (Management)

Thyroid Cancer .ppt

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