This Learning Module takes you from an overview of the function of the thyroid gland to then hone in on the physiology of synthesis and secretion of thyroid hormone from amino acids and iodide, to its circulation in highly bound form in the circulation. Regulation of the concentrations are tightly regulated by the hypothalamus and pituitary. Understanding of diagnostic tests and treatment for the conditions of hypothyroidism and hyperthyroidism are discussed.
Thyroid, Deiodination, Iodine, Hypothalamus, Pituitary, Receptors, Hypothyroidism, Hyperthyroidism
The Thyroid Gland:
The thyroid gland is a fascinating organ and has very important and integrated physiological effects on cells and tissues within the body. The following short TED Ed animated video will get you started on your journey towards understanding this organ.
Emma Bryce: How Does the Thyroid Manage your Metabolism?
TED Video and Lesson: this link includes review questions, and deeper thinking questions that you are highly encourage to address
The content link is a short overview animated video from TED Ed. The video reviews the major roles of the thyroid gland. The unit includes review questions and suggested readings
In this section, you will review how the thyroid gland is structured and thyroid hormone is synthesized.
For more information, please read the physiology section within the reference below:
Ferguson, D. C. Thyroid Hormones and Antithyroid Drugs, in Riviere JE, Papich M (eds): Veterinary Pharmacology and Therapeutics, 9th ed., Wiley-Blackwell, pp. 735-770, 2009.
To survey your knowledge comprehension, you may take this QUIZ.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page.
Serum Thyroid Hormone Protein Binding (10:07)
For more details, review the following article:
Ferguson, D.C. Free thyroid hormone measurements in the diagnosis of thyroid disease. in, Bonagura, J., and Kirk, R.W. (eds) Current Veterinary Therapy XII, 1995, pp. 360-363.
Review your understanding with this QUIZ
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page.
Hypothalamic-Pituitary-Thyroid Axis (15:16)
After reviewing the video, check your content comprehension with the associated QUIZ.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page.
In this unit, you will learn about the extrathyroidal metabolism of thyroid hormones. Video: 20:29
To review your understanding, attempt this formative QUIZ.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page.
In this unit, we will learn about the molecular mechanisms of signal transduction by which thyroid hormone acts on cells. Video: 17:33
After viewing the video, review your understanding with this QUIZ.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page.
In this unit, we'll put it all together through an evaluation of the clinical effects of thyroid hormone as evidenced through the diseases of thyroid hormone deficiency and excess, hypothyroidism and hyperthyroidism. Video: 12:08
Following review of these materials, formatively evaluate your understanding by completing this QUIZ.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page.
Screening Tests for Canine Hypothyroidism (16:59):
For more information, consider reviewing the following publication:
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page. (Quiz Not Yet Added)
Confirmation Tests for Canine Hypothyroidism (17:14):
In this unit, you will learn about the common tests used to confirm hypothyroidism in the dog, including free T4 and TSH.
There is no associated Knowledge Survey (quiz) with this unit, but we encourage you to review the Case of the Stunted Puppies in unit 12, and your instructor may have you conduct an analysis of this case.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page. (Quiz Not Yet Added)
Feline Hyperthyroidism
In the attached PDF file of presentation is entitled:
This presentation also contains several case scenarios of feline hyperthyroidism.
Evaluate your understanding of a disease of excess based upon understanding of PHYSIOLOGY!
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page. (Quiz Not Yet Added)
In this unit, we will finally start giving you some medical tools to treat the thyroid disease of excess, hyperthyroidism, caused by autonomous hyperfunctional goiter in the cat. This unit discusses the mechanisms of action and side effects of antithyroid drugs.
Video: 14:36
There is no Knowledge Survey (quiz) associated with this unit at this time.
The brief formative review quiz can be released as a link for the learner to review at the time of their choosing or can be distributed by the link on this page. (Quiz Not Yet Added)
Case of the Stunted Puppies
A 4 year old rat terrier bitch had a litter of pups and 3 were stunted in growth and quite developmentally delayed. The pups were much smaller than "normal" littermates (see Photo 1). They also were difficult to house train. The haircoat of these puppies even at 6 months of age was dominated by guard hairs (i.e. the "puppy coat" was maintained). The haircoat was also lighter in color than the "normal" pups. Please see the photographs which come with the text introduction to the case. There were no serum biochemical abnormalities in the bitch and yet the puppies had an elevated serum cholesterol and a mild anemia with no evidence that immature red blood cells were being produced by the bone marrow in response. Thyroid function tests were performed and are shown below. One of the puppies was such a "poor doer" according to the breeder that the decision was made to euthanize it. The second photo in the case introduction shows the thyroid gland on the lefthand side compared with the kidney on the righthand side.
Photo 1: Rat Terrier Litter: 3 stunted puppies with 1 normal littermate
Photo 2: Gross Cross-Section of Thyroid lobe (left; both glands are grossly enlarged) compared to Kidney
Summary of literature data on diagnostic characteristics of individual and dual combinations of thyroid hormone testing.
from Ferguson, D.C.: Testing for hypothyroidism in dogs. Veterinary Clinics of North America Small Animal 37: 647-669, 2007.
Endocrine Tests for Pup and Bitch
Analyte | Concentration, Pup | Concentration, Bitch | Reference Range |
Total T4 | <0.2 | 1.8 | 1-4 ug/dl |
Free T4 | 7.3 | 38.3 | 12-50 pmol/L |
TSH | 2.33 | 0.1 | <0.7 ng/ml |
CASE ANALYSIS
In outline form, develop an analysis of this case which highlights the connection of case clinical signs and test results to physiology. Highly suggested elements of your analysis should include answers to the following questions. You are encouraged to copy from elements within the case and include multimedia resources in your analysis, but the most important feature for your reviewers will be the extent to which you individualize your explanation, that is use your own words to demonstrate synthesis of the information you found relevant and its connection to normal or perturbed physiology.
This project request should be released following release of the case information as an update to the Community.