Thyroid Gland - Anatomy & Physiology - Revision history

Fiorecastro at 17:46, 7 December 2022

2022-12-07T17:46:26Z

Bhavisha: /* Problems associated with the Thyroid Gland */

2016-05-17T20:29:34Z

Problems associated with the Thyroid Gland

Ggaitskell at 06:22, 9 July 2014

2014-07-09T06:22:17Z

Bara at 13:25, 29 June 2012

2012-06-29T13:25:32Z

Bara at 17:29, 3 September 2011

2011-09-03T17:29:42Z

HelenD at 07:46, 2 September 2011

2011-09-02T07:46:19Z

HelenD at 07:46, 2 September 2011

2011-09-02T07:46:02Z

Ctrace: /* Test yourself with the Thyroid Gland Flashcards */

2011-06-06T15:04:05Z

Test yourself with the Thyroid Gland Flashcards

Bara at 12:51, 1 May 2011

2011-05-01T12:51:35Z

Bara at 12:50, 1 May 2011

2011-05-01T12:50:25Z

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 {{review}}
-{{OpenPages}}
+==Webinars==
 [[Category:Endocrine System - Anatomy & Physiology]]
 [[Category:A&P Done]]

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 |powerpoints = [[Endocrine Histology resource|Histology of the Endocrine system]]
 |OVAM = [http://www.onlineveterinaryanatomy.net/content/feline-thyroid-gland-histology Feline Thyroid Gland Histology]
 }}

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 |flashcards = [[Thyroid_Gland_Flash_Cards_- Anatomy & Physiology|Thyroid Gland]]<br>[[Equine Internal Medicine Q&A 21]]
 |powerpoints = [[Endocrine Histology resource|Histology of the Endocrine system]]
 }}

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 ==Introduction==
 The thyroid gland lies in the neck, in front of the upper part of the trachea.  Two types of hormones are produced, which are the iodine containing hormones; '''tri-iodothyronine'''(T3) and '''thyroxine''' (T4). Thyroid hormones regulate the basal metabolic rate and are important in the regulation of growth of tissues, particularly nervous tissue. Release stimulated by TSH from the pituitary. The second type of hormone produced from the thyroid gland is '''[[calcitonin]]''', which regulates blood calcium levels along with parathyroid hormone and acts to reduce blood calcium by inhibiting its removal from bone.
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 {{review}}
 [[Category:Endocrine System - Anatomy & Physiology]]
 [[Category:A&P Done]]

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 :Finally, in the [[Alimentary System Overview - Anatomy & Physiology|'''alimentary system''']], thyroid hormone increases appetite and feed intake, increases secretion of [[Pancreas - Anatomy & Physiology|pancreatic]] enzymes and increases motility.
-===Influence of external factors===
+===Influence of External Factors===
 '''Euthyroid sick syndrome''': concurrent disease such as starvation, sepsis, trauma or stress can cause a depression in basal thyroid levels as a normal response, to minimise the catabolic effects of thyroid hormones.
-This occurs in many species and may lead to false diagnoses of hypothyroidism or a missed diagnosis of hyperthyroidism.
+This occurs in many species and may lead to false diagnoses of [[hypothyroidism]] or a missed diagnosis of [[hyperthyroidism]].
 <u>'''In horses'''</u>, many factors influence the level of T3 and T4:
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 {{Template:Learning
-|flashcards = [[Thyroid_Gland_Flash_Cards_- Anatomy & Physiology|Thyroid Gland]]
+|flashcards = [[Thyroid_Gland_Flash_Cards_- Anatomy & Physiology|Thyroid Gland]]<br>[[Equine Internal Medicine Q&A 21]]
 |powerpoints = [[Endocrine Histology resource|Histology of the Endocrine system]]
 }}
-[[Category:To Do - Review]]
 {{review}}
 [[Category:Endocrine System - Anatomy & Physiology]]
 [[Category:A&P Done]]

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 :[[Reproductive System Overview - Anatomy & Physiology|'''Reproductive system''']] is affected by  reduced levels of thyroid hormone causing irregular cycling and decreased libido.
 :Finally, in the [[Alimentary System Overview - Anatomy & Physiology|'''alimentary system''']], thyroid hormone increases appetite and feed intake, increases secretion of [[Pancreas - Anatomy & Physiology|pancreatic]] enzymes and increases motility.
 ==Problems associated with the Thyroid Gland==

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 Problems with the thyroid gland include enlargement, or [[Goitre|Goitre]] and also the effects of increased level of hormones in [[Hyperthyroidism|Hyperthyroidism]] or decreased levels of hormones in [[Hypothyroidism|Hypothyroidism]].
-==Test yourself with the Thyroid Gland Flashcards==
+{{Template:Learning
+|flashcards = [[Thyroid_Gland_Flash_Cards_- Anatomy & Physiology|Thyroid Gland]]
-[[Thyroid_Gland_Flash_Cards_- Anatomy & Physiology|Thyroid Gland Flashcards]]
+|powerpoints = [[Endocrine Histology resource|Histology of the Endocrine system]]

@@ Line 1: / Line 1: @@
 ==Introduction==
 The thyroid gland lies in the neck, in front of the upper part of the trachea.  Two types of hormones are produced, which are the iodine containing hormones; '''tri-iodothyronine'''(T3) and '''thyroxine''' (T4). Thyroid hormones regulate the basal metabolic rate and are important in the regulation of growth of tissues, particularly nervous tissue. Release stimulated by TSH from the pituitary. The second type of hormone produced from the thyroid gland is '''[[calcitonin]]''', which regulates blood calcium levels along with parathyroid hormone and acts to reduce blood calcium by inhibiting its removal from bone.
 == Embryological Origin ==
 The thyroid gland is a downgrowth from the pharyngeal endoderm of the developing [[Tongue - Anatomy & Physiology|tongue]]. The calcitonin producing cells are different and are derived from the fourth branchial pouch.
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 ===Ultrastructure and Histology===
 The gland consists of varying sized follicles, which are bounded by a single layer of cuboidal epithelial cells ('''follicular cells'''} and a basement membrane, surrounding a central lumen filled with a homogenous protein rich colloid (thyrogloblin). The apical surface of the cell membranes is covered with numerous micovilli to increase surface area. The follicular cells are connected by tight junctions, and have a dense capillary network. The colloid is a store of thyroid hormones prior to secretion.  The thyroid gland is the only endocrine gland to store its hormone in large quantities. In the active gland colloid is diminished and epithelial cells are tall and columnar.

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 == Embryological Origin ==
-[[Image:Thyroid Gland Low Power.jpg|right|thumb|300px|©RVC 2008]]
+[[Image:Thyroid Gland Low Power.jpg|right|thumb|200px|©RVC 2008]]
-The thyroid gland is a downgrowth from the pharyngeal endoderm of the developing [[Tongue - Anatomy & Physiology|tongue]].
+The thyroid gland is a downgrowth from the pharyngeal endoderm of the developing [[Tongue - Anatomy & Physiology|tongue]]. The calcitonin producing cells are different and are derived from the fourth branchial pouch.
 ==Anatomy==
@@ Line 13: / Line 16: @@
 ===Ultrastructure and Histology===
-[[Image:Thyroid Gland Labelled.jpg|right|thumb|300px|'''Normal Thyroid Gland. ©RVC 2008]]
+[[Image:Thyroid Gland Labelled.jpg|right|thumb|200px|'''Normal Thyroid Gland. ©RVC 2008]]
 <br>
-The gland consists of varying sized follicles. These are a single layer of cuboidal epithelial cells: '''follicular cells''' surrounding a central lumen filled with a protein rich colloid (thyrogloblin). The apical surface of the cell membranes is covered with numerous micovilli to increase surface area. The follicular cells are connected by tight junctions, and have a dense capillary network.
+The gland consists of varying sized follicles, which are bounded by a single layer of cuboidal epithelial cells ('''follicular cells'''} and a basement membrane, surrounding a central lumen filled with a homogenous protein rich colloid (thyrogloblin). The apical surface of the cell membranes is covered with numerous micovilli to increase surface area. The follicular cells are connected by tight junctions, and have a dense capillary network. The colloid is a store of thyroid hormones prior to secretion.  The thyroid gland is the only endocrine gland to store its hormone in large quantities. In the active gland colloid is diminished and epithelial cells are tall and columnar.
-Within the connective tissue close to the follicles are '''C-cells''' alternatively known as '''parafollicular cells'''. These secrete ''[[calcitonin]]'', a hormone which acts to lower plasma Ca2+ levels.
+Within the connective tissue close to the follicles are '''C-cells''' alternatively known as '''parafollicular cells'''. They are found in clusters in the interfollicular space and are also known as '''clear''' cells as their cytoplasm doesn't stain with H and E. They secrete ''[[calcitonin]]'', a hormone which acts to lower plasma Ca2+ levels.
 <center><gallery>
 Image:Thyroid Gland Low Power.jpg|<p>''' Thyroid Gland Low Power 1'''</P><sup>©RVC 2008</sup>
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 ==Problems associated with the Thyroid Gland==
 Problems with the thyroid gland include enlargement, or [[Goitre|Goitre]] and also the effects of increased level of hormones in [[Hyperthyroidism|Hyperthyroidism]] or decreased levels of hormones in [[Hypothyroidism|Hypothyroidism]].
 ==Test yourself with the Thyroid Gland Flashcards==
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 [[Category:Endocrine System - Anatomy & Physiology]]
-[[Category:To Do - Review]]
+[[Category:A&P Done]]