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Thyroid Gland Flash Cards - Anatomy & Physiology (view source)
Revision as of 16:47, 3 September 2008
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!width="250"|'''Question'''
!width="500"|'''Answer'''
!width="50"|'''Article'''
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|<big>Describe embryological origin of the Thyroid Gland.
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*The thyroid gland is a downgrowth from the pharyngeal endoderm of the developing tongue.
||[[Thyroid Gland - Anatomy & Physiology|Answer article]]
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|<big>Describe the location of the thyroid gland, it's closely associated structures and anatomical landmarks.
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*The thyroid gland is adjacent to the cranial part of the trachea, closely associated with the Parathyroid Glands which may be within or close to the thyroid gland itself.
*Close to the thyroid gland are the ''Sternohyoid'' and ''Sternothyroid'' muscles, the ''recurrent laryngeal'' nerve and the ''carotid sheath''.
||[[Thyroid Gland - Anatomy & Physiology|Answer article]]
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|<big>Describe the blood supply and venous drainage of the Thyroid Gland.
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*Supply = Cranial Thyroid Artery and Caudal Thyroid Artery
*Venous Drainage = Thyroid Vein (leading to Internal Jugular Vein).
||[[Thyroid Gland - Anatomy & Physiology|Answer article]]
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|<big>The Thyroid gland consists of various sized follicles. What is the name of the cells which line the lumen of the follicles, and what is their function?
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* Follicular Cells - these synthesize thyroglobulin in their golgi apparatus. Thyroglobulin is a glycoprotein consisting of 70 linked ''tyrosine'' molecules and is the source of thyroid hormones.
||[[Thyroid Gland - Anatomy & Physiology|Answer article]]
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|<big>Label the following histological section:
[[Image:ThyroidGlandFlashCard1.jpg|left|thumb|250px|©RVC 2008]]
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*A = Connective Tissue Capsule
*B = Thyroid Follicles
*C = Connective Tissue Septum
*D = Blood Vessels in Capsule.
||[[Thyroid Gland - Anatomy & Physiology#Histology Gallery|Answer Article]]
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|<big>Which Letter represents the location of the C-Cells of the Thyroid Gland, and what is their function?
[[Image:ThyroidGlandFlashCard.jpg|left|thumb|250px|©RVC 2008]]
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*A represents the C Cells.
*The C-Cells (aka Parafollicular Cells) produce Calcitonin, a hormone which acts to lower the plasma calcium level.
||[[Thyroid Gland - Anatomy & Physiology#Ultrastructure and Histology|Answer Article]]
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|<big>Define and describe the process of ''Iodide Trapping''.
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*Iodide trapping is the process by which Iodide molecules (I-) are concentrated in the colloid at a level up to 250x greater than the plasma level.
*The Na+/I- symport in the basal membrane of the follicular cells moves the iodine from the plasma, into the cell. From here is is transported into the colloid.
*The follicular cells and the pumps function in response to Thyroid Stimulating Hormone from the Pituitary Gland.
||[[Thyroid Gland - Anatomy & Physiology#Iodine Uptake|Answer Article]]
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|<big>Name the three hormones produced in the thyroid gland and describe how they are transported around the body?
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*Hormones: Triiodothyronine (T3), Thyroxine (T4) and Reverse T3.
*Thyroid hormones are lipid soluble, thus require a binding protein in order to travel in the bloodstream. Thyroid Binding Globulin caries 70-80% of the circulating hormone, with Thyroxine Binding Pre-Albumin, and Albumin carrying the remainder.
||[[Thyroid Gland - Anatomy & Physiology#Transport|Answer article]]
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|<big>What are Hormone A and Hormone B in this schematic diagram of the Hypothalamic - Pituitary - Thyroid Axis:
[[Image:ThyroidGlandFlashCard3.jpg|left|thumb|250px]]
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*Hormone A = TRH - Thyrotropin Releasing Hormone
*Hormone B = TSH - Thyroid Stimulating Hormone (Thyrotropin)
||[[Thyroid Gland - Anatomy & Physiology#Regulation|Answer article]]
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|<big>Decribe the effects that T3 and T4 have on the following systems/physiological mechanisms:
*Musculoskeletal System
*Carbohydrate metabolism
*Fat metabolism
*Basal Metabolic Rate
*Cardiovascular System
*Nervous System
*Alimentary System
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*'''Musculoskeletal system''' - Thyroid hormone promotes bone growth
*'''Carbohydrate metabolism''' - Thyroid hormone stimulates glucose uptake, glycolysis, gluconeogenesis
*'''Fat metabolism''' - Thyroid hormone mobilises lipids from adipose stores. Accelerates oxidation of lipids to produce energy (occurs within mitochondria). Increases size and number of mitochondria.
*'''Basal Metabolic Rate''' (BMR) - Thyroid hormone causes and increase in BMR in all tissues except brain, spleen, gonads. Results in increased heat production, increased oxygen consumption.
*'''Cardiovascular actions''' - Thyroid hormone increases Cardiac output, heart rate and contractility.
*'''Nervous system''' - thyroid hormones are required for development of this system. They also enhance the sympathetic nervous system (by increasing epinephrine receptors).
*'''Alimentary System''' - Thyroid hormone increases appetite and feed intake, increases secretion of pancreatic enzymes and increases motility.
||[[Thyroid Gland - Anatomy & Physiology#Thyroid Hormone Actions|Answer article]]
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