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Flashcards in Thyroid Hormonal System Deck (50)
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1

Functional unit of the parathyroid gland

Parathyroid Cells (Chief Cells)

2

Congenital hypothyroidism occurs in _________.

Congenital hypothyroidism occurs in foals.

3

Percursors of thyroid hormone synthesis

Tyrosine Amino Acids

Iodide

4

_____________ is synthesized and secreted by parathyroid glands and is stimulated by decreased [calcium]

Parathyroid Hormone (PTH) is synthesized and secreted by parathyroid glands and is stimulated by decreased [calcium]

5

The primary clearance organs for thyroid hormone are

liver and kidney

6

_____________ is characterized by decreased thyroid horomone and thus decreased metabolic rate.

Hypothyroidism is characterized by decreased thyroid horomone and thus decreased metabolic rate.

7

When T3 binds _________ receptors it activates oxidative phosphorylation and ATP synthesis

When T3 binds mitochondrial receptors it activates oxidative phosphorylation and ATP synthesis

8

______________ blood samples are taken before and after administration of TSH.

TSH Stimulation Test blood samples are taken before and after administration of TSH.

________________

Expect to see increased T4 after administration

Was Gold Standard at one time

9

____________: located between thyroid follicles, produce calcitonin.

Parafollicular Cells (C Cells): located between thyroid follicles, produce calcitonin.

10

Cold temperatures (increases/decreases) [T3]

Cold temperatures (increases/decreases) [T3]

11

Etiology of Hypothyroidism

Lymphatic thyroiditis (autoimmune)

Idiopathic atrophy

12

Control of Thyroid Hormone homeostasis is maintained by the ____________.

Control of Thyroid Hormone homeostasis is maintained by the Hypothalamic - Pituitary - Thyroid- Axis.

13

___________ is synthesized and secreted by parafollicular cells and is stimulated by increased [calcium]

Calcitonin is synthesized and secreted by parafollicular cells and is stimulated by increased [calcium]

14

Calcitonin effects on target tissues

@ Bone - inhibits osteoclast activiyt

@ Kidney - inhibits reabsorption of calcium

@ GI - inhibits absorption of calcium

15

Increased [T3] and [T4] (increases/decreases) the release of TRH and TSH

Increased [T3] and [T4] (increases/decreases) the release of TRH and TSH

16

__________: epithelial cells in spherical arrangement that produce thyroid hormones.

Thyroid Follicles: epithelial cells in spherical arrangement that produce thyroid hormones.

17

____________ disease in which excessive amounts of PTH produced leading to increased blood [calcium]

Hyperparathyroidism disease in which excessive amounts of PTH produced leading to increased blood [calcium]

18

_____________ binds to anterior pituitary and signals the release of TSH

Thyroid Releasing Hormone (TRH) binds to anterior pituitary and signals the release of TSH

19

High carbohydrate diet (increases/decreases) [T3] causing an (increased/decreased) metabolic rate.

High carbohydrate diet (increases/decreases) [T3] causing an (increased/decreased) metabolic rate.

20

___________ are provided by thyroglobulin and secreted into the colloid.

Tyrosine Amino Acids are provided by thyroglobulin and secreted into the colloid.

21

____________: densely arranged near capillaries and produce parathyroid hormone (PTH)

Parathyroid (Chief) Cells: densely arranged near capillaries and produce parathyroid hormone (PTH)

22

__________ is the most common feline endocrine disorder.

Hyperthyroidism is the most common feline endocrine disorder.

23

Diagnosis of Hyperthyroidism

tT4

fT4

tT3 or fT3

TSH Stimulation Test

T3 Suppression Test

24

______________ test for hyperthyroidism where T3 is administered to inhibit the release of TSH and decrease T4 secretion.

T3 Suppression Test test for hyperthyroidism where T3 is administered to inhibit the release of TSH and decrease T4 secretion.

25

Thyroid hormones are _______ soluble.

Thyroid hormones are fat soluble.

 

___________________

Must be bound to protein in order to circulate

26

Explain the process of secretion of thyroid horomones

Epithelial cells ingest colloid by endocytosis

Endosomes fuse whith lysosomes to liberate thyroglobulin

Free thyroid hormones diffuse out

 

27

Explain thyroid hormone mechanism of action

Free T3 and T4 taken up by target cell

In cytoplasm T3/T4 bound to transport proteins

T4 → T3 by deiodinase

T3 binds mitochondrial or nuclear receptors

28

_____________ : enzyme that brings precursor molecules together

Thyroxoid Peroxidase (TPO) : enzyme that brings precursor molecules together

29

_____________ disease in which C cell production of calcitonin may be impaired leading to increased blood [calcium]

Thyroid Parafollicular Cell Dysfunction disease in which C cell production of calcitonin may be impaired leading to increased blood [calcium]

30

________ is the bioactive thyroid hormone.

T3 is the bioactive thyroid hormone.