Thyroid Flashcards

1
Q

Thyroid tissues consist of

A

Sac like structures called thyroid follicles

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2
Q

How are the follicular cells arranged

A

In circular pattern

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3
Q

Characteristics of the follicle cells (2)

A

Single layer of epithelium

Synthesize the thyroid hormone

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4
Q

Follicles are filled with what

A

Colloid

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5
Q

What is the colloid (2)

A

Viscous protein rich liquid

Main storage form of the thyroid hormone

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6
Q

C cells or parafollicular cells are located where

A

outside follicle

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7
Q

C cell secrete

A

Calcitonin

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8
Q

Calcitonin is

A

A hormone that regulate calcium metabolism

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9
Q

Molecules important for the production of thyroid hormones (2)

A

Tyrosine

Iodine

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10
Q

Tyrosine is a part of a large protein called

A

Thyroglobulin

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11
Q

Where does iodine come from

A

From the diet

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12
Q

Iodine is converted to

Where

A

Iodide

In the intestinal tract and transported to thyroid

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13
Q

T or F

Iodide concentration is higher in the outside of the cell

A

False

Concentration is 25-200x higher IC

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14
Q

How do follicle cell trap iodide

A

With the Na/I transporter

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15
Q

The 1st step in the production is

A

Oxidation of iodide into iodine

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16
Q

Who oxidizes iodide into iodine

A

Thyroid peroxidase (TPO) located in the apical membrane

17
Q

Binding of the iodine with the thyroglobulin molecule is called

And happens where

A

Organification of the thyroglobulin

In colloid or outside of cell

18
Q

Tyrosyl ring can accommodate 2 iodine molecules which are

A

MIT monoiodotyrosine

DIT diiodotyrosine

19
Q

MIT is

A

One molecule of iodine

20
Q

DIT is

A

Two molecules of iodine

21
Q

TPO catalyzes the fusion of

A

2 of these iodinated tyrosines

22
Q

1 DIT + 1DIT=

A

4 iodine molecules

23
Q

1MIT + 1 DIT=

A

3 iodine molecules

24
Q

3 iodine-tyrosine molecules are called

A

T3 OR TRIIODOTHYRONINE

25
4 iodine-tyrosine molecules are called
T4 OR THYROXINE
26
What is the major hormone produced by follicle cells
T4
27
Thyroid hormones will secreted after stimulation by
TSH
28
TSH is released by
Adenohypophysis
29
Who releases TRH
Hypothalamus
30
How are thyroid hormones are transported
In plasma attached proteins such as Thyroxine binding protein (TBG) and albumin
31
TGB and albumin are produced by
Liver
32
Free T4 enters and is converted into T3 by
Iodothyronine deiodinases in cytosol
33
What is the primary factor for the control of metabolism
Thyroid hormones
34
Actions of thyroid hormones (7)
``` Increase the number of mitochondrial prot and activity Increase basal metabolic rate of cells Stimulate carbohydrate metabolism Fat metabolism Influence growth and development Increase blood flow and cardiac output Increase heart rate ```
35
T or F Weight gain in hypo Weight loss in hyper
True
36
T or F | Plasma and liver fat are decreased under thyroid stimulation
True