Thyroid disease Flashcards Preview

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Flashcards in Thyroid disease Deck (35)
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1
Q

Where is the thyroid gland situated?

A

In front of the trachea, just below Adam’s apple

2
Q

What are the functional units of the thyroid gland called?

A

Thyroid follicles

3
Q

What are thyroid follicles filled with?

A

Thyroglobulin - acts as a store for iodide

4
Q

What is iodide needed for?

A

Production of thyroid hormone

5
Q

Parafollicular C cells are also found in the thyroid gland. Where are they situated?

A

Between follicles

6
Q

What is the role of parafollicular C cells?

A

Secrete calcitonin - involved in calcium homeostasis

7
Q

Which enzyme converts T4 into T3?

A

Iodothyronine deiodinases

8
Q

Where is DIO1 predominantly found?

A

Liver, kidney, muscles and thyroid gland

9
Q

Where is DIO2 predominantly found?

A

CNS and pituitary thyrotropes

10
Q

Which DIO produces most of the circulating T3?

A

DIO1

11
Q

Which DIO controls intracellular T3 concentration?

A

DIO2

12
Q

Which DIO produces rT3?

A

DIO3

13
Q

How many genes do thyroid hormone receptors have?

A

2 - THRA and THRB found in the nucleus

14
Q

Which receptor do thyroid hormone receptors form a heterdimer with?

A

Retinoid X receptor

15
Q

What are the 5 biological elements of thyroid hormone?

A
Control of metabolic rate
Growth
Foetal development
CV effects
Musculoskeletal effect
16
Q

What are the symptoms of hypothyroidism?

A

Lethargy
Hair loss
Memory loss
Weight gain

17
Q

What are the 3 thyroid function tests that can be performed to diagnose hypothyroidism?

A

Unbound T4
TSH
Thyroid peroxidase antibody

18
Q

In primary hypothyroidism, what happens to unbound T4 and TSH?

A

Increased TSH

Decreased unbound T4

19
Q

What are carbimazole and propylthiouracil used to treat and how do they work?

A

Hyperthyroidism

Work by interfering with thyroid hormones synthesis by inhibiting thyroid peroxidase activity

20
Q

What is used to treat hypothyroidism?

A

Levothyroxine

21
Q

Why may B-blockers need to be given TDS/QDS in hyperthyroidism?

A

Because metabolism is increased

22
Q

What is B-blockers place in therapy in hyperthyroidism?

A

Adjuvant therapy - rapid relief of symptoms (tachycardia, tremor etc.)

23
Q

Which 3 drugs can cause thyroid disease?

A

Iodine
Amiodarone
Lithium

24
Q

Which thyroid disease can iodine deficiency cause?

A

Hypothyroidism

25
Q

How can amiodarone cause mild hyperthyroidism?

A

Blocks conversion of T4 to T3 therefore increases TSH and T4

26
Q

How can amiodarone cause hypothyroidism?

A

Inhibition of the synthesis and release of T3 and T4

27
Q

How does lithium cause hypothyroidism?

A

Inhibits iodine uptake and prevents T3 and T4 release

28
Q

Which two hormones regulate calcium homeostasis?

A

Calcitronin

Parathyroid hormone

29
Q

What is the main function of calcitonin?

A

Reduce blood calcium concentration

30
Q

How many parathyroid glands do most people have?

A

four - located on posterior surface of thyroid gland

31
Q

What are the two cell types that parathyroid glands have?

A

Chief cells

Oxyphill cells

32
Q

What is the function of parathyroid hormone?

A

Increases blood calcium concentration

33
Q

How does PTH increase blood calcium conc?

A

Indirectly stimulating osteoclasts to release more Ca2+ from bone
Increasing renal calcium reabsorption
Increasing vitamin D production -> stimulates Ca2+ uptake from intestine

34
Q

How does calcitonin reduce blood calcium concentration?

A

Reduces osteoclast activity to reduce bone resorption and allow rapid bone deposition by osteoblasts

35
Q

Name some disease of calcium homeostasis

A
Osteoporosis
Rickets
Primary hyperparathyroidism
Secondary hyperparathyroidism
Paget's disease