Chapter 7 - Thyroid Flashcards Preview

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Flashcards in Chapter 7 - Thyroid Deck (52)
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1
Q

What is thought to be the reason for the increase in thyroid conditions nationwide?

A

Chemicals used in everyday products

2
Q

What overlying general concept is largely controlled by the thyroid?

A

Metabolism (Basal metabolic rate)

3
Q

What does the thyroid regulate?

A

Digestion, oxygen, mobilization of fat from storage cells, body temperature

4
Q

What does the thyroid control in children?

A

Growth, intellect, somatostatin

5
Q

Thyroid hormones are what kind of hormones and are derived from what amino acid?

A

Amine hormones derived from tyrosine

6
Q

What kind of cells make up the thyroid gland?

A

Follicle cells

7
Q

What part of the thyroid cell pumps iodide into the cell?

A

Basal membrane

8
Q

What is used to transport one iodide for every two sodium ions in the thyroid?

A

Sodium-iodide symporter

9
Q

What is the first stage of the iodide process of the thyroid gland?

A

Sodium-iodide symporter

10
Q

What is iodide trapping of the thyroid?

A

Process of concentrating the iodide

11
Q

What influences the rate at which iodide is trapped by the thyroid gland?

A

TSH from the anterior pituitary gland

12
Q

What enzymes promote the oxidation of iodine?

A

Peroxidase and hydrogen peroxide

13
Q

Oxidized iodides join with what substance in the thyroid?

A

Thyroglobulin

14
Q

Oxidized iodine binds directly with what substance to produce monoiodotryosine and diiosotyrosine?

A

Tyrosine

15
Q

What is the major hormonal product of the coupling reaction during the iodine process of the thyroid gland?

A

Thyroxine (T4) and triiodothyronine (T3)

16
Q

Thyroxine and triiodothyronine are cleaved from what substance?

A

Thyroglobulin

17
Q

When are thyroxine and triiodothyronine cleaved from thyroglobulin?

A

When stimulated by TSH from the pituitary gland

18
Q

How does the cleaving occur in the thyroid tissue?

A

Pinocytosis by the enlargement of follicle cells and their pseudopod formation

19
Q

What thyroid hormone makes up the majority that is released into the bloodstream?

A

Thyroxine (T4)

20
Q

What percentage of thyroxine is deiodinated to form additional triiodothyronine?

A

50%

21
Q

Do thyroid hormones have a slow or fast onset?

A

Extremely slow

22
Q

What is the primary function of the thyroid gland in children?

A

Increase in linear height

23
Q

The thyroid gland stimulates the activity of what bone cells in children?

A

Osteoblasts (think increase in linear height)

24
Q

The thyroid gland stimulates the secretion of what “growth” hormones?

A

Somatotrophin and insulin-like growth factor 1

25
Q

What is the primary means of the thyroid gland in adults and children?

A

Most powerful to increase metabolism

Increase energy

26
Q

What is the secondary function of the thyroid gland?

A

Stimulates the neuromuscular system

27
Q

How does the thyroid gland affect the cell membrane permeability of certain ions?

A

Increases it to sodium and potassium

28
Q

What effect does the thyroid gland have on neurotransmitters?

A

Increased synthesis and increased numbers of receptors for them (also decreases enzymes that catabolize neurotransmitters)

29
Q

How does the thyroid affect the muscular system?

A

Stimulate the enzymes of protein anabolism
Release calcium along T-tubules of smooth and skeletal muscle
Control contractile velocity of cardiac muscle

30
Q

What effect does the thyroid have on cardiac muscle?

A

Stimulate myosin heavy chain alpha and inhibits myosin heavy chain beta

31
Q

How does the thyroid gland affect the cardiovascular system?

A

Heart rate and stroke volume

32
Q

How does the thyroid stimulate the respiratory system?

A

Stimulates the enzymes of catabolism which releases CO2, release of calcium at T-tubules (flucuating thyroxine can lead to difficulty breathing)

33
Q

What effect does the thyroid have on blood glucose levels?

A
Increases it:
Increases glucagon secretion
Stimulates enzymes of CHO catabolism
Increases cortisol secretion
Excess stimulates enzymes of protein catabolism
34
Q

What effect does the thyroid gland have on plasma calcium?

A

Increase

35
Q

How does the thyroid gland affect blood pressure?

A

Can become high due to increases in heart rate and/or increase in stroke volume
Can become low due to catabolism of cardiac muscle (high thyroxine)

36
Q

What effect does the thyroid gland have on the pancreas?

A

Stimulation (increases the enzymes of digestion)

37
Q

What hormones are stimulated by the thyroid gland?

A

Glucagon, secretin, gastrin

38
Q

What effect does the thyroid gland have on the adrenal gland (overall endocrine glands too)?

A

Stimulation (increased secretion of cortisol through corticotropin)

39
Q

What is stimulated by the thyroid gland to stimulate tissue oxygenation?

A

Increase secretion of erythropoietin (2,3 DPG enzyme that frees oxygen from RBCs)

40
Q

What effect does the thyroid gland have on the integumentary system?

A

Stimulates the production of skin, hair, and nails

41
Q

How does the thyroid gland increase the immune response?

A

Increases numbers of B and T lymphocytes

42
Q

How does the thyroid gland stimulate the reproductive system?

A

Increased or decreased production of sex hormones (fertility vs sterility)
Production of gametes

43
Q

What effect does decreased thyroxine have on the menstrual flow?

A

Increased

44
Q

What controls the secretion of thyroid releasing factor?

A

Hypothalamic factor

45
Q

What controls the secretion of TSH?

A

Adenohypophysis

46
Q

What neurotransmitter can act as a hormone that decreases TSH and thyroxine?

A

Dopamine

47
Q

What effect does estrogen have on TRF and TSH?

A

Increase

48
Q

What effect does hCG have on TRF and TSH?

A

Increase

49
Q

What substances are considered to be antithyroid?

A

Iodine in excess
Lithium
Some natural foods

50
Q

What substance stimulates antibodies by way of thyroxine?

A

Thyroid stimulating immunoglobulin (TSI)

51
Q

What is the antibody that stimulates thyroxine?

A

Long acting thyroid stimulator (LATS)

52
Q

Excess of what substance can block the iodine?

A

Fluoride