Chapter 7 - Thyroid

Question 1

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

Answer 1

Chemicals used in everyday products

Question 2

What overlying general concept is largely controlled by the thyroid?

Answer 2

Metabolism (Basal metabolic rate)

Question 3

What does the thyroid regulate?

Answer 3

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

Question 4

What does the thyroid control in children?

Answer 4

Growth, intellect, somatostatin

Question 5

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

Answer 5

Amine hormones derived from tyrosine

Question 6

What kind of cells make up the thyroid gland?

Answer 6

Follicle cells

Question 7

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

Answer 7

Basal membrane

Question 8

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

Answer 8

Sodium-iodide symporter

Question 9

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

Answer 9

Sodium-iodide symporter

Question 10

What is iodide trapping of the thyroid?

Answer 10

Process of concentrating the iodide

Question 11

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

Answer 11

TSH from the anterior pituitary gland

Question 12

What enzymes promote the oxidation of iodine?

Answer 12

Peroxidase and hydrogen peroxide

Question 13

Oxidized iodides join with what substance in the thyroid?

Answer 13

Thyroglobulin

Question 14

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

Answer 14

Tyrosine

Question 15

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

Answer 15

Thyroxine (T4) and triiodothyronine (T3)

Question 16

Thyroxine and triiodothyronine are cleaved from what substance?

Answer 16

Thyroglobulin

Question 17

When are thyroxine and triiodothyronine cleaved from thyroglobulin?

Answer 17

When stimulated by TSH from the pituitary gland

Question 18

How does the cleaving occur in the thyroid tissue?

Answer 18

Pinocytosis by the enlargement of follicle cells and their pseudopod formation

Question 19

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

Answer 19

Thyroxine (T4)

Question 20

What percentage of thyroxine is deiodinated to form additional triiodothyronine?

Answer 20

50%

Question 21

Do thyroid hormones have a slow or fast onset?

Answer 21

Extremely slow

Question 22

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

Answer 22

Increase in linear height

Question 23

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

Answer 23

Osteoblasts (think increase in linear height)

Question 24

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

Answer 24

Somatotrophin and insulin-like growth factor 1

Question 25

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

Answer 25

Most powerful to increase metabolism | Increase energy

Question 26

What is the secondary function of the thyroid gland?

Answer 26

Stimulates the neuromuscular system

Question 27

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

Answer 27

Increases it to sodium and potassium

Question 28

What effect does the thyroid gland have on neurotransmitters?

Answer 28

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

Question 29

How does the thyroid affect the muscular system?

Answer 29

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

Question 30

What effect does the thyroid have on cardiac muscle?

Answer 30

Stimulate myosin heavy chain alpha and inhibits myosin heavy chain beta

Question 31

How does the thyroid gland affect the cardiovascular system?

Answer 31

Heart rate and stroke volume

Question 32

How does the thyroid stimulate the respiratory system?

Answer 32

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

Question 33

What effect does the thyroid have on blood glucose levels?

Answer 33

``` Increases it: Increases glucagon secretion Stimulates enzymes of CHO catabolism Increases cortisol secretion Excess stimulates enzymes of protein catabolism ```

Question 34

What effect does the thyroid gland have on plasma calcium?

Answer 34

Increase

Question 35

How does the thyroid gland affect blood pressure?

Answer 35

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)

Question 36

What effect does the thyroid gland have on the pancreas?

Answer 36

Stimulation (increases the enzymes of digestion)

Question 37

What hormones are stimulated by the thyroid gland?

Answer 37

Glucagon, secretin, gastrin

Question 38

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

Answer 38

Stimulation (increased secretion of cortisol through corticotropin)

Question 39

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

Answer 39

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

Question 40

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

Answer 40

Stimulates the production of skin, hair, and nails

Question 41

How does the thyroid gland increase the immune response?

Answer 41

Increases numbers of B and T lymphocytes

Question 42

How does the thyroid gland stimulate the reproductive system?

Answer 42

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

Question 43

What effect does decreased thyroxine have on the menstrual flow?

Answer 43

Increased

Question 44

What controls the secretion of thyroid releasing factor?

Answer 44

Hypothalamic factor

Question 45

What controls the secretion of TSH?

Answer 45

Adenohypophysis

Question 46

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

Answer 46

Dopamine

Question 47

What effect does estrogen have on TRF and TSH?

Answer 47

Increase

Question 48

What effect does hCG have on TRF and TSH?

Answer 48

Increase

Question 49

What substances are considered to be antithyroid?

Answer 49

Iodine in excess Lithium Some natural foods

Question 50

What substance stimulates antibodies by way of thyroxine?

Answer 50

Thyroid stimulating immunoglobulin (TSI)

Question 51

What is the antibody that stimulates thyroxine?

Answer 51

Long acting thyroid stimulator (LATS)

Question 52

Excess of what substance can block the iodine?

Answer 52

Fluoride