Thyroid

Question 1

What is the thyroid regulated by

Answer 1

The hypothalamus and pituitary gland

Question 2

What is the thyroid made up of

Answer 2

Follicles (hollow spheres) filled with colloid (protein rich fluid)

Question 3

What does the colloid of the thyroid do

Answer 3

Is the site of much of the process of making the hormones

Question 4

What do the parafollicular C cells release

Answer 4

Calcitonin

Question 5

What releases the thyroid releasing hormone

Answer 5

The hypothalamus in the brain

Question 6

What does the thyroid releasing hormone do

Answer 6

Bonds to receptors in the pituitary gland causing it to release thyroid stimulating hormone regulating the thyroid

Question 7

What does TSH cause

Answer 7

The follicular cells in the thyroid to synthesise and release T3 and T4
Done through upregulation of genes which code for proteins in the thyroid hormone synthesis pathway

Question 8

How do thyroid hormones travel

Answer 8

In the blood bound to proteins

Question 9

How do thyroid hormones get to their target

Answer 9

Through blood then diffuse into target cells act via intracellular receptors releasing a depressor form certain genes which can be transcribed and translated to protein

Question 10

What are 4 proteins as a result of thyroid hormones effects

Answer 10

Growth and development
Macronutrient metabolism
Basal metabolic rate
Synergy with catecholamines

Question 11

How does parathyroid hormone work

Answer 11

Increasing Ca2+ released from the bones
Decreasing Ca2+ excretion by increasing reabsorption in the kidneys

Question 12

What type of feedback is the hypothalamic pituitary thyroid axis

Answer 12

Negative feedback loop

Question 13

What does high T3 and T4 levels cause

Answer 13

Suppression of TSH production

Question 14

What do high TSH levels cause

Answer 14

Suppression of TRH production

Question 15

What do thyroid hormones require

Answer 15

Iodine to synthesis T3 and T4

Question 16

What does the drug caebimazole do

Answer 16

Helps to interfere with someone who produces too much T3 and T4 hormones

Question 17

What are the most common thyroid hormone in the blood

Answer 17

T4 as when they synthesise in a cell they loose an iodine resulting in turning into T3

Question 18

What do thyroid hormones do in macronutrient metabolism

Answer 18

Increase breakdown of glycogen and formation of glucose
Increase formation of lipids and lipid breakdown to release fatty acids - energy

Question 19

What do thyroid hormones do for the basal metabolic rate

Answer 19

Increase this increasing heat generated by increasing ATPase expression

Question 20

What happens when there is a lack of thyroid hormones in childhood

Answer 20

Potentially result in short stature and mental impairment
Low energy
Over heating
Weight change

Question 21

What can an underactive thyroid (hypothyroidism) result in

Answer 21

Tiredness, lack of energy, weight gain, depression, sensitivity to cold
Caused by immune system attacking thyroid - Hashimoto disease

Question 22

What can an overactive thyroid (hyperthyroidism) result in

Answer 22

Nervousness, anxiety, difficulty sleeping, tiredness, weight loss, sensitivity to heat
Caused by Graves’ disease where antibody is produced that mimics TSH leading to overproduction or caused by medications

Question 23

What cells synthesis T3 and T4

Answer 23

Epithelial cells of the follicles

Question 24

What are 4 affects of the thyroid hormones

Answer 24

Growth and development
Macronutrient metabolism
Basal metabolic rate
Synergy with catecholamines