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Flashcards in 21. Metabolic Rate Control Deck (20):
1

How does the excess growth hormone differ between children & adults?

Children = gigantism
Adults = acromegaly - thick bones, tissues overgrow

2

How does growth hormone deficiency differ between children & adults?

Children = dwarfism
Adults = no obvious disease. But giving them GH increases lean body mass and vigour

3

Where are signals driving growth hormone expression integrated?

Hypothalamus

4

What hormones increase and supress growth hormone secretion from the anterior pituitary gland?

GRH = Increase
Somatostatin = Suppress

5

Growth hormone is secreted in pulses and more is secreted during the day.
True or False?

FALSE
more is secreted at night during sleep.

6

Growth hormone increases blood glucose levels. What are its immediate effects on metabolism?

Liver: ↑ gluconeogenesis
Fat: ↑ lipolysis
Muscles: ↓ glucose uptake
Insulin resistance

7

Identify 4 hormones which affect growth.

1. Growth hormone
2. Insulin
3. Steroids
4. Thyroid hormones

8

T3 has a longer half-life than T4.
True or False?

FALSE
T4 = 8 days
T3 = 1 day (most active form)

9

What is the difference between TSH and TRH?

TRH (thyroid releasing hormone) = produced by hypothalamus to release TSH from anterior pituitary gland
TSH (thyroid stimulating hormone) = induces thyroid hormone production from thyroid gland

10

Which of these is NOT a function of thyroid hormone?
1. Heat generation
2. Decreasing metabolic rate
3. Growth & Development
4. Increasing metabolic rate

2. Decreasing metabolic rate

11

Where is the thyroid found in the body?

Neck, anchored to thyroid cartilage.
Moves when swallowing.

12

What hormone is responsible for nearly all steps in thyroid hormone production?

TSH

13

How is T4 de-iodinated to T3?

2 enzymes:
Type I - found in liver, kidney, thyroid
Type II - found in pituitary, CNS, placenta

14

How does the thyroid hormone increase heat production?

Does metabolic reactions for the fuck of it.
↑ gluconeogenesis / ↑ glycogenolysis
↑ lipogenesis / ↑ lipolysis
↑ proteolysis / ↑ protein synthesis (wastes muscle overall)

15

Thyroid hormone is crucial for brain development and growth.
True or False?

TRUE

16

How can autoimmunity cause hypo & hyperthyroidism?

Antibodies against TSH receptor can activate it and drive excess TH production. (hyperthyroidism)
Antibodies can destroy TSH receptors. (hypothyroidism)

17

What is the main natural glucocorticoid in humans?

Cortisol

18

How is cortisol production induced?

1. Hypothalamus integrates stress signals to release CRH (corticotrophin releasing hormone).
2. CRH stimulates ACTH (adrenocorticotrophin) release from anterior pituitary gland.
3. ACTH stimulates adrenal cortex to produce cortisol.

19

What is the acute metabolic effect of glucocorticoids?

Increases blood glucose levels and targets this to the brain.
1. ↑ glucogenogenesis in liver
2. ↑ lipolysis
3. ↑ muscle breakdown for gluconeogenesis

20

What are glucocorticoids used for clinically?

Immunosuppression - reduces inflammation