Remainder of chapter 12

Question 1

What is thyroxine (T4) and triiodothyronine(T3) ?

Answer 1

a hormone of the thyroid gland that contains iodine and is a derivative of the amino acid tyrosine. The chemical name for thyroxine is tetraiodothyronine (symbol, T4); it is formed and stored in the thyroid follicles as thyroglobulin, the storage form

Thyroxine acts as a catalyst in the body and influences a great variety of effects, including metabolic rate (oxygen consumption); growth and development; metabolism of carbohydrates, fats, proteins, electrolytes and water; vitamin requirements; reproduction; and resistance to infection.

• Produces a more rapid increase in metabolic rate and has a shorter duration of activity. It’s usually given to treat fat people. Synthetic form of triiodothyronine (T3). Regulates cell growth and differentiation; increases metabolism of lipids, proteins, and carbohydrates; and enhances aerobic mitochondrial function. Also reduces tissue lactic acidosis.

Question 2

Describe the primary metabolic function of each of the following hormones

• Insulin
• glucagon
• Cortisol
• Catecholamines
• T3/T4

Answer 2

• Insulin promotes glucose uptake by adipose tissue and muscle, glucose utilization in muscle cells and macromolecules storage (glycogen edits, lipogenesis)
• Increases blood glucose levels by promoting glycogenesis, gluconeogenesis, lipolysis, and ketogenesis.
• Cortisol increases lipolysis and amino acid mobilization, while decreasing glucose with uptake in certain tissues and enhancing the activity of other counterregulatory hormones
• Catecholamines increases glycogenolysis in muscle and liver and lipolysis in adipose tissue
• Thyoid hormones increase basic metabolic rate and potentiate the activity of other hormones.

Question 3

Thyroid storm is potentially a lethal state of extreme hyperthyroidism in which T3 and T4 levels are above normal limits. What vital sign abnormalities might be expected in a patient with thyroid storm ?

Answer 3

This storm presents with hyperthermia (high temperatures ), tachycardia (fast heart rate)

, hypertension (high blood pressure), and tachypnea (high respiratory rate)

Question 4

What is the preferred fuel for most cells in well fed state ? What is the exception and its preferred fuel ?

Answer 4

• Preferred fuel : Glucose
• Exception : Cardiac muscle. Preferred fuel : Fatty acids

Question 5

What organ consumes the greatest amount of glucose to its percentage of its body mass ?

Answer 5

the brain consumes the greatest amount of glucose depending on its body mass

Question 6

What is Ghrelin ?

Answer 6

Secreted by the stomach in response to signals of an impending meal. Sight, sound, taste, and especially smell act as signals for its release. it increases apetite, and also stimulate secretions of orexin

Question 7

What is Orexin?

Answer 7

Further increases apetite and is also involved in alertness and the sleep wake cycle. Hypoglycemia is also a trigger for orexin release

Question 8

What is Leptin ?

Answer 8

A hormone secreted by fat cells that decreases appetite by suppressing orexin production. Genetic variations in the Leptin molecule and its receptors have been implicated in obesity;