Physiology of Endocrine System & Addison's Disease

Flashcards about the physiology of the endocrine system, focusing on Addison's disease, adrenal glands, and related hormones.

What are the presenting symptoms of the patient in the case study?

Symptoms include depression, nausea, fatigue, weight loss, decreased appetite, abdominal pain, joint pain, skin hyper-pigmentation, and abnormalities in nails and mucous membranes. Lab results show low serum cortisol.

Where are the adrenal glands located and what is their shape?

Two, roughly triangular glands located on the upper pole of each kidney.

What are the two main parts of the adrenal gland?

Cortex (outer) and medulla (inner). They differ structurally, functionally, and embryologically.

What are the three main hormones produced by the adrenal cortex?

Mineralocorticoids (aldosterone), Glucocorticoids (cortisol), and Androgens (DHEA).

What is the target tissue and function of mineralocorticoids (aldosterone)?

Kidneys; promotes sodium and water reabsorption, potassium excretion, and maintains blood volume and pressure.

What is the target tissue and function of glucocorticoids (cortisol)?

Most tissues; stimulates the breakdown of protein and fat to make glucose, suppresses the immune system, and reduces inflammation.

What is the target tissue and function of androgens (DHEA)?

Most tissues; precursors to testosterone, responsible for male secondary sex characteristics and sex drive in both sexes.

What is the target tissue and function of epinephrine?

Most tissues; raises metabolic rate, increases heart and respiration rates, and increases blood glucose levels.

What are the two types of adrenal cortex hypofunction?

Acute insufficiency occurs due to sudden stress or failure of ACTH secretion. Chronic insufficiency occurs in Addison's disease.

What are some clinical features of adrenal cortex hypofunction?

Muscular weakness, vomiting, anorexia, GI disturbance, low blood pressure.

Why does muscular weakness occur in adrenal cortex hypofunction?

Loss of sodium chloride and defective power of glycogen formation.

Why does pigmentation of the skin occur in adrenal cortex hypofunction?

Deranged catecholamine production leads to melanin formation, increased MSH or excess ACTH secretion.

What are some common signs and symptoms of Addison's disease?

Anorexia, weakness, fatigue, hyperpigmentation, GI symptoms, hypotension.

What are the main symptoms of Addison's disease?

Bronze pigmentation of skin, changes in hair distribution, hypoglycemia, postural hypotension, GI disturbances, weight loss, weakness.

What are the symptoms of adrenal crisis?

Profound fatigue, dehydration, vascular collapse, renal shutdown, low serum Na, high serum K.

What are some indicators for the diagnosis of primary adrenal insufficiency?

Low DHEAS, high plasma renin, low aldosterone, hyponatremia, hyperkalemia.

What are some indicators for the diagnosis of secondary/tertiary adrenal insufficiency?

Plasma renin and aldosterone generally unaffected, mineralocorticoid deficiency can occur after long-term corticotropin deficiency, other pituitary hormone deficiencies.

What are some examples of medications used as glucocorticoids for the treatment of Addison's disease?

Prednisone, hydrocortisone, dexamethasone

What medication is used as a mineralocorticoid for the treatment of Addison's disease?

Fludrocortisone.

Which androgen can be used as a supplement to improve mood and quality of life in women with Addison's disease?

Dehydroepiandrosterone (DHEA can improve mood and quality of life in women.