Adrenal Gland with Management of Disorders Flashcards
What hormones are involved in the HPA axis?
CRH (Corticotropin-Releasing Hormone), ACTH (Adrenocorticotropic Hormone), and cortisol.
Where is cortisol produced, and what are its functions?
Produced in the Zona Fasciculata of the adrenal cortex. Functions include stress response, metabolism regulation, immune suppression, and anti-inflammatory effects.
What are the symptoms of cortisol excess?
Weight gain around the face, shoulders, and upper back; secondary hypertension; muscle weakness; purple stretch marks; and easy bruising.
What is the primary regulator of aldosterone secretion?
The Renin-Angiotensin-Aldosterone System (RAAS), particularly Angiotensin II and potassium levels.
What are the main functions of aldosterone?
Regulation of blood pressure and potassium homeostasis.
How can excess cortisol be diagnosed?
Through urinary free cortisol measurements, midnight salivary cortisol, and serum corticotropin measurements.
What role does ACTH play in the regulation of aldosterone?
ACTH has a minor role as an acute regulator, primarily stimulating cortisol production.
What is the significance of the diurnal rhythm in cortisol secretion?
Cortisol levels typically follow a daily cycle, peaking in the morning and decreasing throughout the day.
What enzyme is critical for the final step of aldosterone biosynthesis?
Aldosterone synthase.
What triggers the release of renin from the juxtaglomerular cells?
A drop in blood pressure.
How does Angiotensin II contribute to blood pressure regulation?
It constricts blood vessels and stimulates aldosterone secretion, leading to sodium and water retention, which increases blood pressure.
What are the three zones of the adrenal cortex and the hormones they produce?
Zona Glomerulosa: Aldosterone
Zona Fasciculata: Cortisol
Zona Reticularis: Androgens
How does the HPA axis respond to stress?
Stress increases the release of CRH from the hypothalamus, which stimulates ACTH release from the pituitary, leading to increased cortisol production from the adrenal cortex.
What is the effect of cortisol on glucose metabolism?
Cortisol increases blood glucose levels by promoting gluconeogenesis and decreasing glucose uptake in tissues.
What are the potential effects of long-term cortisol exposure?
Long-term exposure can lead to conditions such as Cushing’s syndrome, characterized by weight gain, hypertension, osteoporosis, and muscle weakness.
What is the main precursor for all steroid hormones?
Cholesterol
What is the role of 17-hydroxylase in steroid hormone synthesis?
It is involved in the synthesis of cortisol and sex steroids, converting pregnenolone and progesterone into 17-hydroxypregnenolone and 17-hydroxyprogesterone, respectively.
How does the body maintain potassium balance in relation to aldosterone?
Aldosterone promotes potassium excretion in the kidneys, helping maintain potassium balance in the body.
What is the role of ACTH in the adrenal cortex?
ACTH stimulates the production and release of cortisol from the Zona Fasciculata and has a lesser role in the production of aldosterone.
Describe the negative feedback mechanism of the HPA axis.
Increased cortisol levels inhibit the release of CRH from the hypothalamus and ACTH from the pituitary, reducing cortisol production.
Describe the parts of the adrenal gland and the production of hormones
Describe the aldosterone biosynthesis
Describe regulation of aldosterone secretion
identify the likely cause from the results of these dexamethasone test
