Flashcards in Endocrine - Adrenal hormones Deck (34)
Name the 3 layers of the cortex of the adrenal medulla from outside to inside
1. zona glomerulosa
2. zona fasciculata
3. zona reticularis
what type (chemical category) of hormones does the cortex and medulla of the adrenal cortex secrete?
The cortex releases steroid hormones and the medulla releases catecholamines
what are the three categories of corticosteroids that the adrenal cortex secrete?
3. sex hormones
aside from the inner layers of the adrenal cortex, what other place produces sex hormones?
in the gonads in much higher abundance.
what stimulated the release of cortisol from the adrenal medulla?
ACTH from the anterior pituitary
Why can't steroid hormones move freely in the blood? What are they bound to?
steroid hormones are hydrophobic and so must be transported by proteins. Cortisol is transported by transcortin and the others by albumin
TRUE or FALSE: Cortisol is essential for life. Why or why not?
TRUE; important direct effects on intermediary metabolism of carbohydrate, protein and lipid
what are the effects of cortisol?
1. hepatic gluconeogenesis (amino acids into carbohydrates)
2. increases breakdown of lipids
3. increases protein breakdown (muscles)
4. increases the amount of glucose available to the brain by inhibiting utilization by other tissues
What does the 'permissive action of cortisol' mean?
This means that there is an amount of cortisol that is required to allow for other processes to occur such as its effect on catecholamines
what effects does cortisol have at pharmacological concentrations that it doesn't have at normal concentrations?
using glucocorticoids for long term use can have several consequences. What are they?
1. loss of bone mass
2. impaired body's defence against infections
3. atrophy of the adrenal (negative feedback on pituitary-adrenal axis)
what negative consequences can occur when taking synthetic glucocorticoids?
1. cause negative feedback on anterior pituitary which causes atrophy of corticotropes because no ACTH is required
2. atrophy of adrenal cortex because of lack of stimulation by ACTH
3. low levels of cortisol, aldosterone and DHEA production
what does aldosterone do?
controls body fluid volume by increasing sodium reabsorption by the kidneys
What stimulates aldosterone secretion?
1. activation of renin-angiotensin system in response to decreased blood pressure , low Na and high plasma K
2. ACTH has only a minor role
What does DHEA stand for?
the adrenal androgens are in what major form?
What role does DHEA (androgen) have in female development?
1. enhancement of pubertal growth spurt
2. maintains secondary sex characteristics
3. libido (sex drive)
4. some conversion by aromatase to estrogen
Why is DHEA not as prominent in males?
testosterone androgen produced by the testes overpowers DHEA which is why in females, it's actions are much more significant
caused by a hyper secreting adrenal tumour made up of aldosterone secreting cells (Conn's syndrome); causes increased Na, decreased K, and hypertension
inappropriately high activity of the renin-angiotensin system
What is cushing's syndrome?
an excessive cortisol secretion
what causes Cushing's syndrome?
1. Excessive CRH and ACTH release (hypoth disorder; pituitary tumor)
2. adrenal tumors secreting cortisol independent of ACTH
3. Ectopic tumors (usually lungs) that secrete ACTH
what are the symptoms of Cushing's syndrome?
2. excess protein breakdown
3. abnormal fat distribution
4. insulin resistance (adrenal diabetes)
5. decreased immune response
6. decreased inflammatory response
what does an excess of androgens do in males and females?
- in adult females, causes male pattern body hair, small breast size, inappropriate masculinization
- in newborn females, pseudohermaphroditism
- prepubertal males --> pseudopuberty
- nothing in adult male because of testosterone
congenital adrenal hyperplasia - genetic deficiency in cortisol synthetic enzymes
TRUE or FALSE: Excess DHEA causes negative feedback on GnRH and LH/FSH release from hypothalamus and anterior pituitary
TRUE; no gametes, pseudohermaphroditism, pseudo puberty
if one adrenal medulla is broken down can this cause adrenocortical insufficiency?
no because there is still another one that can compensate. both must be affected
What is primary adrenocortical insufficiency?
- also knows as addison's disease
- an autoimmune disorder where antibodies attack adrenal cortex and so aldosterone and cortisol are deficient
- cortisol and aldosterone defiency
secondary adrenal insufficiency
hypothalamic or pituitary abnormality resulting in deficient ACTH secretion; only cortisol is deficient because aldosterone secretion does not depend on ACTH stimulation