WEEK 4: Adrenal Flashcards
Each adrenal gland is made up of which two distinct parts?
Adrenal cortex: outer part of gland which produces hormones that are vital to life.
Adrenal medulla: inner part of gland which produces non-essential hormones. This does not mean that these hormones are not important – it just means that our lives do not depend on them.
Which part of the adrenal gland produces hormones involved in the fight-or-flight response?
The adrenal medulla
Which part of the adrenal gland produces steroid hormones?
The adrenal cortex
The adrenal medulla is comprised of … cells that secrete …, mainly adrenaline and noradrenaline, but also dopamine.
chromaffin
catecholamines
The adrenal cortex comprises about …% of the adrenal gland
80
The adrenal cortex can be subdivided into what three layers?
Zona glomerulosa
Zona fasciculata
Zona reticularis
Gonadal steroids can be subdivided into what three sections?
progestogens, oestrogens, and androgens.
Steroid hormones can be grouped into what three families with structural and biological similarities?
Gonadal or sex steroids, glucocorticoids and mineralocorticoids
What is the most important mineralocorticoid?
aldosterone
Mineralocorticoids affect … or … concentrations
mineral or electrolyte concentrations.
What is the precursor of all steroid hormones?
Cholesterol
How can cholesterol be synthesised within cells? (adrenal or gonads)
- from acetate
- from Low Density Lipoprotein (LDL) uptake from blood, via LDL receptor-mediated endocytosis.
What is the intermediate precursor between cholesterol and steroid hormones.
pregnenolone (NOT a hormone)
The highest level of the cholesterol side-chain cleavage system is found in the ……
adrenal cortex, the ovaries and testes.
Name the the major steroid hormone producing glands in the body
the adrenal cortex, the ovaries and testes.
… is the rate limiting enzyme in all steroid hormone production.
Cytochrome P-450scc
T or F
androgens can be converted into oestrogens.
T
After cholesterol is converted to progestogens, what are the progestogens then converted into?
either androgens or glucocorticoids.
Aldosterone is only produced in the zona …
glomerulosa.
T or F
Cortisol can bind strongly to mineralocorticoid receptors.
F
weakly
Why is aldosterone only produced in the zona glomerulosa?
Cells in this layer express the enzyme aldosterone synthase - which converts corticosterone to aldosterone.
T or F
corticosterone, cortisol and aldosterone differ only slightly in structure
T
The main steroid hormones secreted by the adrenal cortex are:
Aldosterone, cortisol, corticosterone, DHEA and androstendione.
T or F
Mineralocorticoids and glucocorticoids are exclusively secreted by the adrenal cortex
T
What layers of the adrenal cortex produce mineralocorticoids and glucocorticoids?
They are produced by the zona fasciculata and zona reticularis layers.
Aldosterone is formed from …, … and …
cholesterol, progesterone and corticosterone
What is the most common glucocorticoid in humans?
Cortisol
The sex steroids include
a) Glucocorticoids
b) Androgens
c) Oestrogens
b
The HPA axis includes a group of hormone-secreting glands from the … and … systems.
nervous and endocrine
What glands are part of the HPA axis?
The hypothalamus, pituitary, and adrenal glands.
What is the primary function of the HPA?
To regulate the stress response.
The … and … act together to regulate the adrenal cortex.
hypothalamus and anterior pituitary
The … and … act together to regulate the adrenal cortex.
hypothalamus and anterior pituitary
When ACTH circulates to the adrenal gland it acts to …
- Increase hormone synthesis and secretion by the adrenal cortex.
- Increase the size of the adrenal gland.
What is the main hormone that ACTH stimulates from the adrenal gland?
cortisol
T or F
ACTH has little or no effect on aldosterone secretion.
T