Flashcards in BIOL 0800 Reading- Chapter 11 Deck (162)
What are hormones?
Chemical messengers that enter the blood, which carries them, from their site of secretion to the cells upon which they act
What is the difference between exocrine and endocrine?
Exocrine glands secret products into ducts to exit the body; whereas endocrine glands are ductless and release their secretory products into the interstitial fluid to diffuse into the blood
What are amine hormones?
Derivatives of the amino acid tyrosine
What are the two classes of hormones encompassed by "amine hormones?"
Thyroid hormones and catecholamines
What are the three catecholamines?
Epinephrine, norepinephrine, and dopamine
What are the two parts of the adrenal gland?
Inner adrenal medulla and outer adrenal cortex
What does the adrenal medulla secret more of, epinephrine or norepinephrine?
Where is dopamine synthesized?
In thy hypothalamus, and released by a portal system to inhibit pituitary gland activity
What are prohormones?
The precursor to peptide hormones, which are cleaved from preprohormone by proteolytic enzymes in the RER, to be packaged in the Golgi to yield the active peptide hormones
Does a single prohormone create one kind of peptide hormone?
Nope, can create a whole bunch that are all released together
What are the three classes of hormones?
Amine hormones, peptide hormones, and steroid hormones
What are steroid hormones?
Primarily produced in the adrenal cortex and gonads
What is the general process of steroid hormones synthesis?
Anterior pituitary gland hormone binds to receptors in adrenal cortex/gonads, which are linked to G proteins for cAMP production, activating protein kinase A to facilitate the process through phosphorylation
What is the precursor to all steroid hormones?
How is cholesterol introduced into and used by cells?
Enters as LDLs, which centers cells by receptor-mediated endocytosis and is stored in a liquid droplet until released by the enzyme cholesterol esterase, activated by a protein kinase; then carried to the mitochondria and processed into steroid hormones by cytochrome P450s
What are cytochrome P450s?
Attach hydroxyl groups to carbon atoms and cleave carbon-carbon bonds, to modify cholesterol into steroid hormones
What happens to steroid hormones after synthesis? Where are they stored?
Diffuse across plasma membrane into interstitial fluid and into circulation; not highly soluble in the blood, so primarily transported in plasma bound to carrier proteins like albumin
What are the five major hormones secreted by the adrenal cortex?
Aldosterone, cortisol, corticosterone, DHEA, and androstenedione
What is aldosterone?
A mineralocorticoid, since it affects kidneys' mineral balances (potassium, sodium, hydrogen)
What hormone controls aldosterone production?
What steroid hormones are glucocorticoids?
Cortisol and corticosterone
What steroid hormone is a mineralcorticoid?
What are cortisol and corticosterone?
Glucocorticoids because they affect glucose metabolism
What steroid hormones are androgens?
DHEA and androstenedione
What are DHEA and androstenedione?
Androgens, which includes testosterone
What are the three layers of the adrenal cortex?
Zona glomerulosa, zona fasciculata, and zona reticularis
What is the zona glomerulosa?
Outer layer of the adrenal cortex; only synthesizes/secretes aldosterone; coverts corticosterone to aldosterone, but do NOT code for genes that form cortisol and androgens
What is the zona fasciculata?
Middle layer of the adrenal cortex; secretes cortisol, primarily
What is the zona reticularis?
Inner layer of the adrenal cortex; secretes primarily androgens