Module 3 - The Endocrine System
methods of hormone action
- control of enzymatic reaction rates - control of ion or molecule transport across cell membranes - control of electrical signaling pathways - control of gene expression and protein synthesis
The link between a first messenger and a second messenger in a cell that responds to peptide hormones is usually
G protein
ACTH
The pituitary hormone that controls the release of glucocorticoids from the adrenal cortex
When stimulated by a particular hormone, there is a marked increase in the activity of G proteins in the membrane. The hormone is probably: a steroid. a peptide. testosterone. estrogen. aldosterone.
a peptide
portal system
a specialized region of circulation consisting of two capillary beds directly connected by a set of blood vessels
ACTH target organ
adrenal cortex
primary source of aldosterone
adrenal cortex
primary source of epinephrine
adrenal medulla
The adrenal cortex produces a steroid hormone called ___________ that controls Na+ and K+ homeostasis and another steroid hormone called ___________ that controls blood glucose levels.
aldosterone, cortisol
post-translational modification
alterations to a protein molecule made after translation
derivatives of tyrosine
amino acid derived hormone
half-life
amount of time required to reduce the concentration of a hormone by half
primary source of prolactin
anterior pituitary
trophic hormone
any hormone that controls the secretion of another hormone
hypothalamic hormones
dopamine (prolactin inhibitor), TRH (TSH + prolactin), CRH (ACTH), somatostatin (GH inhibitor), GHRH (GH), GnRH (LH + FSH)
posterior pituitary
extension of neural tissue, stores and releases hypothalamic neurohormones (oxytocin and vasopressin)
Hormones acting through signal transduction pathways elicit a _____________ response compared to hormones that produce genomic effects.
faster
long-loop negative feedback
final hormone from endocrine gland feeds back to hypothalamus and anterior pituitary
LH + FSH (gonadotropins) target organ
gonads
steroid hormone
hormones made from cholesterol
In hormone signaling, the concept of synergism occurs when
hormones working together produce a larger effect than predicted.
prohormone
inactive protein containing one or more copies of a hormone
peptide hormone
lipophobic molecule that interacts with receptors on cell surface
GH target organ
liver
prolactin target organ
mammary gland
Chemical signals released into the blood by neurons are called
neurohormones
primary source of insulin
pancreas
The majority of hormones that function in the body are
peptide hormones
gonadotropin (LH and FSH)
peptide hormones from the the anterior pituitary that acts on the gonads
primary source of melatonin
pineal gland
steroid hormones cannot be...
stored in secretory vesicles
hypothalamic-hypophyseal portal system
takes neurohormones directly from the hypothalamus to the anterior pituitary
TSH target organ
thyroid
primary source of calcitonin
thyroid
short loop negative feedback
trophic hormone feeds back on hypothalamus
anterior pituitary is controlled by
trophic hormones from the hypothalamus
hypothalamic-hypophyseal portal system
trophic hormones reach the anterior pituitary through the portal system; trophic hormones enter the blood via the capillary bed in the hypothalamus, which feeds into portal vessels, which deliver the trophic hormones to the anterior pituitary's cells, which then secrete hormones into the anterior pituitary capillary bed for distribution to body
anterior pituitary
true endocrine gland of epithelial origin