Endocrinology II Flashcards
The water concentration of the body is monitored by
osmoreceptors in the hypothalamus, which
detect the concentration of electrolytes in the extracellular fluid.
polypeptide hormone ADH/vasopressin is produced and released where
The hypothalamus produces it,
then its transported to and released from the posterior pituitary
The principal action of ADH is
to regulate the amount of water excreted by the kidneys by causing direct water reabsorption from the kidney
tubules
ADH mechanism of action more specifically
travels via the bloodstream to the kidneys where it temporarily inserts aquaporins into the kidney tubules thus kidneys become more permeable to water
what results in diabetes insipidus
Chronic underproduction of ADH or a mutation in the ADH receptor
Define diabetes insipidus
a rare condition where you produce a large amount of urine and often feel thirsty
Another hormone responsible for maintaining electrolyte concentrations
aldosterone, a steroid hormone produced by the adrenal cortex
how does aldosterone aid in maintaining proper water balance
by enhancing Na+ reabsorption and K+ secretion from in kidney tubules.
The reabsorption of Na+ also results in the osmotic reabsorption of water, which alters blood volume and blood pressure.
what type of corticosteroid is aldosterone
referred to as a mineralocorticoid, which is a
corticosteroid that affects ion and water balance.
Aldosterone release is stimulated by
a decrease in blood sodium levels,
blood volume, or blood pressure,
or an increase in blood potassium levels.
what is RAAS
renin-angiotensin-aldosterone system
when is RAAS activated
When blood pressure drops
Where is renin produced and released
in the cells of the juxtaglomerular apparatus,
which regulates the functions of the nephrons of
the kidney
What is renin and what does it do
an enzyme, circulates in the blood, reacts with a
plasma protein produced by the liver called angiotensinogen
how is angiotensin I made
When angiotensinogen is cleaved by renin, it produces angiotensin I
what is angiotensin II and what does it do
functions as a hormone, causing the release of aldosterone by the adrenal cortex,
resulting in increased Na+ reabsorption, water retention, and an increase in blood pressure.
in addition to affecting aldosterone, what else does angiotensin II stimulate
in addition to being a potent vasoconstrictor, also causes an increase in ADH and increased thirst, both of which help to raise blood pressure.
what is a natriuretic peptide
circulating peptide hormones of cardiac origin that induce natriuresis, which is the excretion of sodium by the kidneys.
important in the regulation of intravascular blood volume and vascular tone.
what is ANP and where secreted
Atrial natriuretic peptide is secreted by atrial cardiac muscle cells
what is BNP and where secreted
Brain natriuretic peptide is secreted by ventricular cardiac muscle cells
name some natriuretic peptide functions
increase urinary excretion of sodium,
increase GFR,
inhibit Na+ reabsorption in distal tubule and collecting duct,
inhibit secretion of renin, aldosterone and vasopressin, decrease cardiac output,
inhibit sympathetic activity
insulin mechanism of action for lowering plasma GLU concentration
insulin binds to its target cell via insulin receptors,
signal transduction triggers
the cell to incorporate glucose transport proteins into its membrane.
This allows glucose to enter the cell, where it can be used as an energy source.
insulin mechanism of action for lowering plasma GLU concentration
insulin binds to its target cell via insulin receptors,
signal transduction triggers
the cell to incorporate glucose transport proteins into its membrane.
This allows glucose to enter the cells and plasma concent. lowers
diabetes mellitus can be specifically due to what 2 processes
inadequate levels of insulin production by the beta cells of the pancreas,
or by reduced sensitivity of tissue cells to insulin.
calcitonin is from?
the parafollicular or C cells in the thyroid gland
