Lecture 3-Renal Concentrating Mechanisms And Urine Formation Flashcards
(113 cards)
___ is a protein enzyme released by the kidneys when BP is too low
Renin
The ___ apparatus is the site of renin synthesis
Juxtaglomerular apparatus
The JGA consists of (4) components: 1) modified smooth muscle cells in ___ arteriole; 2) modified smooth muscle cells in the ___ arteriole; 3) extraglomerular ___ cells; 4) ___ cells in the distal tubule
1) modified smooth muscle cells in the afferent arteriole; 2) modified smooth muscle cells in the efferent arteriole; 3) extraglomerular mesangial cells; 4) macula densa cells in the distal tubule
Glomerulus blood supply in = ___ arterioles; glomerulus blood supply out = ___ arterioles
In = afferent; out = efferent
Renin Angiotensin Pathway—renin causes ___ to be cleaved to ___; ___ converted to ___ in the lung by ___ (inhibited by ___); ___ is the most potent vasoconstrictor known
Renin causes angiotensinogen to be cleaved to angiotensin I; angiotensin I converted to angiotensin II in the lung by angiotensin converting enzyme (inhibited by ACE inhibitors); angiotensin II is the most potent vasoconstrictor known
Actions of angiotensin II—vaso___ and ___ (increased/decreased) blood pressure; increased ___ synthesis and release; increased ___ release; increased thirst; feedback inhibition of ___ release
Vasoconstriction and increased blood pressure; increased aldosterone synthesis and release; increased ADH (antidiuretic hormone) release; increased thirst; feedback inhibition of renin release
Although angiotensin II constricts both afferent and efferent arterioles, it releases ___, which act to maintain GFR in spite of its constrictive effects
Prostaglandins
Angiotensin II acts on the ___ gland to stimulate the release of aldosterone
Adrenal
Aldosterone acts on the kidneys to stimulate reabsorption of ___ and ___
Salt and water
Aldosterone is a steroid hormone synthesized in the zona ___ of the adrenal cortex
Zona glomerulosa
Stimulation for aldosterone release and synthesis include: ___ (increased/decreased) K+ levels in the ECF; angiotensin ___; ___ (increased/decreased) Na+ levels
increased K+ levels in the ECF; angiotensin II; decreased Na+ levels
Aldosterone acts on the ___ tubule and collecting ducts to cause K+ and H+ ___ in exchange for ___; net effect is to get rid of ___ and ___
Aldosterone acts on the distal tubule and collecting ducts to cause K+ and H+ secretion (removal) in exchange for Na+; net effect is to get rid of K+ and H+
Aldosterone helps to control blood pressure by holding onto ___ and losing ___ from the blood
Holding onto salt and losing potassium
___ is a hormone antagonistic to the angiotensin pathway
ANP
ANP ___ (increases/decreases) blood volume and pressure by: ___ (increasing/decreasing) the glomerular filtration rate; ___ (increasing/decreasing) reabsorption of Na+ by nephrons; inhibiting the release of ___, ___, and ___
ANP decreases blood volume and pressure by: increasing the glomerular filtration rate; decreasing reabsorption of Na+ by nephrons; inhibiting the release of renin, aldosterone, and ADH
Clinical relevance of aldosterone—___ syndrome
Conn’s
Conn’s syndrome = ___aldosteronism
Hyper
Conn’s syndrome—aldosterone secreting tumor causes ___tension, ___natremia, ___kalemia; eventually, the increased Na+ load exceeds the distal tubule and collecting duct ability to ___ Na+; however, ___ excretion continues and this can be fatal (___kalemia will cause ___polarization of nerve and muscle cells)
Hypertension, hypernatremia, hypokalemia; eventually, the increased Na+ load exceeds the distal tubule and collecting duct ability to reabsorb Na+; however, K+ excretion continues and this can be fatal (hypokalemia will cause hyperpolarization of nerve and muscle cells)
Renal concentrating and diluting mechanisms—___ hormone; ___ peptide; the ___ multiplier; the role of ___
Antidiuretic hormone (ADH); atrial natriuretic peptide (ANP); the countercurrent multiplier; the role of urea
The kidneys can excrete a large volume of dilute urine or a small volume of concentrated urine without major changes in rates of excretion of solutes such as sodium and potassium—T/F?
True
The kidney is able to excrete excess water by forming a ___ (dilute/concentrated) urine
Dilute
The kidney conserves water by ___ (diluting/concentrating) the urine
Concentrating
Obligatory urine volume is dictated by the maximum ___ ability of the kidney
Maximum concentrating ability of the kidney
Obligatory urine volume = ___ L/Day
0.5 L/Day
Example: A normal 70 kg human must excrete 600 mOsm of solute each day; assuming a maximum urine concentrating ability of 1200 mOsm/L. (600 mOsm/Day) / (1200 mOsm/L) = 0.5 L/Day