Final Exam Flashcards
(78 cards)
What is extracellular fluid volume dependent on?
Intake and output of fluid and sodium
If the kidneys cannot maintain homeostatic balance of sodium, what 3 systemic adjustments can be made to help?
- Chg blood pressure
- Chg circulating hormones
- Chg in sympathetic nervous system
If the kidneys are damaged and have impaired sodium excretion, what changes can help alleviate this?
Increase blood pressure to maintain normal sodium excretion (but long term high BP is damaging as well)
What is pressure diuresis?
Blood pressure raises & the urinary output increases to compensate and protect the body from BP increase.
What is the term for when blood pressure raises and sodium excretion increases as a result?
Pressure natriuresis
T/F: Pressure natriuresis and pressure diuresis usually occur concurrently.
True
If fluid intake is greater than urine output, where will the fluid accumulate temporarily?
Blood & interstitial spaces (thus incr blood volume and extracellular volume)
T/F: Salt sensitive individuals will see an increase in BP with very little salt intake.
True
Activation of the sympathetic nervous system will cause a dilation or constriction of renal arterioles?
Constriction–> decreased GFR
What are the big 4 hormones regarding kidney influence?
Angiotensin II
Aldosterone
ADH (Vasopressin)
Atrial Natriuretic Peptide (ANP)
Which hormone is considered one of the body’s most powerful controllers of sodium excretion?
Angiotensin II
High levels of sodium lead to (increased/decreased) production of renin?
Decreased
Decreased renin leads to decreased levels of ____, causing an increase in secretion of sodium.
Angiotensin II
T/F: Angiotensin II causes blood volume to increase.
False: Angiotensin II has little impact on extracellular volume or blood volume
Salt sensitive people have __ levels of sodium with a ___ renin secretion.
High; high (these individuals need excessively high BP to cause renin secretion to decrease)
What effect does increased aldosterone have on sodium and water reabsorption?
Aldosterone–> Incr. sodium and water reabsorption
What effect does increased aldosterone have on potassium excretion?
Aldosterone–> Incr. potassium excretion
T/F: When fluid deprived, ADH levels would be increased.
True
What is the effect of increased ADH?
Incr. reabsorption of fluid
Excrete sodium
Is fluid diluted or concentrated when there is an increase in ADH?
Concentrated, (ADH=thirsty and hold onto your fluids)
What causes a release of atrial natriuretic peptide?
Stretch receptors in the cardiac atria
Atrial natriuretic peptide would have what effect on GFR and reabsorption rate of sodium?
GFR would increase,
Sodium reabsorption would decrease, (or increased sodium excretion)
T/F: In a healthy individual, a small increase in arterial pressure will cause an increase in sodium excretion to maintain balance.
True
If fluid and proteins are leaking into the interstitium (edema), how do the kidneys respond?
Retain salt and fluid to restore blood volume