Week 11 Flashcards
Exam 4
Intracellular fluid (ICF)
is all the fluid within cells
Extracellular fluid (ECF)
Extracellular fluid (ECF) is all the fluid outside the cells.
What is included in ECF
ECF includes the interstitial fluid, the intravascular fluid, and the various transcellular fluids
Sodium concentration is regulated by:
The sodium concentration is regulated by the renal effects of aldosterone
Water balance is regulated primarily by:
antidiuretic hormone (ADH)
What percent of ECF does sodium account for?
Sodium (Na+) accounts for 90% of the ECF cations (positively charged ions)
What are the major anions?
- Chloride
- Bicarbonate
What acts to regulate water balance?
- Sodium
- Chloride
- Bicarbonate
How do sodium, chloride and bicarbonate act to regulate water balance?
Sodium in concert with chloride and bicarbonate, the two major anions (negatively charged ions), acts to regulate water balance by contributing to extracellular osmotic forces.
The serum sodium concentration is normally:
135 to 145 mEq/L
How is the serum sodium concentration normally maintained?
By renal tubular reabsorption within the kidney in response to neural and hormonal influences.
What does aldosterone regulate?
Hormonal regulation of sodium (and potassium) balance is mediated by aldosterone,
Where is aldosterone secreted from?
Secreted from the adrenal cortex.
Aldosterone is a component of what system?
renin-angiotensin-aldosterone system
Aldosterone secretion is influenced by a number of factors, including:
Circulating blood volume, blood pressure, and plasma concentrations of sodium and potassium
Where is renin released from:
Secreted by the juxtaglomerular cells of the kidney,
When is renin released?
When the circulating blood volume or blood pressure is reduced, renin is released.
What is another reason renin may be released?
Renin also is released when sodium levels are depressed or potassium levels are increased.
Once released, renin stimulates the formation of what?
Angiotensin I
Angiotensin I
an inactive polypeptide, from angiotensinogen
Where is angiotensinogen secreted by?
Secreted by the liver
Where are Angiotensin-converting enzyme (ACE) found?
Angiotensin-converting enzyme (ACE), found primarily in pulmonary vessels and to a lesser extent in endothelial and renal epithelial cells.
What does the Angiotensin-converting enzyme (ACE) do?
Converts angiotensin I to angiotensin II , a potent vasoconstrictor.
What does vasoconstriction do to blood pressure and renal perfusion?
Vasoconstriction elevates blood pressure and restores renal perfusion.