Disorders of Extracellular Fluid Volume: Basic Concepts Flashcards
What determines the extracellular fluid (ECF) volume?
The total amount of Na(^+) and its accompanying anion (Cl(^-))
The retention or excretion of Na(^+) by the kidneys is critical for ECF volume regulation.
What is the role of baroreceptors in ECF volume regulation?
They perceive changes in volume and send signals to the vasomotor center
Baroreceptors are located in the vascular system and other areas of the body.
List the components that participate in the regulation of NaCl.
- Sensors
- Afferent neural mechanisms
- Coordinating integrative control center
- Efferent neural mechanisms
- Kidneys
What happens to Na(^+) excretion in low salt intake?
Na(^+) excretion decreases
This occurs as the body conserves Na(^+) and water to restore volume.
What are the major conditions associated with excess fluid volume?
- Heart failure
- Cirrhosis
- Nephrotic syndrome
Define Effective Arterial Blood Volume (EABV).
A component of ECF volume that perfuses tissues
EABV is not directly measurable and reflects ‘underfilling’ of the arterial vascular system.
How do high-pressure afferent mechanisms respond in heart failure?
They sense arterial underfilling, inducing neurohumoral mechanisms that result in renal Na(^+) and water retention.
What is the role of Starling forces in fluid exchange?
They govern the movement of fluid across capillaries into the interstitial space
Starling forces include hydrostatic and oncotic pressures.
What is the Starling equation used for?
To describe the rate of fluid flow across the capillary
The equation incorporates hydrostatic and oncotic pressures.
Fill in the blank: Edema is formed when Starling forces are _______.
altered
What causes edema formation in heart failure?
Accumulation of fluid in the venous end raises hydrostatic pressure, overcoming net reabsorption pressure.
How does nephrotic syndrome contribute to edema formation?
Increased ( K_f ) of capillary endothelium and activation of ENaC by serine protease
This permits protein leakage and contributes to fluid retention.
True or False: EABV and ECF volume are identical in conditions like heart failure.
False
What is the primary mechanism by which the kidneys respond to increased ECF volume?
Inhibition of salt- and water-retaining mechanisms and activation of salt-losing mechanisms.
What effect does sympathetic nervous system (SNS) activation have on renal blood flow?
It causes renal afferent and efferent arteriolar vasoconstriction, resulting in decreased renal blood flow.
What triggers the activation of renin-angiotensin-aldosterone system (RAAS) during low salt intake?
Decreased ECF volume sensed by baroreceptors.
Define hydrostatic pressure of the capillary (P(_c)).
Pressure that pushes fluid out of capillaries.
What is the consequence of persistent low EABV in cirrhosis?
Activation of neurohumoral mechanisms causing Na(^+) and water retention.
What is the main focus of Rondon-Berrios’ 2011 study?
New insights into the pathophysiology of oedema in nephrotic syndrome
Nefrologia. 2011;31:148–54.
What did Schrier RW discuss regarding effective blood volume in edematous disorders?
Decreased effective blood volume in edematous disorders: implications
J Am Soc Nephrol. 2007;18:2028–31.
What topic does Schrier RW cover in his 2018 publication?
Renal sodium excretion, edematous disorders, and diuretic use
In: Schrier RW, editor. Renal and electrolyte disorders. 8th ed. Philadelphia: Wolters Kluwer; 2018. p. 47–85.
What is the focus of Siddall EC and Radhakrishnan J’s 2012 research?
The pathophysiology of edema formation in the nephrotic syndrome
Kidney Int. 2012;82:635–42.
What do Slotki IN and Skorecki KL discuss in their chapter?
Disorders of sodium balance
In: Yu ASL, et al., editors. Brenner & Rector’s the kidney. 11th ed. Philadelphia: Elsevier; 2020. p. 390–42.
Fill in the blank: The study by Schrier RW in 2007 discusses decreased effective blood volume in _______.
edematous disorders
True or False: Rondon-Berrios’ study from 2011 provides insights into the pathophysiology of edema in nephrotic syndrome.
True
What does the 2020 edition of Brenner & Rector’s the kidney cover?
Disorders of sodium balance
Edited by Yu ASL, et al., 11th ed. Philadelphia: Elsevier; 2020. p. 390–42.
What is the title of A. S. Reddi’s work referenced in the document?
Fluid, Electrolyte and Acid-Base Disorders
DOI: https://doi.org/10.1007/978-3-031-25810-7_6
