renal physiology Flashcards
(23 cards)
What are the three main processes involved in urine formation?
Filtration (in glomerulus), reabsorption (from tubular fluid to blood), and secretion (from blood to tubular fluid).
What is the function of the glomerulus in the nephron?
To filter blood plasma, forming filtrate that enters the Bowman’s capsule.
How does the kidney regulate acid-base balance?
By reabsorbing bicarbonate and excreting hydrogen ions, either as free H+, ammonium ions, or titratable acids.
What is the role of the renal system in water-volume regulation?
It adjusts urine output and osmolality through hormonal control (e.g., ADH), counter-current mechanisms, and sodium balance.
What is glomerular filtration rate (GFR)?
The volume of filtrate produced by the kidneys per minute, a key measure of renal function.
What does clearance mean in renal physiology?
It is the volume of plasma from which a substance is completely removed per minute; used to evaluate kidney function.
What is the role of aldosterone in sodium balance?
Aldosterone increases sodium reabsorption and potassium excretion, affecting blood volume and pressure.
How does the bicarbonate buffer system regulate blood pH?
It maintains pH via reversible reactions involving carbonic acid, bicarbonate, and CO₂, according to the Henderson-Hasselbalch equation.
What is the consequence of metabolic acidosis?
A drop in blood pH due to reduced bicarbonate; kidneys compensate by increasing acid excretion and bicarbonate reabsorption.
How does ADH regulate water reabsorption?
ADH increases water permeability in the collecting duct, promoting water reabsorption when plasma osmolality is high.
What is the structure and function of the nephron?
The nephron is the functional unit of the kidney, consisting of a vascular and a tubular component. It filters blood, reabsorbs vital substances, and secretes waste into urine.
What are the basic processes involved in urine formation?
Filtration, reabsorption, and secretion.
What is glomerular filtration rate (GFR)?
The rate at which the kidneys filter blood, often measured in ml/min. Used to assess kidney function.
What is renal clearance?
The volume of plasma cleared of a substance per unit time, used to estimate kidney function.
How does the nephron regulate sodium and potassium balance?
Via selective reabsorption and secretion influenced by aldosterone and the renin-angiotensin system.
What is the role of ADH in water balance?
ADH increases water reabsorption in the collecting duct, concentrating urine and conserving water.
What is counter-current multiplication?
A mechanism in the loop of Henle that creates an osmotic gradient, allowing concentrated urine formation.
What is buffering capacity in acid-base balance?
The ability of a buffer system (e.g., bicarbonate) to resist changes in pH by neutralizing H⁺ or OH⁻ ions.
How does the kidney regulate blood pH?
By reabsorbing bicarbonate and excreting hydrogen ions via NH₄⁺, titratable acids, or free H⁺.
What is the Henderson-Hasselbalch equation used for?
To estimate pH based on bicarbonate concentration and partial pressure of CO₂: pH = 6.1 + log([HCO₃⁻]/(0.03 × PCO₂)).
What are metabolic and respiratory acidosis?
Metabolic acidosis: ↓HCO₃⁻; Respiratory acidosis: ↑CO₂; both lower blood pH.
What are metabolic and respiratory alkalosis?
Metabolic alkalosis: ↑HCO₃⁻; Respiratory alkalosis: ↓CO₂; both raise blood pH.
