Lecture 7 - The Kidney and Diuretics 1 Flashcards
What are the functions of the kidney?
Regulation of extracellular (body) fluid volume
Maintenance of ion balance (electrolyte) and pH
Excretion of foreign substances - excretion pathway including drugs
Renin secretion and activation of the RAAS
Name the key facts about the nephron
Basic functional unit of the kidney
Final reabsorption takes place here
Individual units some projected into the medulla (1/3) the remaining sit in cortex and cortisol nephron
Key facts about the kidney
120ml of blood per min - 20-25% of CO
120L of blood per day
99% water and most of filtered sodium reabsorbed including all good components e.g. glucose, salts and water
Define glomerulus
Site for ultrafiltration of blood
What is filtered and retained in the kidney?
Freely filtered (<7ka including glucose, amino acids, ions Na+, K+,Cl-, H+, Ca2+, Mg2+ - bicarbonate and water)
Some can be retained (7-70kDa)
Not filtered >70kDa - including albumin, other plasma proteins and blood cells
Define reabsorption or absorption
A movement of solutes and water from tubular filtrate into intestinal fluid and plasma
Define secretion
A movement of solutes and water from the plasma and interstitial fluid into the tubular filtrate
Define trancellular pathway
Through the epithelial cell and across the luminal and the basolateral membrane
Define paracellular pathway
Through tight junctions between the epithelial cells
Define excretion
An extrusion of solutes and water in the tubular filtrate by the kidneys
How much tubular sodium reabsorption occurs in the proximal convoluted tubule?
60-70%
How much tubular sodium reabsorption occurs in the thick ascending limb (TAL) of the loop of Henle?
20-30%
How much tubular sodium reabsorption occurs in the distal tubule?
5-10%
How much tubular sodium reabsorption occurs in the collecting duct (CD) and collecting tubule (CT)?
1-3%
Define diuresis
Increased excretion of urine
