Flashcards in Renal System Deck (130)
What is a countercurrent system?
Inflow runs parallel to outflow for some distance; "u-shaped" tube
Name 3 countercurrent systems in the body.
1) loop of Henle (nephron)
2) vasa recta (capillaries of nephron)
3) blood flow to the testes through spermatic artery and veins
What is the difference in a countercurrent exchange and a countercurrent multiplier system? Which one of these does the kidney use?
What is the function of the countercurrent systems in the kidney?
What blood vessels supply the loop of Henle?
The _______ regulate the volume and composition of extracellular fluid.
The _______ is the functional unit of the kidney.
Metabolic end products are excreted by ________.
filtration; filtered into and trapped within the renal tubule
Concentration = __________
amount (of Na+)
volume (in water)
Osmolality is another term for ________.
Sodium Salts are _____% of the total osmolality of the ECF.
________ regulates Na+.
What is the normal range for osmolality?
300 mOsm/kg (range 270-310)
The kidneys maintain ECF volume by controlling _____ and ______ excretion.
salt (NaCl) and water
What are the 3 primary endocrine roles of the kidney?
1) erythropoietin--> acts on bone marrow to stimulate RBC production; chronic renal pt's may be anemic d\t low production of erythropoietin
2) RAS---> enzyme hormone system to regulate BP, K+ excretion, and Na+ reabsorption
3) vitamin D---> starts in the skin---> liver (picks up hydroxyl group---> kidneys (picks up another hydroxyl group)---> D3 (active form)
*chronic renal pt's may be hypocalcemic b\c vit D helps in the absorption of calcium from the intestine
Na+ concentration is another term for _______.
Blood is delivered to the glomerulus via the _______ arteriole and exits the glomerulus via the ______ arteriole.
Kidneys get approx ______ % of cardiac output.
25% or 1.25L (based on 5L/min CO)
The kidneys rework the ECF about once every ______, thereby maintaining its composition and volume.
once every 2 hours
*dialysis machines are only capable of reworking the ECF of anephric (kidney free) pt's once every 8-12 hours
What are the components of the renal tubule?
1) Bowman's capsule (encapsulates the glomerulus)
2) proximal tubule
3) loop of Henle
4) distal tubule
5) collecting duct
The loop of Henle adjusts concentration of ______ and ______.
Na+ and H2O
What occurs in the descending LOH?
osmosis--> H2O reabsorbed and Na+ left behind--> becomes concentrated
What occurs in the ascending LOH?
Na+ reabsorbed and H2O stays behind
Aldosterone effects the ______ of the renal tubule, and ADH effects the _______ of the renal tubule.
What are the 4 primary functions of the kidney?
Where does 2/3rds of the reabsorption of H2O, Na+, etc... take place?
Where does secretion in the renal tubule take place?
proximal tubule (muscle relaxants, etc)
Where do loop diuretics work?
THICH ASCENDING LIMB (TAL) of the LOH
*inhibit the body's ability to reabsorb Na+--> H2O follows Na+
What diuretics work on the distal tubule?
thiazide-type diuretics--> HCTZ
*inhibit Na+ chloride symporter--> retention of water in the urine, as water normally follows penetrating solutes
*The long-term anti-hypertensive action is based on the fact that thiazides decrease preload, decreasing blood pressure. On the other hand the short-term effect is due to an unknown vasodilator effect that decreases blood pressure by decreasing resistance.