Flashcards in Urinary System Deck (40):
What is the difference between excretion and elimination?
-Excretion removes metabolic waste while elimination removes indigestible material (dietary fiber)
What are the principle organs involved in excretion?
-Lungs, liver, skin, kidneys
What are the units comprising the kidney called?
What are the three regions of the kidney?
-Outer cortex, inner medulla, renal pelvis
What structures are in the outer cortex regions?
-Bowman's capsule/glomerulus and convoluted tubules
What structures are in the medulla?
-Loop of Henle and collecting duct
What structures are in the pelvis?
Trace the flow of the kidney.
-Capsule --> Proximal Convoluted Tubule --> Loop of Henle --> Distal Convoluted Tubule --> Collecting Duct --> Ureter --> Urinary Bladder --> Urethra
What surrounds most of the nephron?
Peritubular capillary - aids in reabsorption of aa, glucose, salts, water
What are the three steps of urine formation?
-Filtration, Secretion, Reabsoption
What drives filtration?
-Passive, driven by hydrostatic pressure of blood
What is relation of filtrate and blood plasma?
What is secreted into filtrate in secretion step?
-Waste substance (acids, ions, metabolites) from interstitial fluid by passive/active transport
What is reabsorbed and returned to blood?
-Glucose, salts, amino acids (active)
Where does reabsorption occur mainly?
-Proximal convoluted tubule (active)
After reabsorption, what is formed?
-Concentrated urine hypertonic to blood
What is the primary function of the nephron?
-Clean blood plasma of unwanted substances through selective permeability and osmolarity gradient of nephron
Where is the primary site of nutrient reabsorption?
-Proximal convoluted tubule
Where is the major site of secretion of substances into the filtrate?
-Distal convoluted tubule
What is the descending loop of Henle permeable to?
-Permeable to water but not to ions or urea
What is the thin ascending limb of the loop of Henle permeable to?
-Permeable to ions (passive), impermeable to water
What is the thick ascending limb of the loop of Henle's function?
-Active reabsorption of sodium, potassium, and chloride
What creates the osmolarity gradient between the tubules and interstitial fluid?
-Na+ and Cl-
Which direction does tissue osmolarity increase from?
-Cortex to inner medulla
What drives the gradient?
-Counter-current-multiplier system (use energy to create concentration gradient)
The interstitial space in the medulla of the kidney is _________ in relation to filtrate in renal tubule.
Osmosis allows water to flow from ____ to the ____ when filtrate travel down collecting ducts to pelvis/ureter.
From ducts to interstitial fluid
Where does the water reabsorbed from collecting ducts go?
-Travels from capillaries in medulla to systemic circulation
What hormone regulates the permeability of the collecting ducts to water?
-ADH (vasopressin) secreted by hypothalamus
-Increase permeability to water --> reabsorption --> more concentrated urine
What is purpose of aldosterone?
-Increase transport of Na+ (excretion) along distal convoluted tubule/collecting duct
-Increases water reabsorption
How does ADH increase water reabsorption?
-Opens more aquaporins
ADH and aldosterone both...
...decrease urine output and increase blood pressure.
-inhibit sodium reabsorption in ascending loop (loop diuretics)
-inhibit sodium-chloride transporter in distal convoluted tubule
What is body fluid pH?
What are the types of acid-base disorders?
Which type of A-B disorder takes longer to compensate for?
-Respiratory since they are compensated for by the kidney changing levels of HCO3-
What is the defect and compensation method of metabolic acidosis?
-Cause: low HCO3-
-Compensate: low pCO2
What is the defect and compensation method of respiratory acidosis?
-Cause: high pCO2
-Compensate: high HCO3-
-Cause: high HCO3-
-Compensate: high pCO2