AUBF LEC Flashcards
3 processes of urine formation
Glomerular filtration
Tubular reabsorption
Tubular secretion
What enzyme converts ANGIOTENSIN I TO ANGIOTENSIN II
Angiotensin converting enzyme
Secretion of aldosterone stimulates?
SODIUM REABSORPTION
Secretion of ADH stimulates?
WATER REABSORPTION
Permeable to water and low molecular weight solutes while it excludes proteins larger than albumin
Glomerular filtration barrier
The ____ serves as a non selective filter of plasma substances with molecular weights less than 70, 000
Glomerulus
3 glomerular filtration barrier cellular layers;
Capillary wall membrane
Basement membrane
Visceral epithelium of the bowman’s capsule
Specific gravity of ultrafiltrate
1.010
Glomerular filtration rate:
90- 120 ml/minute
Final urine volume of:
600- 1800 ml
Results from the reduction of the size (diameter of lumen) of efferent arterioles snd glomerular capillaries
- forces fluid to the bowman’s space at a pressure of 55mmHg
Hydrostatic pressure
This type of pressure is exerted by the fluid in the bow,an’s space that opposes filtration by 15 mmhg
Capsular hydrostatic pressure
This type of pressure is exerted by unflitered proteins in the glomerular capillaries that also opposes filtration at a magnitude of 30 mmHg
Blood colloid osmotic pressure/ oncotic pressure
This pressure contains the remaining 10 mmhg outcome of these pressure differences that is favorable in the formation of the plasma ultrafiltrate
Net filtration pressure
99% (majority of the plasma ultrafiltrate that enters the renal tubules are reabsorbed)
Tubular reabsorption
This transport requires no energy and allow movement of solutes along concentration gradient which is from high solute concentration to a low solute concentration
PASSIVE TRANSPORT
This transport requires energy to move solutes as it moves against a concentration gradient (low solute to high)
Active transport
How many percent of the ultra-filtrate is reabsorbed in the proximal convoluted tubules
80%
TRUE OR FALSE: Sodium and chloride are partly reabsorbed while glucose and proteins are almost completely reabsorbed
True
As the amount of solute increases, the rate of reabsorption increases until the maximum rate of reabsorption is reached
MAXIMAL TUBULAR REABSORPTIVE CAPACITY (Tm)
Solutes that exhibit Tm includes?
Glucose
Amino acids
Proteins
Phosphates
Sulfates
Uric acid
Refers to the concentration of solute in plasma ar which the maximal tubular reabsorptive capacity of the tubules has been exceeded
Renal threshold
Renal threshold of glucose and its tm?
160-180 mg/dl
Tm: 350 mg/min
Water is reabsorbed throughout the nephron via?
OSMOSIS
The tubular epithelium in the ____ is selectively impermeable to water despite the presence of an osmotic gradient between the tubular lumen and medullary interstitium due to the histologic characteristics of its epithelium
Thin ascending limb of the loops of henle
Blood ph is maintained by the:
buffering system, respiratory system and kidneys
In cases of alkalosis, hydrogen ions are? And incases of acidosis?
Alkalosis= hydrogen ions are retained
Acidosis= hydrogen ions are secreted
The osmotic gradient of the renal medulla makes it the only tissue in the body that is ? With respect to normal plasma
HYPERTONIC
A polymer fructose, an extremely stable substance that is neither reabsorbed, nor secreted by the tubules
INULIN
3 mechanism by which the tubules participate in maintaining blood ph
- Secretin of H ion in the proximal tubular lumen that reacts with HCO3 to form carbonic acid
-The HCO3 present in the tubular cells, diffuses to the interstitial fluid and peritubular capillaries to resupply the blood buffer system - Secretory mechanism that involves neutral phosphate salts present in the tubular lumen
Phosphoric acid + ( forms monosodium phosphate or mononasic phosphate
- Depends on ammonia secretion and subsequent exchange of sodium for ammonium ions
This actively happens in the loops of henle
Countercurrent multiplier mechanism
This passively happens and involves the vasa recta
Countercurrent exchange mechanism
Water is passively reabsorbed in the descending loop of henle with solutes not being reabsorbed with t he exception of ure
Countercurrent multipliers mechanism
