Renal Physiology Flashcards
Kidneys can filter entire blood supply every ___ minutes, as well as filtrate at a rate of ____ L/min.
every 30 minutes; 1.1 L/min max rate
Kidneys utilize ___-___% of our cardiac output
20-25%
What functions are the kidneys responsible for in our bodies? (4)
- Maintaining homeostasis of fluid, electrolytes, pH
- Blood pressure
- Erythropoiesis by synthesizing EPO
- Synthesize active vitamin D
Blood enters the kidney through the _____ _____.
Renal artery
Blood travels to individual nephrons via the _____ ____.
Afferent arteriole
Filtered blood is collected by the _____ _____ and exits through the efferent arteriole
Glomerular capillaries
Urine is collected and removed through the _____.
Ureter
How many nephrons are in each kidney?
1 million
Unit of nephron responsible for filtration
Glomerulus
Unit of nephron that collects filtrate
Bowman’s capsule
Unit of nephron responsible for most (60%) of the reabsorption back into the blood stream of particles such as Na+, H20 and glucose
Proximal convoluted tubule
Unit of nephron that is responsible for reabsorption via counter-current multiplication using H2O
Loop of Henle
Which particles passively diffuse? (6)
- Na+
- K+
- Cl-
- H2O
- Glucose
- Urea
Part of the Loop of Henle that is responsible for counter-current reabsorption of H2O.
Descending limb
Part of Loop of Henle that is responsible for active reabsorption of Na+, Cl-, and K+ (ions)
Ascending limb
Meaning putting back into bloodstream
Reabsorption
Meaning tissues put material back into kidney
Secretion
Describe briefly how the counter-current reabsorption works.
Ions are actively moved out of the ascending loop of Henle, which creates a gradient for water to passively follow out of the descending loop of henle and back into blood stream.
Part of the distal convoluted tubule which monitors blood pressure and can alter fluid and ion retention
Juxtaglomerular apparatus
Part of the nephron that reabsorbs H2O and urea
Collecting duct
If the afferent artery diameter increases, the GFR
Increases
If the efferent artery diameter increases, the GFR
Decreases
If the afferent artery diameter decreases, the GFR
Decreases
If the efferent artery diameter decreases, the GFR
Increases
What does the RAAS system respond to?
Drop in blood pressure or change in blood sodium levels
Which enzyme does the kidney release in response to decreased BP or SV?
Renin
What effect does renin have?
Renin converts angiotensinogen to angiotensin I
What happens to angiotensin I?
Angiotensin I is converted to angiotensin II by ACE
What effect does angiotensin II have on the cardiovascular system?
Causes vasoconstriction, which increases vascular resistance and leads to increased blood pressure
What effect does angiotensin II have on the kidneys?
Causes them to release aldosterone which increases salt and H2O retention and leads to increased blood pressure
Formula for MAP
MAP = SV x HR x Resistance
What does the kidney modify in the MAP equation?
SV and Resistance
