Questions & Answers
What causes extremely high blood pressure in the glomerular capillaries?
The diameter of the afferent arteriole is greater than the diameter of the efferent
arteriole. The difference in diameter causes high blood pressure in the glomerular
capillaries.
Describe in detail what happens during an emergency to control the rate of
blood to the kidney.
During these times the renal autoregulatory system is superseded by higher level
nervous system controls. When the nervous system takes over regulation, the
afferent arterioles diameter is narrowed by sympathetic nerve fibers. The release
of the hormone epinephrine by the adrenal medulla causes a decrease in renal
blood flow and decreases the GFR. Constriction of the renal arteries is only to be
used for a short time.
What is countercurrent flow? How does the nephron use this to maintain
homeostasis?
Countercurrent flow is the movement of fluids in opposite directions through
adjacent channels. In the nephron, filtrate flows in one direction through the renal
tubules while blood in the adjacent blood vessels flows in the opposite direction.
Describe the action of aldosterone on the concentrations of sodium and
hydrogen in the filtration.
Sodium is removed from the filtrate while hydrogen is pumped inside the filtrate.
, Describe the action of aldosterone on the concentrations of sodium and
potassium in the filtrate.
Sodium is pumped out of the filtrate to be returned to the blood while potassium
(K+) is excreted in urine.
Describe the action of a drug that increases the rate of flow through the
nephron.
This would be a diuretic. When the filtrate moves at a faster rate through the
nephron it allows less time for ions to be removed from the filtrate.
A person is hyperventilating. This falls under what control mechanism? Explain
what hyperventilation accomplishes.
Respiratory control- Hyperventilation is an increase in the respiratory rate, helping
to remove additional CO2. Within minutes increasing amounts of CO2is removed.
Removing CO2 uses up H+ causes the pH to rise (becomes more alkaline) and
restores correct blood pH.
Hypoventilation is a part of what control mechanism? Explain what
hypoventilation accomplishes.
It means that blood ph is rising, respiratory rate is slowing down to addCO2
Your patient was just admitted to the hospital with renal failure. For
the following questions, use the blood values of: pH =7.1, PCO2 = 30 mm, HCO3-
= 20 mEq/L
A. Determine if the patient is in acidosis or alkalosis.
B. Is the cause respiratory or metabolic?
C. Is the condition being compensated?
D. If compensated, what is the body doing to compensate?
A. Acidosis (<7.35)
B. Metabolic (HCO3-<22)
C. Yes (PCO2 <35)
D. Hyperventilation to increase CO2 elimination