Flashcards in Renal Physiology (Part 2) Deck (170)
Which ion is the major cation of the ECF?
The reabsorption of Na+ into the ECF after filtration is critically important in maintaining what?
- normal ECF volume
- normal blood volume
- normal blood pressure
The kidneys ensure that Na+ _____ exactly equals Na+ ____, a matching process called what?
If Na+ excretion is less than Na+ intake, then the person is in _____ Na+ balance.
What happens if the person is in positive Na+ balance?
Extra Na+ is retained, therefore there is ECF volume expansion which causes blood volume and arterial pressure to increase. This may result in edema.
If Na+ excretion is greater than Na+ intake, then the person is in _____ Na+ balance.
What happens if the person is in negative Na+ balance?
Excess Na+ is lost from the body, therefore is ECF volume contraction which causes blood volume and arterial pressure to decrease.
How can a person have increased Na+ content but normal Na+ concentration?
If water content is increased proportionally
In nearly all cases, changes in Na+ concentration are caused by what?
Changes in body water content
*not Na+ content
Excretion of Na+ is __% of the filtered load.
Net reabsorption is __% of the filtered load.
Where does the bulk of Na+ reabsorption occur?
In the proximal convoluted tubule
__% of the filtered load is reabsorbed in the proximal convoluted tubule.
What is water reabsorption linked to in the proximal convoluted tubule?
__% of the filtered load is reabsorbed in the thick ascending loop of Henle.
Is the thick ascending loop of Henle permeable to water?
__% of the filtered load is reabsorbed in the terminal portions of the nephron (the distal tubule and the collecting ducts).
__% of the filtered load is reabsorbed in the early distal convoluted tubule.
__% of the filtered load is reabsorbed in the late distal convoluted tubule and collecting ducts. These structures are ultimately responsible for what?
the fine-tuning of Na+ reabsorption which ensures Na+ balance
In which part of the nephron are sites of action of the Na+ regulating hormone aldosterone?
the late distal convoluted tubule and collecting ducts
As already stated, the entire proximal convoluted tubule reabsorbs 67% of the filtered Na+, it also reabsorbs 67% of the filtered water. This tight coupling between Na+ and water reabsorption is called what?
The proximal tubule is also the site of what?
What is the first half of the proximal convoluted tubule called?
the early proximal convoluted tubule
The early proximal convoluted tubule performs the ______ priority reabsorptive work
In the early proximal convoluted tubule, what are the most essential solutes that are reabsorbed?
- amino acids
What are the 2 mechanisms by which solutes are reabsorbed into the proximal convoluted tubule?
What are the 5 cotransport mechanisms in the proximal convoluted tubule?
1) Na+ - glucose (SGLT)
2) Na+ - amino acid
3) Na+ - phosphate
4) Na+ - lactate
5) Na+ - citrate
Once Na+, glucose, amino acid, phosphate, lactate, and citrate are in the cell how are they extruded from the cell into the blood?
Na+ by way of the Na+ - K+ ATPase
Glucose and the other solutes are extruded by facilitated diffusion
What is the only contertransport mechanism in the proximal convoluted tubule?
Na+ - H+ exchange
Via the Na+ - H+ exchange system __ is transported into the lumen in exchange for __.