Physio/simple/renal

Front 1

Sodium is the most abundant extracellular cation. TRUE/FALSE

Back 1

TRUE. Deficiency may result in neuromuscular dysfunction. Excess may result in hypertension and fluid retention.

Front 2

Most sodium excretion occurs where?

Back 2

Almost all occurs through the kidney.
Non renal means of sodium excretion include sweating, feces, vomiting diarrhea, hemorrhage and burns.

Front 3

The amount of sodium reabsorption in the proximal tubule remains about the same regardless of changes in the GFR. TRUE/FALSE

Back 3

TRUE.

Front 4

What is glomerular tubular balance?

Back 4

This helps to maintain the levels of sodium and water in the body.

Front 5

What is tubuloglomerular feedback?

Back 5

This is an auto regulatory mechanism that also guards against the effects of changes in GFR.

Front 6

What is the macula densa?

Back 6

If there is an increase in fluid flow through the renal tubules, the macula densa senses this and feeds back a local chemical influence that constricts the afferent aretrioles, thereby decreasing the GFR.

Front 7

What is the difference between the G-T balance and the T-G balance?

Back 7

The G-t balance(what the glomerular gives to the tubules) guards against an increased GFR by increasing sodium reabsorption. T-G feedback(the information that the tubules feed back to the glomerulus) guards against an increaqsed GFR by decreasing GFR.

Front 8

Why does most sodium end up reabsorbed?

Back 8

because active transport is involved in the reabsorption process and the sodium is reabsorbed against an electrochemical gradient.

Front 9

is it true that that water, but not sodium reabsorption occurs in the descending loop of Henle.

Back 9

Yes. Infact sodium reabsorption, but not water reabsorption occurs in the ascending loop of Henle.

Front 10

Why is sodium and water absorbed in different places along the loop?

Back 10

This ensures that the interstitium outside the ascending limb is hyperosmolar. as tubular fluid continues beyond the ascending limb of the loop and into the collecting tubule, where water can leave the tubule, water exits into the body circulation, reducing the volume of urine.

Front 11

What happens as this reduced volume continues down the collecting duct?

Back 11

More water passively leaves to enter the surrounding hyperosmotic interstitium, thereby enabling the urine to be concentrated, even more than plasma.

Front 12

Why do loop diuretics cause less hyponatremia than do thiazide diuretics?

Back 12

Thiazide diuretics act on the distal convoluted tubule, because there is still a last chance for sodium to be reabsorbed in the DCT when loop diuretics are used.
Loop diuretics cause more of a diuresis than do thiazides, because by blocking sodium transport in the loop area, they prevent the interstitium in the loop area from becoming very hyperosmotic.

Front 13

One can conclude that hyperosmolarity of the interstitium is important for concentrating the urine. TRUE/FALSE?

Back 13

TRUE.

Front 14

How many liters of water, filter through the glomerular membranes of the kidney per day in a 70 kg person?

Back 14

180 liters.

Front 15

When is ANF produced?

Back 15

It is produced in response to dilation of the cardiac atria, as might occur with excessive blood volume, induces sodium excretion by decreasing sodium reabsorption.

Front 16

Can sodium absorption occur as an isolated event?

Back 16

No. Sodium cations need to either carry with them chloride or other anions(to avoid charge buildup in the tubular lumen) or exchange with secreted potassium or H+ cations.

Front 17

HCO3- ions carry sodium ions with them when they are reabsorbed through the peritubular capillary side of the renal tubule cell. TRUE/FALSE

Back 17

TRUE.

Front 18

Can bicarbonate ions pass easily through the tubular lumen side of the renal tubular cell?

Back 18

NO, but they can pass through indirectly as CO2, after combining with secreted H+ ions.

Front 19

What happens to H+ ions in alkalosis?

Back 19

In this condition, the blood pH is elevated. There is little H+ ion to exchange with sodium in the kidney and little H+ to facilitate bicarbonate reabsorption. Therefore, reabsorption of sodium and HCO3- decreases, while their excretion increases.