As this section from a volume of QJM entitled " Why do older patients die in a heatwave? " says: Older subjects have " diminished renal tubular conservation of sodium and water during periods of dehydration."

正 QJM 中题为“为什么老年人会热死”这部分内容所说：“老年人在脱水情况下，肾小管中钠和水的储备减少。”

Now, before we dive too far in here, let's re-draw the nephron so that the structure of the renal tubule is a little more accurate.

现在，趁还没有学得更深，我们来画一个肾单位，让肾小管的结构更加精确。

The underlying cause is hyperuricemia— too much uric acid in the blood, which results in the formation of sharp, needle-like crystals, in areas with slow blood flow like the joints and the kidney tubules.

引起痛风的原因是高尿酸血症，即血液中的尿酸含量过高，过多的尿酸会在血流缓慢的，关节腔和肾小管，形成尖锐的细针样结晶。

Now, these two make their way to the nephron of the kidney, and at this point in the proximal convoluted tubule, phosphate usually gets reabsorbed back into the blood via sodium-phosphate cotransporters.

接下来，们到达了肾小管的肾单位处，在近曲小管的这里，磷酸过钠-磷协转运蛋白被重新吸收到血液中。

Each nephron consists of a round renal corpuscle that resides up in the cortex, followed by a long and winding renal tubule that loops around between the cortex and the medulla.

每个肾单位由一个位于大脑皮层的圆形肾小体组成，其次是一个长而弯曲的肾小管，在大脑皮层和髓质之间循环。

If Leptospira gets to the kidneys, it may infect the interstitium, causing interstitial nephritis, or it may cause an inflammatory reaction that damages the renal tubules, resulting in acute tubular necrosis.

果钩端螺旋体进入肾脏，它会感染肾间质而引起间质性肾炎，也能引发炎性反应损伤肾小管，导致急性肾小管坏死。

These pumps drive potassium from the blood into the cells and from there it flows down its concentration gradient into the tubule to be excreted as urine.

这些泵驱使钾从血液进入细胞内，细胞内的钾离子再顺着浓度梯度进入肾小管，以尿液形式排泄。

Within each kidney, there are about 1 million nephrons, and each nephron is made up of a renal corpuscle and a renal tubule.

每个肾约有100万个肾单位，每个肾单位由肾小体、肾小管组成。

Aquaporins allow water to move quickly in and out of the cells.

水道蛋白允许水分快速过肾小管细胞。

This kind of intrinsic control, or autoregulation, is helpful in controlling the filtration rate through normal ranges of blood pressures, but the kidneys mostly regulate urine concentration at the other end of the nephron tubules.

这种内在控制或自动调节有助于过正血压范围控制过滤率，但肾脏主要调节肾小管另一端的尿液浓度。

This external balancing act is largely taken care of by the kidneys, where excess potassium is secreted into a renal tubule and excreted in the urine.

肾在外钾平衡起主要作用，它可以把多余的钾分泌到肾小管中，然后从尿排出。

Calcitriol increases renal tubular reabsorption of calcium which reduces the loss of calcium in the urine.

骨化三醇可以增加肾小管对钙的重吸收，减少尿钙。

This is called tubular secretion, and it transports only select kinds of waste that have already made their way into the blood that's in the peritubular capillaries, ready to leave the kidneys.

这叫做肾小管分泌物，它只运送特定种类的废物，这些废物已经进入管周毛细血管中的血液，准备离开肾脏。

These peritubular capillaries then reunite to become the cortical radiate veins, then the arcuate veins, then interlobar veins and finally into the left and right renal veins which connect to the inferior vena cava.

这些肾小管周围毛细血管网将重新汇聚成小叶间静脉，然后汇聚成弓状静脉、叶间静脉，最终汇入左右肾静脉；肾静脉又与下腔静脉相。

As the filtrate leaves the Bowman's capsule it flows into the renal tubule, which is surrounded by the peritubular capillaries.

滤液离开肾小囊后流入肾小管，后者被管周毛细血管网包围。

The more ADH floating around in the blood, the more aquaporins are available to facilitate water movement through the cell.

血液内的ADH越多，就会有越多的水道蛋白促进水分过肾小管细胞回到循环中。

Hypercalciuria can result from impaired renal tubular reabsorption of calcium, which leaves a lot of calcium behind in the tubule.

高尿钙可因肾小管重吸收钙功能不全导致，因此肾小管中残存了大量的钙。

So as a quick recap, intrarenal AKI is kidney injury caused by something within the kidneys themselves, which could be the tubules as in acute tubular necrosis, the glomerulus as in glomerulonephritis, or the interstitium as in acute interstitial nephritis.

好！快速回顾一下：肾性急性肾损伤是由肾脏内部引起的急性肾损伤，可能是小管，急性肾小管坏死；或肾小球，肾小球肾炎；或肾间质，急性间质性肾炎。

Now, all the stuff that get squeezed out of the blood into the glomerulus is called filtrate, which is then sent along to the elaborately twisting three-centimeter-long renal tubule.

现在，所有从血液中挤出进入肾小球的物质被称为滤液，然后被送到精心扭曲的三厘米长肾小管。

When ADH is high on the other hand, aquaporins grab much of the water passing through the these tubes and throws them back into the blood.

当ADH水平高时，水道蛋白将大量水分从肾小管内重吸收回血液循环中。