Medical Terminology Simplified

7–61 Microscopic examination of the kidney reveals about one million nephrons,

all of which play a vital role in the maintenance of normal fluid balance (homeosta-

sis) in the body. The nephrons are located within the outer layer of the kidney, called

the (1) renal cortex, and the inner region, called the (2) renal medulla.

The first part of the nephron, the (3) glomerular capsule, also called Bowman capsule,

surrounds a tiny ball of coiled intertwining capillaries known as the (4) glomerulus.In

the first step of urine production, water, salts, sugar, urea, and other nitrogenous waste

products are filtered across the wall of glomerular capillaries and into the glomerular

capsule. This waste-containing fluid is known as renal filtrate.

Label the structures in Figure 7–7.

7–62 The collection of filtrate in the glomerular capsule flows into the long, twisted

tube called the (5)renal tubule, where reabsorptionof nutrients continues. The reab-

sorption process ensures that the body retains essential substances, such as glucose,

water, and salts. On the other hand, waste products of metabolism become toxic if al-

lowed to accumulate in the body. Thus, acids, drugs, and other wastes leave the body in

the urine. This final process of urine formation occurs in the (6) collecting tubule that

conveys the newly formed urine to the renal pelvis, which narrows into the ureter. The

urine flows through the ureters into the bladder for temporary storage. The bladder

eventually expels the urine through the urethra during the process of urination.

Label the structures of the nephron in Figure 7–7.

Frame 7–61to Frame 7–62

Microscopic Structures • CHAPTER 7 297297

Loop of

Henle

Urine drains to

renal pelvis

(1) ____ ____

(2) ____ ____

(6) ________

________

(3) ________

________

(5) ________

________

(4) ________

To renal vein

From renal artery

Figure 7-7Nephron and associated blood vessels. Arrows indicate the direction of blood flow
and flow of renal filtrate.