224
UNIT 3
Organ Systems
Figure 12-1.
Overview of the urinary system.
The
urinary system
plays an important role in eliminating the body’s metabolic wastes and toxins; controlling water and ion balance
and regulating blood pressure; maintaining the acid-base (pH) balance of the blood; and in reabsorbing and conserving nutrients.
The urinary system achieves these goals by F
ltering the blood and producing urine. The complex tubule system in the kidney helps
to reabsorb and readjust water and ion content and to excrete urine. The urinary system consists of two
kidneys
, two
ureters
, the
urinary bladder
, and the
urethra
. The
kidneys
are the organs that produce urine and accomplish the essential functions listed above.
After urine is produced, it passes through the ureters to the bladder for temporary storage, F
nally exiting the body through the
urethra.
Kidney
Urinary
bladder
Abdominal
aorta
Ureter
Renal artery
and vein
Inferior
vena cava
Urethra
General structure of the kidney:
I.
Renal cortex
A.
Renal corpuscles
B.
Proximal convoluted tubules
C.
Distal convoluted tubules
D.
Cortical collecting tubules
II.
Renal medulla (renal pyramids)
A.
Outer medulla
B.
Inner medulla
C.
Renal papillae
III.
Renal hilum
A.
Minor calyx
B.
Major calyx
C.
Renal pelvis
Functional and histological unit of the kidney:
I. Nephron
A.
Renal corpuscle
B.
Proximal convoluted tubule
C.
Loop of Henle
1. Descending limb
a. Thick descending limb (proximal straight tubule)
b. Thin descending limb (descending thin segment)
2. Ascending limb
a. Thin ascending limb (ascending thin segment)
b. Thick ascending limb (distal straight tubule)
D.
Distal convoluted tubules
II. Collecting system
A.
Cortical collecting tubule
B.
Collecting ducts
C.
Papillary ducts
Structures of the Kidney
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