Chapter Twelve: Urinary System 287
OVERVI EW OF THE URINARY SYSTEM The urinary system consists of two kidneys, two ureters, a urinary bladder, and a urethra. The right kidney is a little more inferior than the left kidney due to the presence of the liver on the right side of the body. The kidneys are located near the twelfth vertebra and extend to the third lumbar vertebra. They receive blood from the renal artery. The kidneys are retroperitoneal, meaning that they are posterior to the parietal peritoneum. The ureters are also retroperitoneal and take urine to the bladder. Since the urinary bladder is located anterior to _~ the parietal peritoneum it is called anteperitoneal. Label the organs of k the urinary system and use separate colors for the kidneys, ureters, urinary bladder, and urethra.
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a. _
--'..;---- Psoas major muscle b. _
c. _
Answer Key: a. Kidney, b. Ureter, c. Urinary bladder, d. Urethra, e. Renal artery Chapter Twelve UPLANd'· I 289 Urinary System I me lea
KIDNEY The kidney is a bean-shaped organ. The outer surface of the kidney is covered by the renal capsule. The depression on the medial side is the hilum where the renal artery enters the kidney and the renal vein and a. _ the ureter exit. The kidney is sectioned in the coronal plane to study the internal anatomy. The --~~...c__I renal capsule is a thin membrane on b. the exterior of the kidney. Deep to the capsule is the renal cortex where filtration takes place in the kidney. c. _ The renal medulla is deep to the cortex and it is divided into renal columns and renal pyramids. Each pyramid ends in a papilla and this d. _ drips urine into smalJ funnel-shaped structures called the minor calyces (calyx singular). The minor calyces join to form the major calyces and e. _ these, in turn, take urine to the renal pelvis. The renal pelvis occupies most of the renal sinus, a space in the kidney. The renal pelvis takes f. _ urine to the ureter on the medial side of the kidney. Blood travels to the kidney by the renal artery. From there the blood moves into g._----- segmental arteries and then interlobar arteries. From the interlobar arteries the blood travels h. _ to the arcuate arteries. These arteries are the dividing structures between the renal cortex and the d. _ renal medulla. From the arcuate arteries blood flows into the interlobular arteries. Label the parts of the kidney and associated structures. Use one color for the cortex and different shades of another color for the renal pyramids and columns. Color the renal artery e. _ red and the renal vein blue. Use yellow for the pelvis and ureter.
n. _ p._-----
a. _
Answer Key: a. Renal artery, b. Hilum, c. Renal vein, d. Renal pelvis,e. Ureter, q._----- f. Renal capsule, g. Major calyces, n. _ h. Renal sinus, I. Renal cortex,J. Renal pyramid (in renal medulla), k. Papilla, I.Renal column, m. Minor calyces, n. Segmental arteries, o. Interlobar artery, p. Interlobularartery, q. Arcuate arteries Chapter Twelve I meClical 291 Urinary System
URINARY BLADDER The urinary bladder is a storage organ for holding urine. The ureters enter the bladder at the ureteral orifices and the urethra exits the bladder inferiorly. These three openings make a triangular region known as the trigone at the posterior wall of the bladder. The urethra is the external tube that takes urine voided from the urinary bladder to outside the body. The urethra in the female is much shorter than in the male, which makes females more susceptible to bladder infections. The wall of the bladder consists of smooth muscle Peritoneum called the detrusor muscle and an inner lining of transitional epithelium. Label the features of the bladder, urethra, and associated structures and color them in.
Urethral sphincter muscle Female Urinary System
g.------
a.
b.-- _ Prostate gland ------"-,--;-
f. Answer Key: a. Ureter, b. Urinary bladder, c. Detrusor muscle, d. Ureteral orifice,e. Trigone, f. Urethra, g. Right kidney Male Urinary System Chapter Twelve I mKAPeLANd'-Ical 293 Urinary System
THE NEPHROI\J a. _ b.-- _ The functional unit of the kidney is the nephron. It is here that material a. _ is filtered from the blood; some material is lost in the urine while other material is reabsorbed back into the cardiovascular system. The renal corpuscle of the nephron includes the glomerulus and the glomerular (Bowman's) capsule. The lining of the capsule wraps around the glomerulus and filtered rT material enters the nephron at this d.--- point. The glomerular capsule leads f.- _ to the proximal convoluted tubule. This tubule has a brush border consisting of many microvilli and it 1.,----- provides for a great surface area for reabsorption of materials. Most of the reabsorption of material in the nephron occurs here. The peri tubular capillaries wrap around the kidney tubules and reabsorb the g.---- filtered material. From the proximal convoluted tubule, the fluid flows into the nephron loop (loop of Henle). The nephron loop takes fluid to the distal convoluted tubule. From here the filtrate flows into a collecting duct. Collecting ~ ducts receive fluid from many nephrons. Label the parts of the ~. h._ nephron and associated structures e.----- and color them in. Each part of the J.------nephron should be colored a different color.
h.-----_ To minor calyx
k. _
b. _
Answer Key: a. Glomerulus, b. Distal convoluted tubule, c. Proximal convoluted tubule, d. Cortex, e. Medulla, f. Arcuate vein, g. Arcuate artery, h. Nephron loop (loop of Henle), I. Nephron, J. Collecting duct, k. Afferent arteriole, I.Efferent arteriole, 1. _ m. Glomerular (Bowman's) capsule