Special Surgical Procedures II
LESSON 3: Procedures in Genitourinary Surgery
Section I: ANATOMY AND PHYSIOLOGY OF THE GENITOURINARY ORGANS
3-4
3-4. URINARY BLADDER
a. The urinary bladder (see figure 3-5) is a musculomembranous sac situated in the pelvic cavity behind and below the symphysis pubis, in front of the rectum, and above the prostate gland in the male. The bladder lies in front of the neck of the uterus and the anterior wall of the vagina in the female. When the bladder becomes full and distended, it begins to ascend above the symphysis pubis, pushes its peritoneal covering ahead of it, and partially becomes an abdominal structure.
b. The bladder is connected to the pelvic wall by fascial attachments that extend from the back of the pubic bones to the front of the bladder. Other muscular fibers also pass from the base of the bladder to the sides of the rectum.
c. The bladder consists of a thick muscular wall with outer adventitial and inner mucosal layers. In addition, a peritoneal layer partially covers and is attached to the bladder dome. The blood supply of the bladder is derived from branches of the anterior trunk of the hypogastric artery.
d. As a result of the peristaltic muscular contraction of the renal pelvis and ureter, the urine is actively propelled from the kidney to the bladder and expressed from the ureteral orifice.
e. The size, position, and relation of the bladder to the intestines, rectum, and reproductive organs vary according to the amount of fluid it contains. The process of emptying the bladder appears to be initiated by nerve cells from the sacral divisions of the autonomic nervous system. These sacral reflex centers are controlled by higher voluntary centers in the brain. Stimulation from the sacral centers results in contraction of the bladder muscle and relaxation of the bladder outlet sphincters. Muscle tone maintains closure of the sphincters when the bladder is at rest.
