This lesson follows urine from the kidneys to the bladder and explains how the bladder stores urine and coordinates its release. Understanding these structures and their control helps explain normal urination and problems such as urinary reflux or incontinence.
Urine drains from the kidney’s calyces into the renal pelvis, a funnel-shaped collecting region in the kidney hilum. The renal pelvis narrows into a ureter, which carries urine to the bladder. The kidneys and ureters are retroperitoneal; the bladder has a peritoneal covering only over its dome.
All flashcards
What is the detrusor muscle?
The bladder’s smooth muscle, arranged in irregular bands, that contracts to help empty the bladder.
How does the ureter’s passage through the bladder wall help limit backflow?
Its oblique course acts as a physiological one-way valve, allowing urine to enter the bladder while helping prevent reflux.
What initiates the micturition reflex?
Bladder stretch receptors send afferent signals to the sacral spinal cord.
What are the roles of the hypogastric, pelvic, and pudendal nerves in urination?
Hypogastric sympathetic activity supports storage; pelvic pathways help trigger emptying; the pudendal nerve enables voluntary control of the external sphincter.
What do bulbourethral glands contribute to the male urethra?
They secrete mucus that lubricates the urethra and helps buffer its usually acidic environment.
Quiz questions
Which sequence lists the four regions of the male urethra from the bladder toward the external opening?Answer: Preprostatic, prostatic, membranous, and spongy.
Why does the shorter female urethra contribute to a higher incidence of urinary tract infections?Answer: It provides a shorter route for bacteria from the fecal region to reach the urinary tract.
Which statement correctly contrasts the internal and external urethral sphincters?Answer: The internal sphincter is involuntary smooth muscle; the external sphincter is voluntarily controlled skeletal muscle.
What is the function of the bulbourethral glands during sexual stimulation?Answer: They release mucus into the urethra to lubricate and help buffer the passage.
Which openings mark the three points of the bladder trigone?Answer: The two ureteral openings and the urethral opening.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.