Urinary bladder

Definition

The urinary bladder is a muscular sac in the pelvis that stores urine before it is excreted from the body. It plays a crucial role in the elimination of waste and osmoregulation.

5 Must Know Facts For Your Next Test

1. The urinary bladder can hold approximately 400-600 mL of urine in an adult.
2. The detrusor muscle, which forms the wall of the bladder, contracts to expel urine during urination.
3. The internal urethral sphincter and external urethral sphincter control the release of urine from the bladder.
4. Stretch receptors in the bladder wall signal the brain when it is time to urinate.
5. A full bladder triggers a reflex that sends signals to relax the internal urethral sphincter while contracting the detrusor muscle.

Review Questions

• What volume of urine can an adult urinary bladder typically hold?
• Which muscle in the bladder wall is responsible for contraction during urination?
• What role do stretch receptors play in the function of the urinary bladder?

Related terms

Renal Pelvis: The funnel-shaped structure in each kidney where urine collects before moving to the ureter.

Ureter: A tube that carries urine from each kidney to the urinary bladder.

Detrusor Muscle: The smooth muscle layer of the bladder wall responsible for its contraction during urination.