Lecture Notes: Urinary System and Bladder Function

Introduction

Topic: Exploring whether the bladder can explode if you hold in urine too long.
Background Story: Childhood experience with sisters locking out, leading to the inquiry about bladder bursting.

Kidney Function:
- Filtration: Filters blood and adjusts hydration levels.
- Structure:
  - Renal Cortex: Contains filtration units.
  - Renal Pyramids: Transport waste to urinary tract.
  - Ureter: Long tube carrying urine to the bladder.
Urinary Bladder:
- Function: Storage organ for urine.
- Capacity: Normally holds 400-500 ml, max 1 liter.
- Convenience Organ: Not necessary but helps mark territory.
Urethra:
- Function: Evacuates urine from bladder.
- Structure: Differs in length between male and female.

Micturition Reflex (Desire to Urinate):
- Transitional Epithelium: Stretches with urine volume.
- Detrusor Muscle: Smooth muscle, involuntary contraction.
- Sphincters:
  - Internal Urethral Sphincter: Involuntary.
  - External Urethral Sphincter: Voluntary.
Neural Control:
- Stretch Receptor Neurons: Monitor urine volume.
- Signal Pathways: Include spinal cord and brain centers (pons, prefrontal cortex).
- Decision Making: When and how to urinate managed by neural signals.

Can the Bladder Rupture?
- Yes, but Rarely: Only with pre-existing conditions.
- Types of Ruptures:
  - Intraperitoneal: Urine reabsorbed, requires surgery.
  - Extraperitoneal: Easier management with catheter.
Causes of Rupture:
- Trauma: e.g., automobile accidents.
- Medical Conditions: e.g., bladder cancer.
- Other: e.g., improper catheter use.
Holding Urine: Unlikely to cause rupture, more likely to lead to involuntary urination.