Lecture 23, 24 & 25: Urinary Bladder &Micturition, UTI & Overactive bladder Flashcards
(103 cards)
What is the function of the bladder?
- A temporary storage of urine that can empty at an appropriate time
Where is the bladder situated when empty and when full?
- In the pelvic cavity
- Partly in pelvic cavity but expands superiorly into abdominal cavity
At what age does the bladder descend into the pelvis area from the abdominal area?
- By the 5th or 6th age
- It is an abdominal organ at birth and positioned in extraperitoneal area of lower abdominal wall
What are the 4 parts of the urinary bladder?
- Apex
- Base
- Superior surface
- Inferolateral surface
What is the mucosal lining of the base of the bladder like?
- Smooth firmly attached to the muscle coat of the wall
What are some features that make up urinary bladder anatomy and what are the functions?
- Ureter: Tubes that transport urine from kidney to bladder
- Internal and external sphincters: Controls release and prevents leakage
- Urethra: Tube that carries urine from bladder outside of body
What is the mucosal lining of the bladder like elsewhere besides the base?
- Folded and loosely attached to the wall
What is the trigone?
- The smooth triangular area between the openings of the ureters and urethra inside of the bladder
What are the 4 muscle/membrane layers of the bladder?
- Mucosa: inner layer
- Submucosa: connective tissue
- Detrusor muscle: muscular layer
- Adventitia/Serosa: Covers most of bladder/membrane that covers top part of bladder
What is the main difference between a male and female’s bladder and urethra?
- Males have internal and external urethra sphincter and is longer
- Females only have external one and is shorter and more prone to UTI
What does the sympathetic nerve do to the bladder?
- Transmit impulses from the pain receptors to the upper lumbar segment resulting in perception of pain sensation from the urethra and bladder
- Involves hypogastric nerve
What does the pelvic (parasympathetic) nerve do to the bladder?
- Transmit impulses from the tension and pain receptors present in the wall of the bladder to the sacral region of spinal cord resulting in both reflex micturition and sensation of bladder fullness
- Under Ach
What does the Pudendal (somatic) nerve do to the bladder?
- Transmit impulses for the sensation of:
- Distension of urethra
- Passage of urine through urethra
- Maintains the tonic contractions of the skeletal muscle fibres of the external sphincter
- Voluntary control
How does the pelvic nerve work?
- Releases Ach and binds to the M3 receptor of Detrusor muscle on the bladder to cause muscle contractions to force urine out
How does the sympathetic nerve work?
- Releases noradrenaline at the bladder beta 3 receptors in detrusor muscles and urethra alpha receptor 3 in to:
1. Inhibit contraction of the bladder then release NA for A3
2. Stimulate contraction of the urethra: fill w/ urine - Both to prevent urine release
How does the Pudendal (somatic) nerve work?
- Releases Ach at the nicotinic receptors of the external urethral sphincter to cause contraction hence preventing urine release
Which fibres supply the sympathetic system in the bladder?
- The preganglionic fibres which branch from the upper 4 lumbar vertebrae
- The postganglionic fibres arise from the hypogastric ganglia
What are the functions of the sympathetic nerves?
- Inhibitory to the bladder wall (detrusor muscle)
- Motor to the internal urethral sphincter
- Motor to the seminal vesicle, ejaculatory duct & prostatic musculature. It prevents reflux of semen into bladder
What fibres supply the parasympathetic system in the bladder?
- The preganglionic fibres from the 2nd, 3rd and 4th sacral segments of the vertebrae
- They Form the pelvic nerve which relays in the terminal ganglia embedded in the wall of the urinary bladder
What are the functions of the parasympathetic nerves?
- Motor to the bladder wall (detrusor muscle)
- Inhibitory to the internal urethral sphincter
What fibres supply the somatic system in the bladder?
- Arise from 2nd,3rd and 4th sacral segments and supplies the external urethral sphincter
What is the function of the somatic supply?
- Motor to the external urethral sphincter
When does the micturition reflex start to happen?
- From stage 1 when the bladder reaches 150-300ml
- So the early stage of feeling the urge to urinate
At what point can micturition no longer be suppressed?
- At about 700ml (break point)
- Feel pain