Structure and Function of
Urinary System
Aim
Have a greater understanding of
anatomy and physiology of
urinary system
Objectives
Describe the basic structure and
function of the bladder, urethra and
pelvic floor
Outline the differences between
male and female anatomy and
physiology of the urinary system
Anatomy
How much do you know?
Have a go at labelling the diagrams
Requirements for urinary control
A bladder
A sphincter mechanism
A pelvic floor
A nervous system
Cognitive ability
A locomotor ability
Urinary System
Brain
sends messages
to and from the
bladder and bowel
Kidneys
produce urine
Pelvic Floor
muscles which
support the
bladder and bowel
Urethra
tube leading from
the bladder to
outside the body
Spinal Cord
carries the
messages
Ureters
tubes leading
from the
kidneys to
the bladder
Bladder
stores urine
Bowel
stores faeces
Function of the bladder
Dual purpose
storage phase
emptying phase
Bladder capacity
500 mls
1st desire to void
250 mls
How Much Will an Adult Bladder
Hold?
100-150mls
150-200mls
350mls
200-450mls
450-600mls
sensation of filling
1st desire to void
2nd desire to void
toleration without undue discomfort
experience discomfort
A full bladder will hold 400 – 600 mls approx
Normal Bladder Function
Detrusor relaxed
1. Filling and Storage Stage
Bladder neck closed
Internal sphincter contracted
2. Voiding Phase
Bladder neck opens
External sphincter
& pelvic floor relaxed
Urine expelled
3. Termination of Voiding
Any remaining urine is
squeezed back into the
bladder by the sphincter
Bladder neck closed
External sphincter &
pelvic floor contract
The Male Urethra
18cms in length
S shaped passageway for:
Urine
Semen
Prostatic secretions
Smooth muscle contraction causes
compression that maintains
continence
The Female Urethra
Differs considerably from the male
Straight
3-5 cms in length
Passes through levator ani muscles
of pelvic floor
The Pelvic Floor
Supports the pelvic organs
Contraction causes urethral
compression, helping to maintain continence
Collectively called the ‘levator ani’
Striated muscle - slow and fast muscle fibres
under voluntary control
Any Questions?