Bladder And Urethra Flashcards
How much liquid can the bladder hold?
400-500mls
What ligament holds the neck of the bladder in place?
Puboprostatic ligament in men
Pubovesicular ligament in women
What ligament extends from the top of the bladder?
The median umbilical ligament
What are the three layers of muscle found in the detrusor muscle?
Longitudinal (outer)
Circular
Spiral (inner)
What factors contribute to internal urethral closure?
Muscular occulsion by rhabdosphincter Transmission of abdominal pressure to proximal urethra Mucosal surface tension Anatomical configuration at bladder neck Submucosal vascular plexus Elasticity and length of urethra
Do women have an internal urethral sphincter?
No anatomically, but they do have a physiogical mechanism
What’s the venous drainage for the bladder?
A rich venous plexus that drains the the internal iliac veins
Where does the lymphatic drainage for the bladder drain to?
Vesical, external iliac, internal iliac and common iliac lymph nodes
What receptors play a role in micturition?
Muscarinic (M3) and B3 receptors on the detrusor muscle
Alpha-1 receptor found on the internal urethral sphincter
Nicotinic content receptor on the external urethral sphincter
Which parts of the CNS are used during micturition?
Sacaral and thoracic nuclei
Pontine and micturition centres in the brain
Name the three efferent nerves and which nerve fibres they contain.
From the sacral region arises the pudendal nerve, which contains somatic nerve fibres
From the sacral region arises the pelvic nerve, which contains sympathetic nerve fibres
From the thoracic region arises the hypogastric nerve, which contains parasympathetic nerve fibres
What hormone does the pelvic nerve release, which receptor does it bind to and what does it stimulate?
It releases ACh, which binds to the M3 receptor and stimulates contraction of the detrusor muscle
What hormone does the hypogastric nerve release, which receptor does it bind to and what does it stimulate?
The hypogastric nerve releases noradrenaline, which binds to two receptors
- the B3 receptor stimulating the relaxation of the detrusor muscle
- the alpha-1 receptors, stimulating the contraction of the internal urethral sphincter
What happens to the hypogastric nerve on the way to the bladder (why does it release noradrenaline, not ACh)?
It synapses with a ganglion, ACh is released from the pre-ganglionic fibres to stimulate the post-ganglionic fibres, which continue on the the bladder and release the post-ganglionic hormone NA.
What hormone does the puedendal nerve release, which receptor does it bind to and what does it stimulate?
The puedendal nerve releases ACh which binds to the Nicotinic receptor, stimulating the external urethral sphincter