Bladder And Urethra Flashcards
What is the bladder?
A temporary reserve for urine. It can vary in size, shape, relations and position according to its content and the state of neighbouring viscera.
Does the bladder always contain some urine?
Yes, the minimum amount is approximately 50ml.
In adults where does the bladder sit?
The empty bladder sits in the lesser pelvis inferior to the peritoneum. When full, it extends superiorly in the extraperitoneal fat of the anterior body wall.
Where does the bladder sit in infants and children younger than 6.
It sits in the abdomen, even when empty.
What are the three layers of smooth muscle of the wall of the bladder?
An internal, middle and external layer. These form the detrusor muscle.
What are the alignment of the muscle fibres in the three layers of muscle?
The internal and external fibre layers are in a similar longitudinal directional alignment. The middle layer is aligned in a roughly circular direction.
What is bladder musculature?
A distorted continuation of the three layers of spiral smooth muscle that surround the ureters.
What is the trigone?
A smooth triangular area on the posterior wall of the bladder between the ureteric orifices.
What are rugae?
Ridges that line the majority of the empty bladder, flattening out as the bladder fills.
What kind of epithelial is present from the renal pelvis to the urethra?
A specialised epithelium, transitional epithelium or urothelium.
What is special about the bladders epithelium?
The cells have the ability to stretch, shift over one another and flatten. The epithelium of a distended bladder may appear only two to three cells thick whereas in an empty bladder it is usually five to six cells thick.
What’s the structure a non-distended urothelium?
It has a cuboidal base layer, polygonal called middle layers and tall columnar cells in the surface layer.
What is found at the junction between the bladder and urethra?
A smooth muscle sphincter, the internal urethral sphincter, which is controlled by autonomic innervation.
What is the urethra structure?
A continuation of the smooth muscle of the bladder, which also contains a skeletal muscle sphincter, the external urethral sphincter, which is under voluntary control.
What is the urethra?
A muscular-walled tube through which urine is expelled from the bladder during urination.
