Micturition Flashcards
What is the ureter made up of?
Layers of muscle surrounded by transitional epithelium
What happens when urine enters the ureter?
Distends it and smooth muscles around it contracts
What is the frequency of peristaltic waves in the ureter?
1-6 contractions per minute
What controls the uretal peristaltic waves?
Myogenic nerves (NOT CNS)
How does the ureter open into the bladder?
Obliquely
What does the oblique opening of ureters do?
Prevents reflux of urine back into the ureters by a passive flap valve effect?
How much urine can the bladder hold without much increase in pressure?
400ml
What does the spherical structure of the bladder mean?
Pressure spreads equally all over it
What is the internal sphincter of the bladder made up of?
It’s an extension of the detrusor muscle
Is the internal sphincter under voluntary control?
No
What is the external sphincter made up of?
Two striated muscles (compressor urethrae and bulbocavernosus)
What is the external sphincter responsible for?
Continence
Is the external sphincter under voluntary control?
Yes
What length is the female urethra?
Short
What does the male urethra carry?
Urine and semen
What is urine elimination aided by in males?
Contraction of the bulbocavernosus muscles in penis
Which sex is more prone to incontinence?
Females as the external sphincter is less well developed
What is the lining of the bladder made of?
Transitional epithelium
What type of muscle is the bladder made up of?
Detrusor muscle
Does the composition of urine change in the urinary bladder?
No
What is the bladder permeable to?
Lipophilic molecules
What is the bladder impermeable to?
Salt and water
What is the technical name for kidney stones?
Renal calculi
Where can renal calculi form?
Anywhere along the urinary tract