Lecture 30: The Ureters, Bladder and Urethra Flashcards
What is transitional epithelium?
Stratified rounded cells
What happens to transitional epithelium when stretched?
Flattens
What is the function of transitional epithelium?
Protection
Where do the ureters arise?
From each renal pelvis at the hilum
What are ureters?
Slender tubes that carry urine from the kidneys to the bladder
Where do ureters descend?
Retroperitoneally through the abdomen, vertically from the hila
What moves urine to the bladder in ureters?
Peristaltic waves
What are the 3 layers of the ureter?
- Mucosa
- Muscularis
- Adventitia
What makes the mucosa of the ureter?
2
- Transitional epithelium
- Lamina propria
What makes the muscularis of the ureter?
- Inner longitudinal muscle
- Outer circular muscle
What is the adventitia of the ureter?
A fibrous connective tissue
What provides additional protection to the inner surface of the ureter lumen?
Protein plaques
How do ureters run into the bladder?
Oblique through the wall of the bladder at its posterolateral corners
What do ureters act as?
Sphincter/valves
How do uterus act as sphincters/valves?
When compressed by increased bladder pressure to prevent back flow
What is the urinary bladder?
A collapsible muscular sac
What does the urinary bladder store/repel?
Urine
When empty what does the bladder collapse along?
Folds called rugae
What happens to the bladder when it expands?
It does so without great increase in pressure to approximately 500ml
What is the shape of an empty bladder?
Pyramidal
Where does the bladder lie when empty?
Within the pelvis
What happens to the bladders shape as it fills?
It becomes more spherical
Where does the bladder expands as it fills?
Superiorly into the abdominal cavity
What can we do to the bladder when it is full?
Palpitate it above the pelvic symphysis
What is the location of the male bladder?
2
- Anterior to the rectum
- Superior to prostate glands (wraps around the urethra)
What is the location of the female bladder?
Anterior to the vagina and uterus
What is the urinary bladder folded into for expansion?
Rugae
What is the mucosa of the urinary bladder?
Transitional epithelium
What is the name of the thick smooth muscle layer in the urinary bladder?
Detrusor
What is the detrusor made of?
3
- Longitudinal fibres
- Oblique fibres
- Circular fibres
What does the urinary bladder contract to do?
Expel urine from the bladder into the urethra during urination
What is the urethra?
A thin walled muscular tube
What does the urethra do?
Drains urine from the bladder out of the body
What happens to the epithelium along the urethra?
It changes
What are the 3 types of epithelium in the urethra?
- Transitional epithelium (near the bladder)
- Columnar epithelium
- Stratified squamous (near the external opening)
What are there significant difference between the urethras of?
Men and women
How long is the female urethra?
Approximately 5cm
What is the female urethra seperate from?
The reproductive system
How long is the male urethra?
Approximately 25cm
What is the male urethra part of?
The reproductive system
What is the initial section of the urethra surrounded by?
The prostate glands
What does the prostate gland do?
Produces seminal fluid
What are the 3 sections of the urethra?
- Prostatic
- Membranous
- Spongy/penile
What is the internal urethral/urinal sphincter the junction of?
The bladder and urethra
What type of muscle is the internal urethral/urinal sphincter?
Detrusor muscle
What kind of control is the internal urethral/urinal sphincter under?
Involuntary control
Where is the external urethral/urinary sphincter located?
Where the urethra passes through the urogenital diaphragm
What type of muscle is the external urethral/urinal sphincter?
Skeletal muscle
What kind of control is the internal urethral/urinal sphincter under?
Involuntary control
What happens to the bladder in urination?
Fills with urine and expands
When the bladder expands what happens to action potentials?
Action potentials are sent from stretch receptors to the brain
What happens to the urgency of urination as action potential frequency increases?
Urgency increases
What happens to the internal sphincter of the urethra during urination?
It relaxes
What has to happen to the external sphincter of the urethra during urination?
It has to be consciously relaxed
