Lecture 34: Ureters, bladder, and urethra

Question 1

What is the structure of the ureters?

How is urine moved through the ureters to the bladder?

Answer 1

• slender tubes that carry urine from the kidneys to bladder
• arise from each renal pelvis at each hilum
• ureters run vertically down from hilum, descending retropertioneallly through the abdomen.
• ends of tubes close acting as valves when the bladder is full( are compressed by the increased bladder pressure) preventing back flow
  = peristaltic waves move urine through the ureters to the bladder

Question 2

What are the three layers of the ureter?

Answer 2

= Transitional epithelium
= Muscularis: inner longitudinal and outer circular
= Adventitia: outer covering of fibrous connective tissue

Question 3

What is the structure of the urinary bladder:

Answer 3

• Is a muscular sac made from detrusor muscle
• When empty the bladder collapses along folds of rugae
• when full, the bladder expands without great increase in pressure
  Three openings: 2 entry for ureters, 1 for urethra
• Triangular region between the openings is the trigone
• thick layer of detrusor muscle: criss crossing random network of circular, longitudinal and oblique fibres

Question 4

What is the function of the urinary bladder?

Answer 4

The function is to both store and eject urine into the urethra.
- it is a muscular sac that is capable of being inflated and collapsed.
= wall of bladder has same layers as ureters
BUT there is a thick layer of detrusor muscle
- which squeezes urine from bladder during urination

Question 5

What happens when the:

• empty bladder
• as bladder fills

Answer 5

• as the urinary bladder fills it becomes more sphere shaped and expands superiorly upwards into the abdominal cavity
• —> can be palpated above the pubic symphysis
• when the urinary bladder is empty it is a pyramidal shape and lies within the pelvis

Question 6

Where is the bladder loaded in males and females ?

Answer 6

Male
- anterior to rectum and superior to prostate(wraps around urethra)
Female
- anterior to vagina and uterus

Question 7

What is the structure of the urethra?

What is the function?

Answer 7

Is a thin walled muscular tube which drains urine from the bladder and out of the body

• epithelium of the urethra changes: from transitional epithelium near the bladder, to columnar epithelium further on, and finally to stratified squamous epithelium near the external opening
• mucous glands protect epithelium from urine

Question 8

What are the two urethral sphincters?

What is their function?

Answer 8

Internal urethral/urinal sphincter
- is formed by the detrusor muscle at the junction of the urethra and the urinary bladder
- involuntary control = parasympathetic innervation
External urethral/urinary sphincter
- located where the urethra passes through the urogenital diaphragm
- skeletal muscle = voluntary control

Question 9

How does the urethra differ between males and females ?

Answer 9

Female = short (5cm) and separate from reproductive system 
Male = longer (25cm) and part of the reproductive system