Lecture 30: The Ureters, Bladder and Urethra

Question 1

What is transitional epithelium?

Answer 1

Stratified, rounded cells that flatten when stretched

Question 2

What is the purpose of transitional epithelium?

Answer 2

for protection by making a barrier to stop urine leaking through

Question 3

What are the ureters?

Answer 3

slender tubes that carry urine from the kidneys to the bladder

Question 4

Ureters arise from each _______ _______ at each _________

Answer 4

renal pelvis

hilum

Question 5

Ureters descend where?

Answer 5

retroperitoneally through the abdomen, vertically from each hilum

Question 6

What allows urine to move to the bladder?

Answer 6

peristaltic waves in the ureter

Question 7

What are the three layers of the ureters?

Answer 7

• transitional epithelium on the lamina propria
• muscularis
• adventitia

Question 8

Describe the muscularis in the ureter

Answer 8

inner longitudinal, outer circular

Question 9

Describe the adventitia of the ureter

Answer 9

an outer covering of fibrous connective tissue

Question 10

What sits on the surface of the transitional epithelium in the ureter?

Answer 10

folded protective protein plaques

Question 11

What is the advantage of having inner longitudinal and outer circular muscle instead of the other way around?

Answer 11

We don’t want any urine flowing backward back to the kidney so when the outer circular contracts to close over the tube, if there was no longitudinal in the middle, there would always be a little lumen but with both, it would close

Question 12

How do the ureters enter the bladder?

Answer 12

they run obliquely through the wall of the bladder at its posterolateral corners

Question 13

What is the advantage to the ureters entering the bladder at an oblique angle?

Answer 13

it acts as a sphinctor/valve compressed by the increased bladder pressure to prevent backflow

Question 14

What is the urinary bladder?

Answer 14

a collapsible muscular sac which stores and expels urine

Question 15

What is a feature of the bladder that allows it to expand to accomodate an increased volume?

Answer 15

rugae

Question 16

What is the bladder wall made of?

Answer 16

detrusor muscle for the expulsion of urine

Question 17

What is the trigone?

Answer 17

it is the triangular region of the bladder with three openings - one for each of the the two ureters and one for the urethra

Question 18

What does an empty bladder look like and where does it lie?

Answer 18

it is pyramidal and it lies within the pelvis

Question 19

What happens as the bladder fills?

Answer 19

is becomes more spherical and expands superiorly into the abdominal cavity

Question 20

Where is the bladder located in males and how does this differ to the position in females?

Answer 20

• males: anterior to the rectum, superior to the prostate gland (it wraps around the urethra)
• females: anterior to the vagina and uterus

Question 21

What is the mucosa of the bladder?

Answer 21

• transitional epithelium (with protein plaques closest to the lumen)

Question 22

What is the detrusor muscle of the bladder made of?

Answer 22

• longitudinal, circular and oblique fibres

Question 23

What do contractions of the detrusor muscles of the bladder cause?

Answer 23

expulsion of urine into the urethra during urination

Question 24

What is the urethra?

Answer 24

the thin walled muscular tube that drains urine out of the body

Question 25

The epithelium changes along the urethra. What are they are where are they?

Answer 25

• transitional epithelium near the bladder
• columnar
• stratified squamous near the external opening

Question 26

What glands are present in the urethra and why are they needed?

Answer 26

mucous glands secrete mucous to protect the epithelium from the urine

Question 27

How do the male and female urethra differ?

Answer 27

• females is much shorter and is separate from the reproductive system whereas males is longer and part of the reproductive system
• males have three sections with the initial section surrounded by prostate gland

Question 28

What are the three sections of the male urethra?

Answer 28

• prostate
• membranous
• spongy/penile

Question 29

What are the two sphincters of the bladder?

Answer 29

• internal urethra/urinary sphincter

- external urethral/urinary sphincter

Question 30

Where is the internal urethra/urinary sphincter?

Answer 30

at the junction between the bladder and urethra

Question 31

Is the internal urethra/urinary sphincter under voluntary or involuntary control? Which muscle is it controlled by?

Answer 31

involuntary

controlled by the detrusor muscle

Question 32

Where is the external urethra/urinary sphincter?

Answer 32

where the urethra passes through the urogenital diaphragm

Question 33

Is the external urethra/urinary sphincter under voluntary or involuntary control? Which muscle is it controlled by?

Answer 33

voluntary

controlled by skeletal muscles

Question 34

What are the 5 steps to urination?

Answer 34

1. the bladder fills with urine and expands
2. AP from stretch receptors alert the brain
3. urgency increases as the signals increase
4. internal sphincter relaxed
5. conscious relaxation of the external sphincter