Lecture 33 Flashcards
What type of epithelium is found in most the urinary tract?
Transitional epithelium
What is transitional epithelium?
Stratified, rounded epithelial cells that flatten when stretched
What is the function of transitional epithelium?
Protection
How many ureters are there?
Two
What are the ureters?
Slender tube structures that arise from each renal pelvis at each hilum and carry urine from the kidneys to the bladder
Where do the ureters lie?
Retroperitoneally
What moves urine to the bladder?
Peristaltic waves
What are the three layers of the ureter wall?
Mucosa, muscularis, adventitia
What is the mucosa composed of?
Lamina propria and transitional epithelium
What does the mucosa of the ureters secrete?
Protein plaque
What is a protein plaque?
A waxy substance that sits along the inner surface of the ureter to create a double layer of protection
What is the composition of the muscularis in the ureters?
Inner longitudinal, outer circular
How do the ureters enter the bladder?
On an oblique angle through the wall at its posterolateral corners
What does the oblique angle act as?
A sphincter/valve that is compressed by increased bladder pressure to prevent backflow
What is the urinary bladder?
A collapsible muscular sac that stores and expels urine
What happens to the bladder when it is empty?
It lies within the pelvis, collapses along the rugae and is a pyramidal shape
What happens to the bladder when it is full?
It becomes a spherical shape and can be palpated above the pubic symphysis
What happens to the bladder when it is filling?
It expands without a great increase in pressure (~500mL) superiorly into the abdominal cavity
What is the location of the male urinary bladder?
Anterior to the rectum, superior to the prostate gland which wraps around the urethra
What is the location of the female urinary bladder?
Anterior to the vagina and uterus
Where are the rugae of the urinary bladder?
In the mucosa of transitional epithelium
What is the muscle of the urinary bladder called?
Detrusor
What is the composition and function of muscle in the urinary bladder?
Longitudinal, circular and oblique fibres in no distinct layer only function is to contract and expel urine
What is the urethra?
A thin-walled tube that drains urine from the bladder, out of the body
What are the epithelial changes along the urethra?
Transitional epithelium near the bladder, columnar between and then stratified squamose near the external opening. Also containing mucus glands for protection
What is the length of the female urethra?
~5cm
What is the length of the male urethra?
~25cm
What is the difference between the male and female urethra?
Male is apart of the reproductive system, female is not
What are the three sections of the male urethra?
Prostatic, membranous and penile (spongy)
How many urethral sphincters are there?
Two; internal and external
What is the internal urethral sphincter?
Detrusor muscle so under involuntary control, at the junction of the bladder and urethra
What is the external urethral sphincter?
Skeletal muscle so under voluntary control, located where the urethra passes through the urogenital diaphragm
Explain urination
The bladder fills and expands, APs sent from stretch receptors to the brain, urgency increases and signals increase. This causes the internal sphincter to relax and a conscious decision is made to relax the external sphincter
