Renal and Urinary Physiology 3 Flashcards
What happens when urine production ends?
Fluids enter the renal pelvis
What are the ureters?
6
A pair of muscular tubes
Extend from kidneys to urinary bladder
Begin at renal pelvis
Penetrate the posterior wall of the urinary bladder
Pass through bladder wall at oblique angle
Ureteral openings are slit-like rather than rounded
Why are the ureteral openings slit like and not rounded?
It helps prevent the backflow of urine when the urinary bladder contracts
What makes up the histology of the ureter?
3
Inner mucosa
Middle muscular layer
Outer connective tissue layer
What makes up the inner mucosa?
2
Transitional epithelium
Lamina propria
What makes up the middle muscular layer?
2
Longitudinal smooth muscle
Circular bands of smooth muscle
What moves urine towards the bladder?
Peristaltic contractions
Describe peristaltic contractions that move urine
4
Begin at renal pelvis
Sweep along ureter
Force urine toward urinary bladder
Every 30 seconds
What is the urinary bladder?
3
A hollow, muscular organ
Functions as temporary reservoir for urine storage
Can contain 1 litre of urine when full
What stabilises the bladder?
Several peritoneal folds
What anchors the urinary bladder to pelvic and pubic bones?
Ligamentous bands
What do the ligamentous bands do?
They anchor the urinary bladder to the pelvic and pubic bones
What are the folds in the bladder called?
Rugae
What is the trigone?
2
The triangular area of the bladder
It acts as a funnel
What is the neck of the bladder?
2
The region surrounding the urethral opening
It contains a muscular internal urethral sphincter
What does the internal urethral sphincter do?
It provides involuntary control of urine discharge
What provides involuntary control of urinary discharge?
Smooth muscle fibres
What is the bladder histology made of?
3
Mucosa
Submucosa
Muscularis layers
What is the mucosa of the bladder made of?
Transitional epithelium
What is the muscularis layer made of?
2
Detrusor muscle
Inner and outer layers of longitudinal smooth muscle with a circular layer in between
From where does the urethra extend?
It extends from the neck of urinary bladder to the exterior of the body
What is the external urethral sphincter?
6
A circular band of skeletal muscle
Acts as a valve
Its under voluntary control
Has resting muscle tone
Voluntary relaxation permits micturition
Write a note on the histology of the urethra.
Lamina propria
Mucous membrane
Mucin-secreting cells
Stratified squamous epithelium
Describe the lamina propria of the urethra.
Thick and elastic
Describe the mucous membrane of the uretha.
Has longitudinal folds
Where are the mucin-secreting cells of the urethra found?
They lie in epithelial pockets
How does the urinary system change with aging?
4
The number of functional nephrons declines
Glomerular filtration rate is reduced
Reduced sensitivity to antidiuretic hormone
Problems with the micturition reflex
