What is the function of urothelium?
What is the function of urothelium?
The urothelium represents the first line of bladder defense and an interface between pathogens and defense mechanisms. Functions of the urothelium include control of permeability, immune responses and cell-cell communication, which seems to play a pivotal role in responding to injuries and infections.
Which part of the brain are involved in nervous control of micturition?
The micturition reflex is a bladder-to-bladder contraction reflex for which the reflex center is located in the rostral pontine tegmentum (pontine micturition center: PMC). There are two afferent pathways from the bladder to the brain. One is the dorsal system and the other is the spinothalamic tract.
Which structures are lined with urothelium?
Lining epithelium: The urinary bladder lining is a specialized stratified epithelium, the urothelium. The urothelium is exclusively in urinary structures such as the ureter, urinary bladder, and proximal urethra.
What triggers the micturition reflex?
When the bladder is full of urine, stretch receptors in the bladder wall trigger the micturition reflex. The detrusor muscle that surrounds the bladder contracts. The internal urethral sphincter relaxes, allowing for urine to pass out of the bladder into the urethra. Both of these reactions are involuntary.
How is the urothelium adapted to its function?
The urothelium is adapted as a barrier epithelium through: Specialised features that limit transcellular and paracellular permeability. Longevity of superficial urothelial cells to preserve urinary barrier function. High threshold for apoptosis – where cell repair rather than loss is the default pathway.
What is a urothelium definition?
(yoo-roh-THEE-lee-um) The lining of the urinary tract, including the renal pelvis, ureters, bladder, and urethra.
What is the difference between micturition and urination?
micturition: Also known as urination, this is the ejection of urine from the urinary bladder through the urethra to the outside of the body. urine: A liquid excrement consisting of water, salts, and urea that is made in the kidneys then released through the urethra.
What happens in micturition reflex?
The micturition reflex involves a coordinated and sustained contraction of the detrusor muscle (the detrusor reflex) along with simultaneous relaxation of the urethra. Moreover, depending on the size of the bladder, the micturition reflex may also result in urine storage.
What kind of tissue is urothelium?
stratified epithelium
Transitional epithelium also known as urothelium is a type of stratified epithelium. Transitional epithelium is a type of tissue that changes shape in response to stretching (stretchable epithelium).
How is the urothelium adapted for its function?
What is the urothelium of a rodent?
The urothelium is a unique, highly specialized epithelium lining the lower urinary tract. It has a variable number of cell layers, but in the rodent urinary bladder it is usually three cell layers thick in the urinary bladder and more in the ureter.
Does the urothelium have a barrier function?
Contributing to the barrier function of the urothelium is a circumferential band of tight junctions between superficial cells. By scanning electron microscopy (SEM), the luminal surface of the bladder is seen as being composed of hexagonal, large, flattened cells, with an interwoven micro-ridge system on the luminal surface ( Figure 48.6 ).
What is the urothelium of the bladder?
The urothelium is the membrane lining the interior of almost the entire urinary tract from kidneys to proximal urethra. The vast majority of bladder tumors arise in the urothelium. In developed countries, approximately 90% of primary bladder cancer is urothelial.
How many cell layers are in the urothelium of a dog?
It has a variable number of cell layers, but in the rodent urinary bladder it is usually three cell layers thick in the urinary bladder and more in the ureter. In larger mammals, such as dogs, monkeys, and humans, the urothelium frequently has more than three layers, occasionally up to ten or more (Figure 48.3 ).
