Which Type Of Epithelium Lines The Interior Of The Urinary Bladder?
From the inside out, the microscopic structure of the urinary bladder wall consists of the following layers. Embryonic epithelium Lamina propria Muscularis propria Serosa/Adventitia The lining epithelium of the urinary bladder is urothelium, a specialized stratified epithelium.
The urothelium is found solely in urinary structures, including the ureter, urinary bladder, and proximal urethra. The urothelium consists of three distinct layers: Apical layer – The deepest layer functions as a barrier between the bladder lumen and the tissue underneath it. It is a single layer of usually binucleated umbrella-shaped (i.e., umbrella cells) cells.
These apical umbrella cells of the urothelium create an impermeable barrier; strong connections between the cells reduce paracellular flow, and a glycoprotein coating of uroplakin covers the umbrella cells to form a surface plaque. Two to three layers of polygonal cells compose the intermediate layer.
- Two to three layers of cuboidal cells compose the basal layer.
- The urothelium of a relaxed urine bladder consists of five to seven layers.
- When urine fills the urinary bladder, the bladder wall extends to accommodate the increased volume.
- The urothelium in the enlarged bladder reorganizes into two or three layers without structural harm.
Due of the urothelium’s capacity to transition, it is sometimes referred to as the transitional epithelium. Lamina Propria: This is the suburothelial layer that separates the urothelium from the suburothelial muscularis propria (detrusor muscle). Basement membrane separates it from the overlaying urothelium.
Composed of elastic fibers, capillaries, lymphatics, immune cells, afferent and efferent nerve endings, fibroblasts, myofibroblasts, adipocytes, interstitial cells of Cajal or telocytes, an indistinct smooth muscle layer, and the muscularis mucosae, its extracellular matrix also contains capillaries, lymphatics, immune cells, afferent and efferent nerve endings, fibro Within the lamina propria, the interstitial cells of Cajal create a syncytium with the smooth muscle cells and nerve terminals.
It is believed that the interstitial cells of Cajal serve as pacemaker cells in the gastrointestinal tract, urethra, and prostate. They appear to function as nerve signal transducers to smooth muscle cells in the bladder. Muscularis propria: It consists of three layers: inner longitudinal, middle circular, and outer longitudinal.
- It is also known as the detrusor muscle.
- Around the neck of the urinary bladder, these layers are well-defined; however, throughout the rest of the bladder wall, they are disorganized and random.
- The body of the bladder has more smooth muscle than the trigone, indicating a well-developed network of myofibroblasts in the lamina propria and muscularis mucosae.
This thin layer of connective tissue covers the bladder dome and connects to the peritoneal layer of the abdominal wall. Also there are blood vessels of varying diameters. Adventitia: This layer of loose connective tissue acts as the outer layer of the bladder in locations without serosa.
What is the most prevalent form of bladder epithelium?
Function-based categorization of epithelial cells – Epithelial cells can also be classified according to their particular roles, such as: A transitional epithelium, commonly known as urothelium, consists of many layers of cells that flatten when stretched.
It lines the majority of your urinary tract and enables the expansion of your bladder. This sort of epithelium is specialized for producing and secreting (releasing) chemicals. Your glands are specialized organs that may produce, store, and/or release chemicals like hormones, proteins, and water. Olfactory epithelium: Located in the nasal cavity, the olfactory epithelium comprises olfactory receptor cells with specific cilia extensions.
When odor molecules move over the epithelium surface, the cilia catch them. The receptors communicate information about the chemicals to the olfactory bulb in the brain, which analyzes the odor.
Similar to the cuboidal sub-type, stratified columnar epithelium is exceedingly uncommon. It is situated in the conjunctiva within the eyelids and transition zones of tissue. It is primarily responsible for defense and mucus production.
Where is stratified cuboidal epithelium found?
Stratified Cuboidal Epithelium – Both stratified cuboidal and stratified columnar epithelia are extremely uncommon. In the excretory ducts of sweat and salivary glands, stratified cuboidal epithelium is present. They are also present in mammary glands and ovarian follicles in development.