The urothelium is exclusively in urinary structures such as the ureter, urinary bladder, and proximal urethra. The urothelium is composed of three layers: Apical layer – The innermost layer serves as a barrier between the bladder lumen and the underlying tissue.
How does the barrier function of the urothelium?
- 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).
- 1 What allows lining of bladder to stretch?
- 2 Which kind of epithelium allows for stretching?
- 3 What allows transitional epithelium stretching?
- 4 What is special about the urothelium?
- 5 What structures are lined by urothelium?
- 6 What is the urothelium?
- 7 What type of epithelium has flattened cells?
- 8 What type of tissue can stretch?
- 9 What type of epithelium is urothelium?
- 10 Why transitional epithelium is called urothelium?
- 11 Why the cells are in transitional epithelium differ in shape and can be stretch at certain extent?
- 12 What is the difference between relaxed and stretched epithelium?
- 13 How is the urothelium adapted to its function?
- 14 Where does urothelium end?
- 15 What is transitional epithelium function?
What allows lining of bladder to stretch?
Transitional epithelium, elastic fibers, and visceral muscle tissue in the walls of the urinary bladder contribute to its distensibility and elasticity, allowing it to easily stretch and return to its original size several times each day.
Which kind of epithelium allows for stretching?
The epithelial tissue type that has the specific ability to stretch is the transitional epithelium, which resembles both stratified squamous and
What allows transitional epithelium stretching?
The transitional epithelium usually appear cuboidal when relaxed and squamous when stretched. This tissue consists of multiple layers of epithelial cells which can contract and expand in order to adapt to the degree of distension needed.
What is special about the urothelium?
The urothelium, the epithelium lining the surface of the urinary bladder, is a unique cell type with high plasticity and a variety of cellular functions. The urothelium represents the first line of bladder defense and an interface between pathogens and defense mechanisms.
What structures are lined by 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 is the urothelium?
Listen to pronunciation. (yoo-roh-THEE-lee-um) The lining of the urinary tract, including the renal pelvis, ureters, bladder, and urethra.
What type of epithelium has flattened cells?
Simple squamous epithelium consists of thin, flattened cells, that are one layer thick and allow for the easy movement of substances.
What type of tissue can stretch?
Muscle tissue. Muscle tissue is both extensible and elastic, in other words, it can be stretched and returned to its original size and shape. The cells of muscle tissue are unique in that they are contractile, or capable of contraction.
What type of epithelium is urothelium?
The urothelium is a transitional epithelium, classified as such because its properties lie between stratified squamous and simple non-stratified epithelia.
Why transitional epithelium is called urothelium?
The transitional epithelium is also called urothelium because it lines urinary ducts, such as renal calyxes (2 cell layers), urethers (3 to 5 cell layers), urethra (4 to 5 cell layers) and urinary bladder (up to 6 cell layers). These cells form the impermeable barrier to diffusion between urine and blood.
Why the cells are in transitional epithelium differ in shape and can be stretch at certain extent?
Transitional epithelium is a stratified tissue made of multiple cell layers, where the cells constituting the tissue can change shape depending on the distention in the organ. When the organ is filled with fluid, cells on the topmost layer of this epithelium can stretch and appear flattened.
What is the difference between relaxed and stretched epithelium?
The layer of tissue just underneath the epithelium is connective tissue, and at the bottom of the image you can see some smooth muscle tissue. The image shows the wall of the urinary bladder in the relaxed state (not distended). When the tissue is stretched, the cells, especially those on the surface, become flat.
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. Responsive, rather than constitutive, programme of cell proliferation and tissue regeneration.
Where does urothelium end?
Distal to the proximal urethra is the membranous urethra, a segment in which the urothelium is replaced by a stratified columnar epithelium. This same epithelium extends into the spongy urethra, eventually transitioning to a nonkeratinizing stratified squamous epithelium at the end of the urethra.
What is transitional epithelium function?
The cells of the transitional epithelia are specialized to protect underlying tissues from the hypertonic and potentially cytotoxic effects of urine. The morphological features of the cells allow distension of transitional epithelium as the urinary bladder fills and stretches.