Answer:
4 layers
Step-by-step explanation:
1. The innermost layer is called the mucosa. It is composed of transitional epithelium, which allows the bladder to stretch and expand as it fills with urine. The mucosa also produces mucus to protect the bladder from irritation caused by urine.
2. The submucosa is the layer that lies beneath the mucosa. It contains blood vessels, nerves, and connective tissue. The blood vessels supply oxygen and nutrients to the bladder wall, while the nerves help regulate bladder function.
3. The next layer is the muscularis, which consists of smooth muscle fibers arranged in different orientations. This layer plays a crucial role in the contraction and relaxation of the bladder during urination. When the bladder is full, the muscularis contracts to expel urine from the bladder.
4. The outermost layer is called the adventitia or serosa, depending on the location in the bladder. It is made up of connective tissue and helps protect and support the bladder.
In summary, the urinary bladder has four layers in its wall: mucosa, submucosa, muscularis, and adventitia/serosa. These layers work together to enable the bladder to store and eliminate urine efficiently.