Bladder: Cell Types Composing the Tissue

Urinary Bladder

The hollow muscular organ in the pelvic area is known as the urinary bladder. It is spherical in shape and is approximately the size of a large grapefruit. The function of the urinary bladder is to collect and store the urine. The urinary bladder is connected to the kidneys by means of small tubular structures known as ureters. The base of the bladder is connected to the urethra, which helps in draining the urine.

Bladder Anatomy

The sphincter muscle coats the wall of the bladder and prevents leakage of fluid from the bladder. When the bladder is filled, the sphincter relaxes and the bladder contracts, thus emptying the urine.

Various Bladder Tissue Types

• A smooth glistening tissue lines the inner surface of the bladder. This tissue is known as the mucosa and it is made up of transitional epithelial cells in a layer known as the urothelium.
• A layer of connective tissue, nerves, and blood vessels form the layer next to the urothelium.
• Next to this layer is the muscular bladder wall, which is formed by a layer of smooth muscle cells. The primary function of the muscular layer is to contract the bladder to excrete the stored urine. This layer is called the muscularis propria.
• This layer of muscle cells is surrounded by the outermost layer of fat.

The transitional epithelial cells that line the interior of the bladder can transform into cancerous cells, thus leading to bladder cancer.

Bladder Dysfunctions and Cancers

About 90% of bladder cancers are derived from the transitional epithelial cells. The cancer type is determined based on the appearance of the cells.

Types of Bladder Cancers

• 1.
  Transitional cell carcinoma: This is the most common type of bladder cancer, and the cells of this type of cancer resemble those of urothelial cells. About 90% of bladder cancers in the United States are of this type. Transitional cell carcinoma can be either invasive or noninvasive.
• 2.
  Squamous cell carcinoma: The cells of this cancer appear like the flat cells on the surface of the skin. Only 1% to 2% of the bladder cancers in the United States are of this type. These are mostly invasive.
• 3.
  Small cell carcinoma: These types of cancer account only for 1% of the bladder cancers in the United States. The cells of this type of cancer appear like nerve cells.
• 4.
  Sarcoma: These are cancers that originate from the cells in the muscular layer of the bladder.

Other Bladder Dysfunctions

Spina bifida is the most common congenital bladder dysfunction in the United States. This leads to permanent, disabling birth defects. Children with this disability are unable to ambulate without the assistance of wheel chairs and crutches. The bladder and bowel functions are also out of control in these children.

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