The bladder is a hollow, muscular, cystic organ in the body that stores and excretes urine. The bladder is very flexible and its location, shape, size, and thickness of the bladder wall will vary with the degree of filling of urine.
1, the adjoining relationship of the bladder The adjoining relationship of the bladder is extremely complex. In men, the upper part of the bladder is the intestinal tube in the abdominal cavity, separated by the peritoneum, the posterior part of the bottom of the bladder is the rectum, and its outer bottom is the seminal vesicle and ureter. In females, the posterior aspect of the bladder base is followed by the uterus and anterior vaginal wall in front of the rectum.
The neck of the bladder is connected to the urethra. In men, there is also prostatic tissue at the neck of the bladder. Therefore, transurethral examination and treatment of the bladder is the main modality of urology. Common minimally invasive transurethral bladder operations as well as procedures include cystoscopy, transurethral bladder tumor resection, and transurethral bladder lithotripsy for lithotripsy. Additional minimally invasive urological procedures can be achieved through this natural cavity.
The bladder has a rich blood supply and is surrounded by a complex vascular system. It is particularly important for the urologist to understand the fine anatomy adjacent to the bladder to accurately identify the individual anatomical landmarks during bladder surgery.
2, the structure of the bladder wall The bladder wall can be divided into three structural layers, namely the bladder mucosa, the forced urinary muscle layer and the epithelium.
The mucosa of the bladder consists of the uroepithelium. The epithelium of the urinary tract forms a water-proof layer through intercellular junctions, which insulates the submucosal structures from the chemicals in the urine. When the bladder mucosa becomes diseased (e.g., in inflammatory bladder disease), the urinary epithelium cells are shed and this barrier is broken, and urinary chemicals erode the submucosal structures, producing urinary irritation, which can be detected by urinalysis with epithelial cells. The bladder mucosa is rich in microvessels, and in the presence of bladder disease, hematuria can occur when the mucosal vessels rupture. Therefore, hematuria is a common manifestation of bladder disease.
The submucosa of the bladder contains connective tissue, the lamina propria, which is rich in microvascular structures. In the case of bladder cancer, it is especially important to clarify whether cancer cells have infiltrated into the lamina propria to determine the stage of bladder cancer.
The muscular layer of the bladder is thicker and consists of multiple layers of interwoven muscle fibers. The muscular layer of bladder can be divided into superficial and deep muscular layers. In bladder cancer patients, it is important to clarify the presence or absence of muscle layer infiltration of cancer cells and the depth of muscle layer infiltration to determine the prognosis of bladder cancer and to choose the treatment plan. Enhanced CT examination can help doctors understand whether bladder cancer has muscle layer infiltration or not.
3. Innervation of bladder The bladder is richly innervated by efferent nerves, which play the role of contraction and diastole of bladder muscle layer. The bladder wall is rich in afferent sensory nerve fibers, which can cause pain in the lower abdomen when there is overfilling of the bladder, bladder stones, inflammation, malignant tumors and other diseases, and can also lead to increased sensory afferents to the bladder, resulting in frequent urinary urgency as well as urge incontinence.
4, the function of the bladder Under normal circumstances, the ureter drains the urine produced by the kidneys into the bladder. A normal bladder has good elasticity to ensure that it has a low internal pressure when storing urine. The normal adult bladder has a capacity of about 350-500 ml. When the bladder is full, the pressure in the bladder rises, which stimulates the detrusor receptors in the bladder wall and transmits the sensation to the voiding center, which can produce the urge to urinate. When environmental conditions allow, the bladder detrusor muscle contracts and the internal and external urethral sphincter relaxes and then urinates. When environmental conditions do not allow urination, the higher centers of the brain, can consciously inhibit this urge to urinate, which is called holding urine. In acute urinary retention, painful sensation occurs when the bladder is overfilled, and the contraction of the bladder forcing muscles decreases at this time.
When empty, the bladder is conical, below the pubic symphysis and located in the pelvis. When full, the bladder is ovoid and can be higher than the pubic symphysis. Generally, the doctor can understand the filling state of the bladder by simple palpation and percussion to make a preliminary determination of the size and shape of the bladder. When the bladder is full, the presence of bladder diverticula, stones, and tumors can be determined by ultrasound, CT, and MRI imaging to understand the smoothness of the bladder wall. During urination, the rate of urine flow can be measured to understand the rapidity of urination and to clarify whether there is obstruction to urination. After voiding, you can measure the residual urine in the bladder by ultrasonography and thus understand the severity of voiding difficulties. Urodynamic examination can also be used to understand the relationship between changes in bladder volume and bladder pressure, and to understand the compliance (elasticity) of the bladder; during voiding, the ability of the bladder forcing muscle to coordinate with the urethral sphincter can be clarified by recording changes in pressure in the urethra. After urination, urine can be collected for routine urine examination to understand whether there is urinary tract infection; urine exfoliative cytology examination can be performed to understand whether there are shed cancer cells.
5.Bladder diseases Bladder-related diseases are commonly seen in: bladder cancer, cystitis, bladder stones, urinary incontinence, overactive bladder, hematuria, dyspareunia, urinary retention, etc. These disorders, often suggest abnormalities in the structure or function of the bladder. When patients develop urinary symptoms (such as hematuria, urinary frequency, urinary urgency, urinary pain, and difficulty in urination), they need to be seen by a urologist in a timely manner to improve the examination under the guidance of a urologist and to clarify whether they have bladder disease in order to avoid delaying or aggravating further damage to bladder structure and function from these diseases.