What is urinary bladder? Structure, embryonic development, functions along diseases related to urinary bladder.

 URINARY BLADDER

Introduction

Urinary bladder is a hollow, muscular sac and pear-shaped distensible organ that lies on the pelvic floor. Bladder receives urine from the ureters, which are thick tubes running from each kidney down to the superior part of the bladder. Urine is collected in the body of the bladder and it is voided through the urethra. When bladder is full, it exhibits an oval shape and when empty, it is flattened by the overlying bowel and looks like the shape of the pear. The volume of human bladder vary from person to person. Range of the urine that can be held in the bladder is 400 ml to 1000 ml. A normal urinary bladder can hold about 400-600 ml of urine. The muscles of the bladder plays an important role in storage and emptying of urine. During micturition, the bladder wall contains specialized smooth muscles called detrusor muscles. The whole body of the bladder is divided into different sections are as following:

• apex
• body 
• neck
• fundus

apex lies superiorly, pointing towards the pubic symphysis. Body is the main part of the bladder and lies between the apex and the fundus. Fundus lies posteriorly and it is triangular in shaped. Neck is formed by the convergence of the fundus and two inferolateral surfaces. It is continuous with the urethra. There are two sphincters that are involved in the bladder are as following:

• internal urethral sphincter 
• external urethral sphincter

In male, it lies in front of rectum and separated by recto-vesical pouch and is supported by fibers of levator ani and of prostate gland. In female, it lies in front of the uterus, separated by vesico-uterine pouch and is supported by levator ani and in upper part of the vagina. The supply of oxygenated blood to the urinary bladder, it carries by the following arteries:

• superior vesical artery
• inferior vesical artery
• internal iliac arteries
• vaginal artery 
• uterine arteries

supply of deoxygenated blood to the urinary bladder, it carries be the following veins:

• vesical veins
• internal iliac veins
• vesical venous plexus

bladder receives both motor and sensory supply from sympathetic and parasympathetic nervous system. The nerves that are involved in the urinary bladder are as following:

• superior hypogastric plexus
• inferior hypogastric plexus
• pelvic splanchnic nerves
• pudendal nerve
• hypogastric nerve

the lymphatics that are involved in the urinary bladder are as following:

• external iliac lymph nodes
• internal iliac lymph nodes
• common iliac nodes

Embryonic Development Of Urinary Bladder

The bladder and urethra during the time of embryonic development are derived from the cloaca, a hindgut structure that is a common chamber for gastrointestinal and urinary waste. In 4th to 7th weeks of embryonic development, cloaca is divided into two parts by the uro-rectal septum and these two parts are as following:

• urogenital sinus 
• anal canal

urogenital sinus is further subdivided into three parts and these three parts are as following:

• upper part 
• pelvic part
• caudal part

the upper part of the urogenital sinus forms the bladder. The pelvic part forms prostate and membranous urethra in males and forms the entire urethra and some of the reproductive tract in females. The caudal part forms the spongy urethra and part of the female reproductive tract in males. The urinary bladder is drained by allantois. This only occurs during fetal development and becomes a fibrous cord and that is known as urachus. Remnant of the urachus can be found in adults. The bladder develops from the urogenital sinus, it absorbs the caudal parts of the mesonephric ducts, also known as wolffian ducts, become the trigone of the bladder. 

Functions Of Urinary Bladder

The main functions of urinary bladder are as following:

• stores urine
• allowing urination to be infrequent and controlled

Diseases Related To Urinary Bladder

Urinary disorders include any diseases or disorders that affect your kidneys, ureters, bladder and urethra or that can affect their function. Urinary disorder can cause serious and life threatening complications. Urinary disorder can be caused by cancer, infection, inflammation, injury, nervous system diseases, urine crystallization. Symptoms that are associated with urinary bladder disorders are as following:

• abdominal pain
• difficulty producing urine
• fever and chills
• frequent urination 
• blood in urine
• foul-smelling urine

common causes of urinary disorders include:

• dehydration
• kidney diseases
• kidney stones 
• urinary tract stones 
• trauma or injury 

some of the diseases of urinary bladder are as following:

• cystitis
• bladder cancer
• urinary stones
• hematuria
• urinary retention
• bed wetting
• dysuria
• cystocele

Cystitis

Cystitis often called painful bladder syndrome. It is a tricky condition. It is difficult to diagnose. Interstitial cystitis is a chronic bladder problem. In this problem, bladder holds pee after kidneys have filtered it. This condition causes pain and pressure below the belly button. Common symptoms of cystitis are as following:

• pain in lower tummy and lower back
• for women, pain in the vagina and vulva
• for men, pain in the scrotum, testicles and penis

to diagnose cystitis, following tests include:

• urinalysis
• cystoscopy
• prostate fluid culture
• postvoid residual urine volume

Dysuria

It is a condition in which patient feels discomfort, pain or burning during urination. It is more common in women than in men. More common causes of painful urination is infection. Infection can occur in kidneys, bladder, ureters and urethra. Urinary tract infection are mostly caused by bacteria that get into the urinary tract through the urethra. Factors that can cause this disorder are as following:

• diabetes 
• advanced age 
• pregnancy
• kidney stones 
• enlarged prostate gland

other symptoms of the urinary tract infection are as following:

• fever
• cloudy or bloody urine
• urge to urinate
• flank pain
• foul smelling urine

Hematuria

Hematuria is a condition in which blood is appeared in the urine. When the urine is pink or red this could be linked to blood in the urine and is called gross or visible hematuria. Various problems can cause this disorder are as following:

• kidney stones
• prostate infection 
• urinary infection
• kidney cancer
• bladder cancer
• kidney trauma

symptoms of this disease are as following:

• pink and red colored urine
• blood clots in urine

to diagnose this disease following tests include:

• urine tests
• imaging tests
• cystoscopy

Cystocele

Cystocele is also known as anterior vaginal prolapse. Cystocele occurs when the pelvic floor becomes weak or too much pressure is on the pelvic floor. This can happen during vaginal childbirth or with chronic constipation, violent coughing and heavy lifting. Common symptoms of this disease include:

• feeling pressure or fullness in vagina and pelvis
• bulge of tissue in vagina
• increased pelvic pressure

various problems can cause this disorder include:

• pregnancy and vaginal childbirth
• being overweight or obese
• chronic cough
• bronchitis 

to diagnose this disease following tests include:

• bladder and urine tests
• pelvic exam
• surgery