Question

Discuss the A&P of the urinary bladder and include one usual abnormal finding

Answer 1

The urinary bladder is a muscular sac that functions as the body’s urine storage tank, The bladder is pear shaped, becoming more oval as it fills with urine. Urine produced by the kidneys flows through the ureters to the urinary bladder, where is it stored before passing into the urethra and exiting the body.

Location : The urinary bladder is situated in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra.

Structure : The wall of the bladder is composed of 3 layers,

A) Outer layer of loose connective tissue, containing blood and lymphatic vessels and nerves.

B) Middle layer, consisting of a mass of interlacing smooth muscle fibres and elastic tissue ( detrusor muscle ).

C) Inner layer composed of transitional epithelium.

There are two urethral sphincters: the internal and external urinary sphincters. Part of the muscular bladder wall acts as the internal urethral sphincter and prevents urine from leaving the bladder to enter the urethra. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder.

Physiology : Bladder fills with urine, and the bladder walls stretch. Sensory nerves detect stretch and transmit this information to the spinal cord.Interneurons within the spinal cord relay the signal to the pelvic nerve. The pelvic nerve acts to contract the detrusor muscle, and stimulate the passage of urine. The sympathetic nervous system regulates the process of urine storage in the bladder. In contrast, the parasympathetic nervous system controls bladder contractions and the passage of urine

Function : Temporary storage of urine and Assists in the expulsion of urine

Difference : The length of the urethra is much shorter in women than in men,In males, it extends approximately 20 cm as it must traverse the length of penis, whereas it is only 4 cm in length in females.

Abnormal findings :Flacid bladder, when parasympathetic nerve is affected, The detrusor muscle will be paralysed, unable to contract. The spinal reflex does not function as a result the bladder will fill uncontrollably, becoming abnormally distended.   Urethritis which is inflammation of the urethra, sometimes caused by infection.