Urinary System Clinical Significance

The urinary system refers to the structures that produce and transport urine to the point of excretion. In the human urinary system, there are two kidneys that are located between the dorsal body wall and parietal peritoneum on both the left and right sides.

The formation of urine begins within the functional unit of the kidney, the nephrons. Urine then flows through the nephrons, through a system of converging tubules called collecting ducts. These collecting ducts then join together to form the minor calyces, followed by the major calyces that ultimately join the renal pelvis. From here, urine continues its flow from the renal pelvis into the ureter, transporting urine into the urinary bladder.

Male and Female Urinary system (????? ?? ????? ????? ???????)

The anatomy of the human urinary system differs between males and females at the level of the urinary bladder. In males, the urethra begins at the internal urethral orifice in the trigone of the bladder, continues through the external urethral orifice, and then becomes the prostatic, membranous, bulbar, and penile urethra. Urine exits through the external urethral meatus. The female urethra is much shorter, beginning at the bladder neck and terminating in the vaginal vestibule.

Urinary system Anatomy (????? ??????? ?? ??????? ????)

Under microscopy, the urinary system is covered in a unique lining called urothelium, a type of transitional epithelium. Unlike the epithelial lining of most organs, the transitional epithelium can flatten and distend. Urothelium covers most of the urinary system, including the renal pelvis, ureters, and bladder.

Urinary system Function (????? ??????? ?? ?????)

The main functions of the urinary system and its components are to:

• Blood volume and composition regulation e.g. sodium, potassium, and calcium
• Regulation of blood pressure
• pH homeostasis of the blood regulation
• Contributes to the production of red blood cells by the kidney
• Help synthesize calcitriol, which is an active form of Vitamin D
• Stores waste product, mainly urea and uric acid

Urine formation (????? ?? ????)

Average urine production in adult humans is about 1–2 liters per day, depending on the state of hydration, activity level, environmental factors, weight, and the individual’s health. Producing too much or too little urine requires medical attention. Polyuria is a condition of excessive urine production (> 2.5 L/day). Oliguria when < 400 mL (milliliters) is produced, and anuria one of < 100 mL per day.

The first step in urine formation is the filtration of blood in the kidneys. In a healthy human, the kidney receives between 12 and 30% of cardiac output, but it averages about 20% or about 1.25 L/min.

The basic structural and functional unit of the kidney is the nephron. Its chief function is to regulate the concentration of water and soluble substances like sodium by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

In the first part of the nephron, Bowman’s capsule filters blood from the circulatory system into the tubules. Hydrostatic and osmotic pressure gradients facilitate filtration across a semipermeable membrane. The filtrate includes water, small molecules, and ions that easily pass through the filtration membrane. The amount of filtrate produced every minute amounts to 180 liters per day. 

The urinary system is regulated by the endocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone.

Regulation of concentration and volume (???????? ?? ?????? ?? ???????)

The urinary system is under the influence of the circulatory system, nervous system, and endocrine system.

Aldosterone plays a central role in regulating blood pressure through its effects on the kidney. It acts on the distal tubules and collecting ducts of the nephron and increases the reabsorption of sodium from the glomerular filtrate. Reabsorption of sodium results in retention of water, which increases blood pressure and blood volume.

Antidiuretic hormone (ADH), is a neurohypophysial hormone found in most mammals. Its two primary functions are to retain water in the body and vasoconstriction. Vasopressin regulates the body’s retention of water by increasing water reabsorption in the collecting ducts of the kidney nephron. Vasopressin increases water permeability of the kidney’s collecting duct and distal convoluted tubule by inducing translocation of aquaporin-CD water channels in the kidney nephron collecting duct plasma membrane.

Urination (????? ????? ????)

It is the ejection of urine from the urinary bladder through the urethra to the outside of the body. In healthy humans (and many other animals), the process of urination is under voluntary control. In infants, some elderly individuals, and those with neurological injury, urination may occur as an involuntary reflex.

Physiologically, micturition involves coordination between the central, autonomic, and somatic nervous systems. Brain centers that regulate urination include the pontine micturition center, periaqueductal gray, and the cerebral cortex. In placental mammals, the male ejects urine through the penis, and the female through the vulva.

Urinary system Diseases (????? ??????? ?? ???)

The diseases related to the urinary system include:

• Benign prostatic hyperplasia
• Interstitial cystitis
• Kidney stone
• Prostatitis
• Proteinuria
• Renal failure
• Urinary tract infection
• Incontinence
• Retention

Urinary system Clinical significance (????? ??????? ??????? ?????)

The urologic disease can involve congenital or acquired dysfunction of the urinary system. As an example, urinary tract obstruction is a urologic disease that can cause urinary retention.

Diseases of the kidney tissue are normally treated by nephrologists, while diseases of the urinary tract are treated by urologists. Gynecologists may also treat female urinary incontinence.

Diseases of other bodily systems also have a direct effect on urogenital function. For instance, it has been shown that protein released by the kidneys in diabetes mellitus sensitizes the kidney to the damaging effects of hypertension.

Diabetes also can have a direct effect on urination due to peripheral neuropathies, which occur in some individuals with poorly controlled blood sugar levels.

Urinary incontinence can result from a weakening of the pelvic floor muscles caused by factors such as pregnancy, childbirth, aging, and being obese or overweight. Pelvic floor exercises known as Kegel exercises can help in this condition by strengthening the pelvic floor. There can also be underlying medical reasons for urinary incontinence which are often treatable. In children, the condition is called enuresis.

Some cancers also target the urinary system, including bladder cancer, kidney cancer, ureteral cancer, and urethral cancer.