Urinary System Anatomy
Urinary system is of one of the vital system among human body parts. It consist of Kidneys, Ureters, Urinary Bladder and Urethra. The Urinary Tract is like the plumbing system, it drains Urine from the Kidney and plays an important role in maintaining the homeostasis, a set of complex processes to maintain the balance of water, ions, calcium and blood pressure in the human body.
The Kidneys are located along the wall of abdominal cavity. The left kidney is located higher than the right kidney. This is because the right side of the liver, located behind kidney, is larger compared to the left side. A layer of Adipose (fat tissues) surrounds the organ to protect it from any type of physical damage. Our Kidneys remove excessive water from the blood and filter out all impurities, metabolic waste, chemicals, and excessive ions in the form of Urine.
Ureters resemble a tube like structure that carry Urine from the Kidneys to the Urinary Bladder. It is 10-12 inch long and is present on the left as well as the right side of the body and parallel to the Vertebral Column. The flow of the Urine from the Kidney to the Bladder is due to gravity and Peristalsis (contraction and relaxation of muscles) of tissue muscles present in Ureter walls. Ureterovesical valves seal the point of entry of Ureter in to the Urinary Bladder to prevent Urine from flowing back.
Urinary Bladder is a sac like hollow organ that stores Urine. Located in body’s midline and at the inferior end of pelvis, Urinary Bladder holds the Urine that is brought in by Ureters. As the Urine pours in it, the hollow elastic walls stretches itself. The walls can stretch and hold around 600-800 milliliters of Urine.
Once the Urine is accumulated in the Urinary Bladder, urethra takes it out of the body. It is a tube like structure which passes from Urinary Bladder and extends till the exterior of the body. Urethra in females is about 2 inch long extending up to clitoris while in male is up to 8-10 inches long extending up to the tip of penis. Urethra is also a part of male reproductive system, carrying the sperms out of the body through penis. Urethral Sphincter Muscles controls the internal and external flow of Urine.
Urinary System Physiology
Kidney is majorly responsible for homeostasis by carrying several toxicity outside the body:
Ions – Kidneys extracts sodium, calcium, potassium, chloride, phosphate and magnesium and throws it out of the body in the form of Urine.
pH – Kidneys monitors the pH level in the body and regulate the hydrogen ion level along with bicarbonates to control the blood pH.
Osmolarity – Kidneys controls the amount of water filtered outside the body and maintains the osmotic balance in the body.
Blood Pressure – Kidneys continuously monitors the blood pressure to maintain the Homeostasis.
Kidneys remove excessive waste from the blood through filtration process. Our blood consists of unwanted substances coming from things we eat and drink. Kidney automatically removes excessive salts and minerals to leave just the quantity the body needs. Every day about 180 liters of blood passes through the Kidneys via the renal arteries. Millions of tiny filters, called glomeruli, inside the Kidneys separate wastes and water from the blood.
Storage and Excretion of Wastes
When the Urine passes from Ureters to Urinary Bladder, it starts filling up the bladder and when it reaches the maximum level, the brain and the spinal cord get the signal. These signals cause relaxation of the internal Urethral Sphincter and cause the sensation of needing to Urinate. Urination can be delayed as long as the Urinary Bladder does not exceed its maximum filling volume, but as the volume increases nerve signals gets stronger leading to greater discomfort and desire to urinate.
Production of Hormones
Kidneys deal with several Hormones during the entire process namely:
- Calcitriol – Calcitriol is an active form of vitamin D in the human body produced by the Kidneys from the UV radiation striking the skin.
- Erythropoietin – It is a hormone produced by the Kidneys to stimulate the production of red blood cells
- Renin – Renin is not a hormone itself, but an enzyme that the Kidneys produces to increase the blood volume and maintain the pressure
In our next blogs, we will explain you about urinary infection symptoms, Urinary Tract Infection (UTI), etc. which is one of the most common disease in India and other developing countries.
For more details about our Urinary system and the disease, please visit our website: www.mpuh.org/centreforroboticsurgery