Female Urinary System consists of following organs :
- Kidneys : Every normal Female has a pair of kidneys in her abdomen attached to the posterior abdominal wall. Each kidney is a bean shaped, urine forming Organ. Kidney has an outer covering of Capsule. Inner Matrix is further divided into Renal Cortex (outer half) and Medulla (inner half). Urine formed in kidney collects inside small projections into the Medulla known as Calyces. Calyces pour Urine into the widened most medial part of the Kidney; the Renal Pelvis. Kidneys are connected to the Ureters via Renal Pelvis medially. Kidneys receive their blood supply via Renal Vessels from Abdominal Aorta. Structural and Functional unit of the Kidney is Nephron. A nephron starts as Glomerulus which consists of a bunch of vessels inside a capsule. Glomerulus is covered from outside by the Bowman's Capsule. Glomerulus leads to the Proximal Convoluted Tubule which is a convoluted tube like structure. It ascends down as Loop of Henle. This Loop leads to Distal Convoluted Tubule which ends in Collecting Ducts. All these parts are richly supplied with blood vessels.
- Ureters : After passing from kidney Urine collects inside the Renal Pelvis medially. Renal Pelvis leads to these long connecting ducts known as Ureters. They lead from Renal Pelvis to the Urinary Bladder. Important Iliac Vessels and Nerves cross it along its way downwards. They are made up of Smooth Muscle Fibres inside their walls. These Smooth Muscles contract rhythmically and propel Urine forwards towards the Urinary Bladder.
- Urinary Bladder : Urinary Bladder is a pouch like structure which stores Urine. Its shaped like a three sided pyramid with tilted and placed down on one of its sides. Its made up of flexible Transitional Epithelium which changes shape and expands as Urine fills up. It is present inside the Pelvis in middle but extends to Anterior Abdominal Wall as it fills. It has got an opening on its inferior part to Urethra which is guarded by Sphincters. It has got a muscle in its wall which is called Detrusor Muscle. It is supplied by Autonomic Nervous System.
- Urethra : Urine collected inside Urinary Bladder exits through Urethra. In Females Urethra is not included in Genital System as Vagina has a separate opening. However Urethra opens in the vestibule of the Vulva adjacent to Vagina on its Anterior wall. It is guarded by two Sphincters. Internal Sphincter is involuntary and External Sphincter is voluntary and can be controlled by will. It is usually 4-5 cm long.
FUNCTIONAL MECHANISM :
- Urine Formation : Urine is formed inside Kidneys by filtration of the Blood. It is done in a step wise manner. First Pressure Filtration takes place at Glomerulus, waste products along with glucose and essential molecules and ion are excreted out of the Blood. Later the important substances are taken back into the Blood and water is reabsorbed making Urine concentrated. It is concentrated more in Collecting Ducts.
- Urine Movement : Urine formation is complete at the end of the Collecting Ducts and consists of water and waste products like Urea, Uric acid and other ions etc. It is then pushed into the Calyces via the rhythmic contraction of the Smooth Muscles in their walls. This Rhythmic Movement is called Peristalsis. It continues downwards till Urinary Bladder and travels in forms of small waves. Urine is pushed from Calyces into Renal Pelvis, and through them to Ureters and ultimately Urinary Bladder.
- Urination (Micturition) : It refers to the excretion of the Urine and voiding of the Bladder. It starts as contractions of Detrusor Muscle of the Urinary Bladder at intervals under the action of the Parasympathetic System. Later when Micturition is required Sphincters in the proximal portion of Urethra and ending of the Bladder are relaxed and Urine travels down the Urethra to outside the Body.
- Kidneys also produce Erythropoietin in response to low oxygen levels. It is an important regulator of the Haemoglobin formation. Erythropoietin induces production of Haemoglobin and Red Blood Cells.
FUNCTIONAL SIGNIFICANCE :
- By excretion of Urine, Female Urinary System is involved in waste product removal from the Body.
- Urinary System is involved in mineral ion balance (calcium, sodium, potassium etc.) which is vital for the Body.
- It also regulates pH of the Blood by regulating bicarbonate release.
- Urinary System of Females also controls Blood Volume and Blood Pressure by the formation of Urine.
- Urinary System helps maintaining Blood Haemoglobin levels by the production of Erythropoietin.
CLINICAL SIGNIFICANCE :
- Female Urinary System is often involved in infectious diseases like infection of Urethra by Bacteria or Fungi.
- Urinary System of Females can develop cancer in its various parts like Urinary Bladder, Kidney, Ureter etc.
- Urinary System of Females can be defective by Birth or become defective later. It is classified under Urologic Disease.