Urination, or deurination, is the process of excreting urine from the bladder. The process can be roughly divided into two phases. The first is gradual filling of the bladder with urine until the inner shell is stretched to the maximum limit. The second phase is the urge to deurinate. The urinary emptying reflex is provided by the innervation of the bladder. Urges are regulated by the autonomic system with electrically excitable cells in the dorsal brain.
Physiology of the hollow organ of the excretory system
The bladder is located in the pelvic cavity. The organ is a reservoir of smooth muscle and consists of two main parts.
- A body that expands and contracts depending on how much urine it contains.
- The neck, passing into the urinary organ, connecting the bladder with the external environment. The lower part of the cervix is called the posterior urethra.
Mucoid ureaconsists of stratified epithelium and connective tissue, penetrated by small blood vessels. On the basis of the mucosa there is a bladder triangle and an internal opening of the urethra. In the region of the opening there is a sphincter in the form of a circular muscle, which plays the role of a valve that prevents involuntary emission of urine.
The smooth muscle of the urea consists of three layers and is called the detrusor. The layers go to the neck of the organ and intertwine with the tissue, which contracts under the influence of excitation impulses. If the violation of the innervation of the bladder is caused by infravesical obstruction, then the detrusor is greatly enlarged.
The posterior urethra rests against the urogenital diaphragm and has a muscular layer called the external sphincter. The main part of the muscle consists of striated bundles, it also contains smooth fibers. The sphincter muscles are controlled by the nervous system.
Pauria (urination) reflex
As the urea fills up, there are rapid fluctuations in the form of a reaction of myocytes to the effect of an electrochemical pulse. Stimulates reflex contractions activation of nerve endings of stretching of the posterior urethra. Nerve impulses from receptors are carried to the sacral segments (roots) of the dorsal brain along the pelvic nerves.
The urination reflex is a set of periodically repeating processes.
- As the bladder fills with urine, the pressure increases.
- The contraction of the bubble results inaction sensitive stretch neurons.
- The flow of pulsation increases and intensifies the contractions of the bladder wall.
- Impulses from contractions are carried along the pelvic nerves to the roots of the spinal cord, and the central nervous system forms the urge to parure.
- The contraction of the bladder during urination relaxes the detrusor and the pressure stabilizes.
The paruria reflex will increase until the act of passing urine occurs.
Innervation of the bladder
The transmission of impulses is provided by the autonomic NS, dendrites and roots of the spinal cord. The main connection between the bladder and the central nervous system is provided by somatic nerves connected to each other and forming the sacral plexus. The pelvic nerves are composed of afferent (sensory) and efferent (motor) fibers. Signals about the degree of stretching of the urea are transmitted through afferent fibers. Impulses from the posterior urethra promote the activation of urination-oriented reflexes.
Emptying of the bladder can be reflex or voluntary. Unconditional urination is carried out due to neurons of sympathetic and parasympathetic innervation. Centripetal units of the nervous tissue are responsible for meaningful urination. When an organ is filled with urine, pressure rises, excited sensors send a signal to the dorsal brain, and then to the cerebral hemispheres.
What is parasympathetic innervation?
The activity of the organ of the excretory system is provided by reflex arcs, which are controlledspinal centers. Parasympathetic innervation of the bladder is carried out by efferent fibers. They are located in the sacral region of the dorsal brain. In the ganglia of the wall of the urea, preganglionic fibers originate. They innervate the detrusor. The connection of the external sphincter with the central nervous system is carried out through somatic motor fibers. Efferent fibers provoke detrusor contraction and relax the sphincter. With an increase in the tone of the parasympathetic center, urination occurs.
The role of sympathetic innervation
A distinctive feature of sympathetic innervation is the distancing from the organ, which is provided by the nerves. Retarding fibers that provide regulation are located in the sacral spinal cord. The sympathetic innervation of the bladder is carried out by the pelvic plexus. Sensory fibers have little effect on wall contractions. But on the other hand, they affect the formation of a feeling of overflow of the bladder, and sometimes pain. It is believed that the defeat of the afferent fibers does not lead to violations of the process of emptying the urethra.
Innervation of the bladder and neurology
In the anatomical structure, the detrusor muscle is located so that when it contracts, the volume of urine decreases. Urination is coordinated by two actions: contraction of the smooth muscles of the urea and relaxation of the sphincter tension. The processes run simultaneously. Neurogenic disorders are characterized by a loss of communication between these processes.
Disorders arise fromviolations of the innervation of the bladder in men and women of any age. The reasons can be different: injuries, vascular diseases, benign and malignant neoplasms. The stereotypical reaction of the body to empty and relax the sphincter is subject to cortical influences, which provides a meaningful act of removing urine from the body.
Neurogenic disorders of paruria
Any urination disorders are associated with abnormalities in the functioning of the nervous system and have a common term - neurogenic bladder. This concept means dysfunction of the hollow organ of the excretory system, due to congenital or acquired pathology of the NS.
There are three forms of bladder innervation disorders with urination disorders:
- Hyperreflexivity. Pathology is characterized by frequent urge to deurinate. The smooth muscles of the bladder contract in an intensive mode with a small volume of urine. Bladder hyperactivity is caused by a decrease in the number of M-cholinergic receptors. With a deficit of nervous regulation in smooth muscles, the formation of connections with neighboring cells develops. The bladder muscles are very active and immediately react to a small amount of urine. Detrusor contractions cause overactive bladder syndrome.
- Hyporereflex. Pathology is characterized by a decrease or lack of urge to empty. Sluggish and infrequent act of deurination. Even with a large amount of accumulated urine, the detrusor does not respond.
- Areflexivity. Urination occurs spontaneously as soon as the bladder is as full as possible.
Diseases causing disruption of innervation
Contribute to the disruption of innervation various pathologies of the brain and dorsal brain:
- A disease characterized by the presence of scattered throughout the NS without any localization of foci of connective tissue that replaces the organ (multiple sclerosis).
- Injury to the anterior columns of the dorsal brain and motor nerves. The muscles of the lower sphincter are in tension, there is a violation of the reflex contraction of smooth muscles.
- Spinal dysraphia. This form of violation of the innervation of the bladder and deurination disorder is characterized by spontaneous, uncontrollable human excretion of urine from the body.
- Spinal stenosis.
- Loss of small blood vessels in diabetes mellitus. Pathology extends to all processes of neurons.
- Injury to the bundle of roots of the lower lumbar, coccygeal, sacral spinal nerves.
Symptoms of deurination disorders
Symptoms vary depending on the degree of the disorder of the nervous system and the complexity of the disease. With cerebral lesions, strong and frequent urges occur, but the amount of urine is small. The patient complains of poor sleep due to nocturnal diuresis.
Characteristic signs of violation of the innervation of the bladder in the sacral region are:
- Incontinence or urine leakage.
- Atony of the bladder.
- No call.
Symptoms in the defeat of the supra-cross part are increased tension of the sphincter muscles and hypertension of the bladder. An inflammatory process may also occur due to overflow of the urea and difficulty emptying it.
Diagnosis and therapy
Recognition of urinary disorders and diagnosis is carried out by certain methods:
- Obtaining information by the doctor through questioning.
- Laboratory tests of urine and blood.
- Ultrasound of urinary organs and abdominal cavity.
- Recording of galvanic muscle activity (electroneuromyography).
- A test that measures the rate of urine flow during deurination (uroflowmetry).
- Method of examining the internal structure of the bladder.
- X-ray scan of the spine and skull.
- In some cases, an MRI may be ordered.
Treatment is prescribed by a urologist or neurologist. The therapy is complex and includes different methods:
- Drugs that improve blood supply and innervation of the bladder.
- Drugs that restore the normal functionality of the detrusor and sphincter.
- Pelvic Strengthening Exercises
- Physiotherapy treatments.
- Use psychotherapy if necessary.
If the above does not bring the desired result, a surgical operation is applied.
