Which part of brain sends voluntary motor signals to smooth muscles of urinary bladder when the bladder is
filled with urine?
(1) Medulla
(2) Cerebral cortex
(3) Hypothalamus
(4) Brain stem
Answers
Answer:
The neural control of micturition
Clare J. Fowler, Derek Griffiths, and William C. de Groat
Additional article information
Abstract
Micturition, or urination, occurs involuntarily in infants and young children until the age of 3 to 5 years, after which it is regulated voluntarily. The neural circuitry that controls this process is complex and highly distributed: it involves pathways at many levels of the brain, the spinal cord and the peripheral nervous system and is mediated by multiple neurotransmitters. Diseases or injuries of the nervous system in adults can cause the re-emergence of involuntary or reflex micturition, leading to urinary incontinence. This is a major health problem, especially in those with neurological impairment. Here we review the neural control of micturition and how disruption of this control leads to abnormal storage and release of urine.
The storage and periodic elimination of urine depend on the coordinated activity of smooth and striated muscles in the two functional units of the lower urinary tract, namely a reservoir (the urinary bladder) and an outlet consisting of the bladder neck, the urethra and the urethral sphincter1,2. The coordination between these organs is mediated by a complex neural control system that is located in the brain, the spinal cord and the peripheral ganglia.
The lower urinary tract differs from other visceral structures in several ways. First, its dependence on CNS control distinguishes it from structures that maintain a level of function even after the extrinsic neural input has been eliminated. It is also unusual in its pattern of activity and in the organization of its neural control mechanisms. For example, the bladder has only two modes of operation: storage and elimination. Thus, many of the neural circuits that are involved in bladder control have switch-like or phasic patterns of activity, unlike the tonic patterns that are characteristic of the autonomic pathways that regulate cardiovascular organs. In addition, micturition is under voluntary control and depends on learned behaviour that develops during maturation of the nervous system, whereas many other visceral functions are regulated involuntarily.
Owing to the complexity of the neural mechanisms that regulate bladder control, the process is sensitive to various injuries and diseases. This Review summarizes the results of recent studies in animals and humans that have provided new insights into the sensory and motor mechanisms that underlie voluntary and reflex micturition, the changes in neural pathways that occur following disease or injury that alters lower-urinary-tract function, and new therapies for the treatment of neurogenic bladder dysfunction.
Peripheral innervation of the urinary tract
The requirement for voluntary control over the lower urinary tract necessitates complex interactions between autonomic (mediated by sympathetic and parasympathetic nerves) and somatic (mediated by pudendal nerves) efferent pathways1,2 (FIG. 1a). The sympathetic innervation arises in the thoracolumbar outflow of the spinal cord, whereas the parasympathetic and somatic innervation originates in the sacral segments of the spinal cord. Afferent axons from the lower urinary tract also travel in these nerves.
please mark me as brainleast
Answer:
B
Explanation:
cerebral cortex sends voluntary motor signals to smooth muscles of urinary bladder when the bladder get filled with urine