What are the steps of micturition reflex?
Normal urination (micturition) occurs in the following stages:
- Urine is made in the kidneys.
- Urine is stored in the bladder.
- The sphincter muscles relax.
- The bladder muscle (detrusor) contracts.
- The bladder is emptied through the urethra and urine is removed from the body.
What is a micturition reflex?
The micturition reflex is a bladder-to-bladder contraction reflex for which the reflex center is located in the rostral pontine tegmentum (pontine micturition center: PMC). There are two afferent pathways from the bladder to the brain. One is the dorsal system and the other is the spinothalamic tract.
How is micturition controlled?
Micturition is thus under cortical control as well as mediated by the spinal reflex arc, which inhibits the pontine center until it is deemed appropriate to void. In addition, the motor cortex controls the voluntary muscle of the external urethral sphincter.
What are the 3 phases of normal micturition?
This diagram in this article illustrates the three phases: phase 1: filling and storage; phase 2: voiding and phase 3: termination of voiding. The normal bladder fills and empties in cycles.
What initiates the micturition reflex quizlet?
What initiates the micturition reflex? Stretch receptors in the wall of the urinary bladder signal the sacral region of the spinal cord.
What is the micturition reflex quizlet?
Definition of micturition. The process of filling the bladder until it reaches a threshold level at which the autonomic micturition reflex results in emptying of the bladder, or if it fails, the conscious desire to urinate. Smooth muscle that lines the bladder.
What is micturition reflex Class 11?
Micturition is the process by which the urine from the urinary bladder is excreted. As the urine accumulates, the muscular walls of the bladder expand. The walls stimulate the sensory nerves in the bladder, setting up a reflex action. This reflex stimulates the urge to pass out urine.
What divisions of the nervous system is involved with micturition?
Central control of micturition is performed by 3 areas: the sacral micturition center, the pontine micturition center, and the cerebral cortex. The sacral micturition center is located at the S2-S4 levels and is responsible for bladder contraction.
What is the storage reflex?
In the storage phase, impulses travel to the EUS via the pudendal nerve (nerve roots S2-S4) to nicotinic (cholinergic) receptors on the striated muscle, resulting in contraction of the EUS. This prevents any urine from leaking out.
Where is the micturition reflex initiated *?
Micturition is initiated by a supraspinal reflex pathway that passes through a centre in the brainstem. The pathway is triggered by myelinated afferents (Aδ-fibres), which are connected to the tension receptors in the bladder wall.
Where is the micturition reflex initiated * 1 point?
The micturition reflex is ultimately generated from the level of the spinal cord after it receives reflexes from the pontine region in the brain. Once the bladder and the urethra receive the signals to empty the bladder, the two sphincters relax and the detrusor muscle causes the contractions of the bladder.