Define micturition, and describe the micturition reflex.

Question

Accepted Answer

Welcome back, everyone. Which of the following statements about the act of maturation is true. A the urinary bladder contracts followed by the contraction of the external sphincter. So that urine is flushed out. B the urinary bladder contracts followed by the relaxation of the external sphincter. So that urine is flushed out c the urinary bladder relaxes followed by the relaxation of the external sphincter. So that urine is flushed out or d the urinary bladder relaxes followed by the contraction of the external sphincter. So that urine is flushed out below, we have a partially filled in sketch of the urinary bladder as a whole. And we're going to begin by first defining what maturation states or is known as recall that maturation is also another term for urination. So let's outline the parts characterizing the urinary bladder structure, beginning with the y shaped tubules, which we will understand as being known as the ureters. The S are then met at a connecting point which we will label as the Trigon. And below that, we have the urethra tube which extends through the prostate gland and through the pelvic floor. So this is again the urethra and then we have the pelvic floor and then the square portion of our sketch. Sorry, the prostate gland is actually the circle portion here above the pelvic floor. So we have the square representing the pelvic floor and the circle representing the prostate gland in our sketch. Now, the red portion characterizing a muscle, which characterizes the circumference of the urinary bladder is known as the detrusor muscle. And at the most bottom portion of that muscle, we have this region in red, which I will label as the bladder, neck, sphincter muscle. So, bladder neck sphincter, we will also label the second red region that I have characterizing around the urethra and within the pelvic floor known as the external urethra sphincter muscle. So now with this urinary bladder sketch, labeled, let's outline the steps involved in urination. The first step we want to recall is going to be the contraction of the, the chooser muscle, which again, as we stated is a muscle that makes up the circumference of the urinary bladder. Once that muscle contracts, the second step of urination is going to be followed by the relaxation of the urinary sinter muscles. And this will allow then urine to pass from the urinary bladder through the urethra or sorry through the urethra sphincter muscles and to be flushed out from the bladder. So the third step would be again, urine expelled through the urethra where the final step of urination is where the bladder is now emptied and steps one and two will reverse, meaning that the truer muscle will now relax and the urinary sphincters will contract since there is no more urine to be expelled. Based on everything we've outlined, we would rule out choice a because it states that both the urinary bladder and external sphincter should both contract. And as we understood, it is the external sphincter that should actually relax in order for a urine to pass through the urethra. We will also rule out choice C because it states that both the urinary bladder and external sphincter should relax where it is only the external sphincter that should be relaxed where the urinary bladder should contract. And for choice D, we will also rule it out as an answer because it incorrectly states that the urinary bladder should relax and the external sphincter should contract. So B is actually going to be the only correct answer about the act of maturation or urination, which correctly states that the urinary bladder contracts followed by the relaxation of the external sphincter. So that urine can be flushed out. B is our final answer. I hope that this made sense and let us know if you have any questions.

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Define micturition, and describe the micturition reflex.

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