When the dartos muscle contracts, it causes which of the following?
decreases surface area of the scrotum, increases its thickness, and prevents heat loss
allows scrotum and testes to hang lower from the body
elevates the scrotum
increases surface area of the scrotum, decreases its thickness, and allows heat loss
The Correct Answer is A
A. decreases surface area of the scrotum, increases its thickness, and prevents heat loss: The dartos is a layer of smooth muscle within the superficial fascia of the scrotum. When it contracts in response to cold temperatures, it causes the scrotal skin to wrinkle and tighten. This reduction in surface area and the resulting thickening of the wall minimizes radiant heat loss to the environment.
B. allows scrotum and testes to hang lower from the body: This occurs when the dartos and cremaster muscles relax, typically in response to warm temperatures. Moving the testes away from the pelvic cavity promotes cooling by increasing the distance from core body heat. Relaxation is a heat-dissipating mechanism rather than a result of muscle contraction.
C. elevates the scrotum: While the dartos contributes to the tightening of the sac, the primary muscle responsible for the vertical elevation of the testes toward the inguinal canal is the skeletal cremaster muscle. The dartos primarily affects the texture and surface area of the skin itself. Elevation is a coordinated effort but is specifically the cremasteric reflex.
D. increases surface area of the scrotum, decreases its thickness, and allows heat loss: This description characterizes the physiological state of the scrotum during heat exposure. When the dartos muscle is flaccid, the skin becomes thin and smooth, maximizing the area available for cooling. This is the opposite effect of the contraction described in the question stem.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
A. is not reabsorbed by the tubule cells: While some substances like mannitol act as osmotic diuretics because they remain in the tubule lumen, alcohol follows a different physiological pathway. Alcohol is a lipid-soluble molecule that can diffuse across membranes rather than relying on tubular transport inhibition. Its diuretic effect is neuroendocrine in origin rather than purely osmotic.
B. increases the rate of glomerular filtration: Although alcohol can cause minor changes in systemic blood pressure, it does not significantly increase the glomerular filtration rate as its primary mode of action. A slight increase in flow would not account for the profound volume of dilute urine produced. The primary diuretic effect occurs later in the distal segments of the nephron.
C. increases secretion of ADH: Increased secretion of antidiuretic hormone would result in the insertion of aquaporins and the retention of water, leading to concentrated urine. This is the opposite of the clinical effect observed with alcohol consumption. Stimulating ADH would prevent diuresis rather than promote it, leading to fluid volume expansion.
D. inhibits the release of ADH: Ethanol directly suppresses the hypothalamic-hypophyseal tract, reducing the secretion of antidiuretic hormone from the posterior pituitary. Without ADH, the collecting ducts remain impermeable to water, preventing reabsorption and resulting in the excretion of large volumes of dilute urine. This inhibition is the primary cause of alcohol-induced dehydration.
Correct Answer is D
Explanation
A. not develop secondary sex characteristics: Secondary sex characteristics, such as muscle growth and hair distribution, are driven by testosterone produced by interstitial cells. Since LH levels are normal, these cells will still be stimulated to produce adequate testosterone. The boy would likely appear physically mature in terms of external male characteristics.
B. have impaired function of interstitial cells: Interstitial endocrine cells are specifically regulated by luteinizing hormone, which the question states is functioning normally. These cells will continue to synthesize testosterone regardless of the FSH deficiency. Their endocrine function remains intact because their primary tropic hormone is still present in the circulation.
C. be impotent (unable to have an erection): Erection is a neurovascular reflex mediated by the parasympathetic nervous system and is not directly dependent on FSH. While low testosterone can decrease libido, LH is present to maintain testosterone levels. Therefore, the physiological mechanism for erection should remain functional in this mature male.
D. be unable to produce viable sperm: Follicle-stimulating hormone is strictly required to stimulate the sustentacular cells to facilitate the final stages of sperm maturation. Without FSH, the process of spermatogenesis cannot be completed effectively, leading to infertility. The individual would produce few or no functional spermatozoa despite normal hormonal levels.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.