ATI RN
Muscular System Exam Questions Questions
Question 1 of 5
Which of the following helps an agonist work?
Correct Answer: A
Rationale: A synergist assists an agonist, the prime mover, by enhancing its action or stabilizing joints, like brachioradialis aiding biceps in elbow flexion. A fixator stabilizes the origin bone, indirectly supporting but not directly helping the agonist's motion. An insertion is the muscle's moving attachment, not a helper muscle. An antagonist opposes the agonist (e.g., triceps vs. biceps), hindering, not aiding. Synergists' cooperative role boosts efficiency and precision, distinguishing them from stabilizing, structural, or opposing functions, essential for coordinated movement.
Question 2 of 5
The large muscle group that attaches the leg to the pelvic girdle and produces extension of the hip joint is the group.
Correct Answer: A
Rationale: Gluteal muscles (gluteus maximus, medius, minimus) attach the leg to the pelvic girdle, with maximus extending the hip (e.g., standing up). Obturators rotate the thigh. Adductors pull it inward. Abductors (e.g., gluteus medius) move it outward, not extending. Gluteals' size and extension role distinguish them, key for hip motion.
Question 3 of 5
What causes direct damage to the cells?
Correct Answer: A
Rationale: Toxins vary in their cellular targets and effects. Cytotoxins directly harm cells by disrupting membranes, inhibiting protein synthesis, or inducing apoptosis, leading to tissue damage or organ dysfunction, as seen with diphtheria toxin. Neurotoxins target nerve cells, impairing signaling, like botulinum toxin. Enterotoxins affect intestinal cells, causing symptoms like diarrhea, as with cholera toxin. Leukocidins destroy white blood cells, aiding bacterial evasion. Cytotoxins' broad cellular toxicity, applicable across cell types, contrasts with the specialized actions of others, making them the primary agents of direct cell damage in this context.
Question 4 of 5
In humans, if the diaphragm is pushed upward, there is a decrease in chest volume. The decrease is followed by:
Correct Answer: B
Rationale: The diaphragm's upward movement, as in exhalation, reduces chest volume. Per Boyle's law, this increases pressure in the lungs, forcing air out as the higher internal pressure exceeds atmospheric pressure. Inhalation occurs when the diaphragm descends, expanding volume and lowering pressure, drawing air in. The upward push compresses the chest, driving exhalation, a fundamental respiratory mechanism ensuring gas exchange, distinct from inhalation's volume increase and pressure drop.
Question 5 of 5
The tiny projections in the small intestine adapted for absorption are called:
Correct Answer: B
Rationale: The small intestine maximizes nutrient absorption via villi finger-like projections lining its walls. Covered in microvilli, they vastly increase surface area, allowing efficient uptake of sugars, amino acids, and fats into the bloodstream. Venules are blood vessels, alveoli handle lung gas exchange, and nephrons filter kidney blood. Villi's specialized structure and location enhance digestion, distinguishing them as the key absorptive feature, critical for nutrient distribution in the body.