While the nurse is giving morning care to a patient who sustained a fractured pelvis and bilateral fractures of the femur in a motorcycle accident yesterday, the patient complains of shortness of breath and is audibly wheezing. An assessment of the oxygen saturation reveals 76%. The initial intervention by the nurse should be to:

Correct Answer: C

Rationale: Sudden shortness of breath, wheezing, and 76% oxygen saturation post-fracture suggest a fat embolism, a life-threatening complication from long bone trauma. Administering oxygen at 4-5 L/min via nasal cannula is the initial step to boost oxygenation, stabilizing the patient while further help is sought. Alerting the code team is premature without first aiding breathing. Informing the charge nurse follows oxygen delivery, as does raising to high Fowler's to ease breathing but oxygen comes first. This rapid response addresses hypoxia directly, critical in trauma where respiratory decline can escalate fast, buying time for diagnosis and treatment.

Correct Answer: D

Rationale: Fixators stabilize the origin of the agonist (prime mover), ensuring its force is directed efficiently toward the intended movement. For example, during arm abduction, scapular fixators (e.g., trapezius) hold the scapula steady so the deltoid can lift the arm. Synergists assist the agonist by refining motion, not stabilizing origins. The agonist is the main mover, not a stabilizer. Antagonists oppose the agonist. Fixators' role in anchoring the origin enhances movement precision, making it the correct answer, as it supports the agonist's action by preventing unwanted shifts at the stationary attachment, a key aspect of coordinated muscle function.

Correct Answer: D

Rationale: The external anal sphincter, a voluntary skeletal muscle, keeps the anal canal and anus closed to prevent defecation until appropriate, allowing Tim to wait. Bulbospongiosus aids in urination and erection, not anal control. Ischiocavernosus supports erection, not defecation. Obturator internus rotates the thigh, unrelated here. The external anal sphincter is the correct answer, as it provides conscious control over defecation, distinct from the involuntary internal sphincter, and is key in maintaining continence under digestive distress.

Correct Answer: B

Rationale: Hip extension, critical for climbing steps, is primarily powered by the gluteus maximus, which extends the thigh backward. Weakness here impairs stair ascent, while intact hip flexion (iliopsoas) and knee flexion/extension (hamstrings/quadriceps) suggest a specific issue. Adductor magnus adducts, not extends. Gluteus medius abducts and stabilizes. Semitendinosus flexes the knee, not hip extension. Gluteus maximus is the correct answer, as its damage aligns with isolated hip extension weakness, a key mover in upward locomotion.

Correct Answer: C

Rationale: The body has three muscle types: cardiac, smooth, and skeletal, each with distinct roles. Cardiac muscle, in the heart, pumps blood involuntarily. Smooth muscle, in organs like the intestines, manages involuntary tasks like digestion. Skeletal muscle, attached to bones, drives voluntary movements like walking. Suggesting four or five types might confuse these with subtypes (e.g., fast-twitch skeletal) or non-muscle tissues, but anatomy recognizes only three based on structure and control. Two undercounts by omitting one, missing the full scope. Three aligns with histological and functional classification, reflecting their specialized purposes cardiac for circulation, smooth for visceral action, skeletal for locomotion. This trio covers all muscular functions, providing a clear, consistent framework for understanding the body's movement and maintenance systems.