Correct Answer: D

Rationale: The correct answer is D: It helps equalize air pressure on both sides of the tympanic membrane. The eustachian tube connects the middle ear to the nasopharynx, allowing for pressure equalization. During activities like swallowing or yawning, the tube opens to allow air to flow in or out, maintaining equal pressure. This function is crucial for proper hearing and preventing discomfort or damage to the tympanic membrane. Choice A is incorrect as cerumen is produced by ceruminous glands in the ear canal, not the eustachian tube. Choice B is incorrect as the eustachian tube normally remains closed and opens only intermittently during specific actions. Choice C is incorrect as the eustachian tube does not connect the middle and outer ear; it connects the middle ear to the nasopharynx.

Correct Answer: C

Rationale: The correct answer is C: Bell's palsy. Bell's palsy is characterized by sudden weakness or paralysis of the facial muscles, resulting in drooping of the face, inability to raise the eyebrow or close the eye, and difficulty with facial expressions and functions like whistling. In this case, the patient's symptoms of left-sided facial paralysis point towards Bell's palsy as the likely diagnosis. Cushing's syndrome (A) is a hormonal disorder, Parkinson's syndrome (B) is a neurodegenerative disorder affecting movement, and a cerebrovascular accident (D) typically presents with more generalized neurological deficits rather than isolated facial paralysis.

Correct Answer: D

Rationale: The correct answer is D because a normal pupillary light reflex involves the constriction of both pupils in response to bright light. This reflex is controlled by the autonomic nervous system, specifically the parasympathetic nervous system. When light is detected by the retina, signals are sent to the brain which then triggers the constriction of both pupils to reduce the amount of light entering the eye. Choices A, B, and C are incorrect because they do not accurately describe the pupillary light reflex. Vision convergence, light reflection, and focusing the image at the center of the pupil are not directly related to the pupillary light reflex.

Correct Answer: C

Rationale: The correct answer is C: Tilt the child's head slightly toward the examiner. This position straightens the ear canal, facilitating visualization. Pulling the pinna down (A) can cause discomfort and obstruct the view. Pulling the pinna up and back (B) is incorrect for a child under 3 years old as it straightens the ear canal in adults. Having the child touch his chin to his chest (D) is unnecessary and may lead to improper examination positioning.

Correct Answer: A

Rationale: The correct answer is A: poor vision. In the 20/80 visual acuity notation, 20 represents the test distance in feet, and 80 represents the line on the eye chart that the patient can read. Therefore, a person with 20/80 vision can only see at 20 feet what a person with normal vision can see at 80 feet. This indicates poor vision as the patient's visual acuity is significantly below normal. Summary: - Choice B (acute vision) is incorrect as 20/80 vision indicates poor vision, not exceptional sharpness. - Choice C (normal vision) is incorrect as 20/80 vision is below normal range. - Choice D (presbyopia) is incorrect as presbyopia is a condition related to aging and difficulty focusing on close objects, not specifically indicated by 20/80 vision.