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Zorluk: ZorNervous Coordination and Sense Organs

When an individual transitions from focusing on fine print in a brightly lit room to viewing a distant star in the night sky, which combination of ocular physiological changes occurs to adjust focal length and light entry?

  1. Ciliary muscles relax, suspensory ligaments become taut, and radial iris muscles contract.Cevap
  2. B
    Ciliary muscles contract, suspensory ligaments become slack, and circular iris muscles contract.
  3. C
    Ciliary muscles relax, suspensory ligaments become slack, and radial iris muscles contract.
  4. D
    Ciliary muscles contract, suspensory ligaments become taut, and circular iris muscles contract.

Cevap

Ciliary muscles relax, suspensory ligaments become taut, and radial iris muscles contract.
For distant vision, the ciliary muscles relax, causing the suspensory ligaments to become taut and pull the lens into a flatter shape. Simultaneously, under dim light conditions such as looking at the night sky, the radial iris muscles contract under sympathetic control to dilate the pupil and maximize light capture.

Adım Adım Çözüm

1
Analyze accommodation for distant vision
For distant vision, the ciliary muscles relax, widening the ciliary body ring. This increases tension on the suspensory ligaments (making them taut), pulling the lens into a flatter, less convex shape to increase focal length.
Distant light rays require less refraction to focus accurately onto the retina.
2
Analyze pupillary reflex for low light conditions
In dim light (viewing a night sky), sympathetic nerve impulses stimulate the radial muscles of the iris to contract while circular muscles relax, dilating the pupil.
Pupillary dilation maximizes light entry into the eye under low ambient illumination.
3
Synthesize the combined physiological response
Combining distant accommodation and dim light adaptation yields relaxed ciliary muscles, taut suspensory ligaments, and contracted radial iris muscles.
Lens curvature adjustments and pupil aperture modifications occur concurrently when shifting focus and ambient lighting.

Anahtar Kavram

Visual accommodation and pupillary light reflex mechanisms in the human eye
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Nervous Coordination and Sense Organs

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