The human eye contains specialised structures that allow it to focus light and adjust to different environmental conditions.
Label structures X, Y, and Z on the diagram of the eye.
Choose from the words in the box below:
[cornea, iris, optic nerve, pupil, sclera]
- X: ______
- Y: ______
- Z: ______
When a person shifts their gaze to focus on a near object, the incoming light rays must be refracted more by the lens. How does the lens change to refract light more?
- By becoming thicker and more curved
- By becoming thinner and flatter
- By becoming entirely opaque
Which two structures directly control the shape and curvature of the lens during accommodation?
- Ciliary muscles
- Iris
- Pupil
- Retina
- Suspensory ligaments
Name the specialized pathway of sensory neurones that transmits electrical impulses from the retina to the brain.
When a person walks into a very bright room, their pupil reflexively constricts to prevent damage to the photoreceptors. The sequence below shows the pathway of this pupil reflex action:
- Stimulus: High light intensity
- Receptor: ________
- Coordinator: ________
- Effector: ________
- Response: Pupil constricts
Complete the sequence by selecting the correct word from the box below for each of the boxes 2, 3, and 4:
[brain, ciliary muscle, iris muscles, optic nerve, retina]
- Receptor (2): ________
- Coordinator (3): ________
- Effector (4): ________