BiologyCode 5090
Mammalian sense organs
What this topic asks you to be able to do
- outline how sense organs are collections of receptor cells that react to particular stimuli: light, sound, touch, temperature and chemicals
- Identify, on a diagram, these parts of the eye, limited to: cornea, pupil, iris, lens, suspensory ligaments, ciliary muscles, retina, fovea, blind spot and optic nerve
- outline what each part of the eye does, limited to: cornea – refracts light; iris – regulates the amount of light passing into the pupil; lens – brings light to a focus on the retina; ciliary muscles and suspensory ligaments – alter the lens's shape; retina – holds light receptors, some responsive to different colours of light; fovea – has the highest concentration of light receptors; optic nerve – transmits impulses to the brain
- Explain how the pupil reflex responds to light intensity through the antagonistic action of the iris's radial and circular muscles
- Account for accommodation, which lets the eye see nearby and distant objects, by reference to contraction and relaxation of ciliary muscles, tension in suspensory ligaments, lens shape and light refraction