Photoreceptors detect Photoreceptors detect Reflex occurs Reflex occurs Muscles in the Iris are the Muscles in the Iris are the effectors effectors Radial muscles in Iris contract Radial muscles in Iris relax Circulatory muscles in Iris relax Circulatory muscles in Iris contract Pupil diameter opens Pupil diameter closes More light enters the eye Less enters the eye Focusing the eye: Far Object Near Object Incoming light is parallel Incoming light is divergent Ciliary muscles relax Ciliary muscles contract Suspensory ligaments are tight Suspensory ligaments are loose Lens is pulled Lens becomes thin fat is refracted less Light is refracted more Light converges on the retina Light converges on the retina Controlling Skin temperature: Too hot Too cold
Photoreceptors detect Reflex occurs Muscles in the Iris are the effectors Radial muscles in Iris contract Circulatory muscles in Iris relax Pupil diameter opens More light enters the eye Photoreceptors detect Reflex occurs Muscles in the Iris are the effectors Radial muscles in Iris relax Circulatory muscles in Iris contract Pupil diameter closes Less enters the eye Focusing the eye: Far Object Near Object Incoming light is parallel Ciliary muscles relax Suspensory ligaments are tight Lens is pulled thin is refracted less Light converges on the retina Incoming light is divergent Ciliary muscles contract Suspensory ligaments are loose Lens becomes fat Light is refracted more Light converges on the retina Controlling Skin temperature: Too hot Too cold
igcse_biology_revision_book.docx