the eye

Retina

  • Contains photoreceptors

    • Detect light

    • Two types

      • Rodes

        • For black and white vision

      • Cones

        • For coloured objects

        • Found in high concentration in fovea

 

Blindspot

  • No Rodes or Cones

 

Accommodation

  • Ability to adjust its focus in order to see objects clearly at different distances


 

Pupil reflex

  • Reflex action is like an involuntary action

  • Due to change light intensity

  • Parts involved

    • Pupil

    • Radial muscles

    • Circular muscles for the iris

    • The muscles are antagonistic

  • Pupil reflex is when the pupil changes size

Light intensity

Radial muscles

Circular muscle

pupil

Dim light

Contracts

Relax

Enlarges, bigger

Bright light

Relax

Contract

Smaller, constricts, rejects, contract

 

Accommodation

  • It occurs for the eye to focus on objects at different distances

    • Far and near

  • Parts involved

    • Eye lens, ciliary muscles, suspensory ligaments

 

Distance

Eye lens

Ciliary muscles

Suspensory ligaments

far

Thin

Relax

Tightens or taut

near

Thick

Contracts

Loosen or slack

 

  1. Which parts are involved in pupil reflex

  2. How do the parts behave during a pupil reflex

 

 

Photoreceptors

  • 2 types: Rodes and cones

 

  • How are these distributed on the retina

  • Roles of each

    • For the cones, specify types of colour

  • The shape of each