The eyes

• What is the main focus of today's video?

  The structure of the eye and iris reflex
• What does a cross section of the eye show?

  A view of the inside of the eye
• What is the first structure light hits when entering the eye?

  The cornea
• Why is the cornea transparent?

  To allow all light to pass through
• How does the cornea obtain oxygen?

  By diffusion from the outside air
• What is the function of the cornea?

  To refract or bend light
• What is the colored part of the eye called?

  The iris
• What does the iris control?

  The size of the pupil
• What is the pupil?

  A gap in the middle of the iris
• What is the role of the lens in the eye?

  To refract light and change shape
• How does the lens help focus light?

  By changing its shape
• What is the retina made up of?

  Two types of receptor cells
• What are cone cells sensitive to?

  The color of light
• Why can't we see colors in low light?

  Only rod cells are active
• What do rod cells allow us to see?

  In black and white
• What is the fovea?

  A spot on the retina with cone cells
• What is the function of the optic nerve?

  To transmit impulses to the brain
• What happens to the pupil in bright light?

  It constricts to reduce light intake
• What is the purpose of the iris reflex?

  To protect the retina from damage
• What are the two types of muscles in the iris?

  Circular and radial muscles
• How do circular muscles affect the pupil?

  They contract to make it smaller
• What do radial muscles do when it's dark?

  They contract to open the pupil
• What are the steps of the iris reflex in response to light intensity?

  • In bright light, circular muscles contract
  • Pupil constricts to reduce light intake
  • In low light, circular muscles relax
  • Radial muscles contract to dilate pupil
• What are the differences between cone cells and rod cells?

  Cone Cells:

  • Sensitive to color
  • Function well in bright light

  
  

  Rod Cells:

  • Sensitive to light intensity
  • Allow vision in black and white
• What is the overall function of the eye's structures?

  • Refract light to focus on the retina
  • Protect the retina from excessive light
  • Transmit visual information to the brain
• What is the process of accommodation in the eye?

  It changes the lens's refractive power
• Why do glasses help with accommodation issues?

  They provide additional refracting power
• Which parts of the eye are important for accommodation?

  Cornea and lens
• What role do the ciliary muscles play in accommodation?

  They control the shape of the lens
• What is the fovea in the eye?

  It is the spot where light is focused
• How does the cornea contribute to vision?

  It refracts light to focus on the fovea
• What happens to light rays from distant objects?

  They are almost parallel when hitting the eye
• What shape does the lens take for nearby objects?

  It becomes short and fat
• What happens to the ciliary muscle when focusing on nearby objects?

  It contracts and moves inward towards the lens
• What do the suspensory ligaments do during accommodation?

  They slacken when the ciliary muscle contracts
• What is the effect of the ciliary muscle relaxing?

  It stretches the lens to reduce curvature
• What is long-sightedness?

  Inability to focus on nearby objects
• How do convex lenses help long-sighted individuals?

  They provide extra refracting power
• What is short-sightedness?

  Inability to focus on distant objects
• How do concave lenses assist short-sighted individuals?

  They counteract over-refraction of light