The Special Senses: Vision

The following list contains many of the structures that light must pass through to reach the rods and cones. Place the structures in order that light would pass through them.

• Cornea

• Bipolar Neurons and Ganglion Cells

• Vitreous Humor (Gel Filled Posterior Cavity)

• Lens

• Aqueous Humor (Liquid Filled Anterior Cavity)

Once light is absorbed, what is the path of the nervous signal?

• Rod or Cone --> Bipolar Neuron --> Ganglion Cell --> Optic Nerve

• Rod --> Cone --> Ganglion Cell --> Bipolar Neuron --> Optic Nerve

• Pigmented Layer --> Rod or Cone --> Bipolar Neuron --> Ganglion Cell

Which part of the neural layer continues into and becomes the optic nerve?

• Rods

• Cones

• Bipolar Neurons

• Ganglion Cells

Different animal species differ in the relative number of rods and cones that are present in their eyes. Which of the following statements would you expect to be true about these differences?

• Nocturnal (active at night) species will have relatively more rods in their eyes; diurnal (active in the day) species will have relatively more cones.

• 
  Species that require better depth perception will have relatively more cones in their eyes; species that require greater field of vision will have more rods.

• 
  Nocturnal (active at night) species will have relatively more cones in their eyes; diurnal (active in the day) species will have relatively more rods.

Which of the following statements is true for cones?

• There are more cones than rods in the retina.

• 
  They are specialized for low light vision.

• 
  They are concentrated in the center of the retina.

• 
  They are named for their long cylindrical shape.

True or False: if false, choose the answer that corrects the statement.

Waves of light must pass through both the ganglion and pigmented cells before reaching the photoreceptors.

• False, light reaches the photoreceptors first.

• False, light must pass through the ganglion cells, but not the pigmented cells.

• True

What is the difference between special senses and general senses?

• 
  Special senses are located in special sense organs, while general senses are distributed throughout the body.

• 
  General senses include sight, taste, and equilibrium; special senses include pressure, temperature, and pain.

• 
  The receptors for general senses are receptor cells, while special senses use modified nerve endings.

Which of the following correctly matches the sense to the type of stimulus it measures in the environment?

• 
  Electromagnetic radiation: Smell.

• 
  Pressure waves traveling through a fluid: Hearing.

• 
  Chemical properties of gasses dissolved in a liquid: Equilibrium.

• 
  Movement and gravity: Sight.

Identify the layer of the eye that function to protect the eye.

• 
  Fibrous Layer.

• 
  Vascular Layer.

• Neural
  Inner Layer.

Which structure(s) of the middle layer contains muscles?

• 
  Iris & ciliary body.

• 
  Iris only.

• 
  Choroid & ciliary body.