The eye as a sense organ

For this week, we were assigned the following task by our Biology teacher.

  • In pairs,  add a video which shows the pupil reflex in your eyes.
  • Using your reflex actions´knowledge , sketch the sequence of the pupil reflex. State the stimulus, receptors, coordinator, effector, effect, response and all the neurones involved.
  • What is the importance of this reflex?
  • Booklet act: COMPLETE questions 1 b and c on page 9.

1.

2.

  1. Stimulus: bright light
  2. Receptors: cones
  3. Coordinator: brain
  4. Effector: muscles of the iris
  5. Effect: circular muscles,contract and radial muscle, relax
  6. Response: pupil constricts

Neurones involved: Sensory, relay and motor.

  1. Stimulus: low light/darkness
  2. Receptors: rods
  3. Coordinator: brain
  4. Effector: muscles of the iris
  5. Effect: circular muscles, relax and radial muscles, contract
  6. Response: pupil dilates

Neurones involved: Sensory, relay and motor.

3. The importance of this reflex is that it measures the amount of light entering the retina, to prevent it from being damaged.

Biology virtual period: Reflex arcs

Read page 5 from HERE.

  • Act: Answer the interactive question and post a screenshot with the answers.
  • Film 2 examples which show reflex actions. (BE CAREFUL IN USING HOT OBJECTS! MIMICS ARE ACCEPTED!)

For each example, name the structures involved:

stimuli __  receptor __coordinator __effector __ response

Stimuli: Cutting your finger with a knife.

Receptor: The skin.

Coordinator: The spinal cord.

Effector: Tendons in the hand.

Response They contract and move the finger away.

  1. https://youtu.be/2EftrnUyDVA