The biological structure shown is part of one of the systems in the body - HSC - SSCE Biology - Question 31 - 2014 - Paper 1

1. The stimulus activates the receptor cells.
2. Receptor cells send messages through sensory neurons to the brain.
3. The brain processes the information and coordinates a response to the stimulus.

1. Sound energy in the air enters the outer ear (pinna).
2. Energy transformation occurs as sound waves vibrate the eardrum.
3. Mechanical energy is transmitted through the ossicles (ear bones).
4. This mechanical energy moves the oval window, generating waves in the cochlear fluid.
5. The fluid movement transforms into electrochemical energy in the auditory nerve.

There are two main types of photoreceptors: rods and cones.

• Rods:

  • Responsible for vision in low light conditions (scotopic vision).
  • Do not detect color.
  • High sensitivity to light but low spatial acuity.

• Cones:

  • Function best in bright light conditions (photopic vision).
  • Responsible for color vision and visual acuity.
  • Three types exist, each sensitive to different wavelengths (red, green, blue).

The combination of these two cell types allows humans to adapt to various lighting conditions and perceive a wide range of colors, enhancing overall vision.