visual pathway

Question 1

field of vision

Answer 1

• 100 degree temporally
• 60 degree nasally
• 120 degree central (binocular vision)
• 60 degree superiorly
• 75 degree inferiorly

Question 2

parts that makes up the visual pathway

Answer 2

1. Retina
2. Optic Nerve
3. Optic Chiasma
4. Optic tract
5. Lateral geniculate body
6. Optic radiation
7. Visual cortex

Question 3

optic chiasma

Answer 3

• Fibres from the nasal half of the retina decussate (cross the midline) at the optic chiasm and cross to the opposite optic tract
• Fibres from the temporal half of the retina do not cross but pass back into the optic tract of the same side
• This partial crossing is essential for binocular vision

Question 4

optic tract

Answer 4

• The tracts are derived from the nasal nerve fibres from the opposite side and the temporal nerve fibres from the same side of the retina
• The tract runs lateral and backwards from the chiasma

Question 5

visual cortex

Answer 5

• The optic radiation goes to the visual cortex
• The visual cortex forms the bulk of the occipital lobes in the brain
• Visual cortex:
  > Primary visual cortex (striate cortex)
  > Secondary visual cortex

Question 6

visual cortex’s nerve cells & their receptive field

Answer 6

• Different classes of cells that respond, not to a point of light, but to bars of light and their orientation
• 3 types of cells:
  > Simple
  > Complex
  > Hypercomplex
• Receptive fields as mapped out in the cortex differs from those in the retina; without the concentric circularly symmetrical pattern