University:
Camosun College
Course:
BIOL 252 | Pathophysiology for Nursing 1
Academic year:

2024
Views:

184

Pages:

2
Author:

Aysha A.

Visual Fields Ganglion Cells: Receive action potentials (AP) when light falls on rods and cones. Bipolar Cells: Directly involved in synapses, acting as excitatory synapses. Horizontal Cells: Involved in synapses, acting as inhibitory synapses. A single ganglion cell has a wide receptive field. On-Centre Off-Surround Ganglion Cells: Centre Stimulation: When light falls on the center of the receptive field, receptor cells directly connect to ganglion cells and activate them, causing the ganglion cell to excite and send an AP. Surround Stimulation: When light falls on the periphery, peripheral receptor cells are excited, horizontal cells are activated, and ganglion cells are inhibited. Light Response: Light on Centre (No Horizontal Cell Activation): Max AP from ganglion cell. Light on Centre + Periphery: Bigger response (increased AP). Light on Periphery: Smallest response (decreased AP). Visual Pathway & Field Defects Temporal Field: Perceived by the nasal retina. Nasal Field: Perceived by the temporal retina. Visual Field & Retina Mapping: Superior Visual Field: Perceived by the inferior retina. Inferior Visual Field: Perceived by the superior retina. In summary, the visual fields are inversely mapped to the retina (superior field to inferior retina and vice versa), and the on-centre off-surround mechanism plays a crucial role in visual processing by modulating ganglion cell activity depending on where the light stimulus falls.