Rod photoreceptors

From The School of Biomedical Sciences Wiki
Revision as of 14:09, 23 October 2015 by 130055435 (Talk | contribs)
Jump to: navigation, search

Rods are highly specialised, extended cells, that permit vision at low light levels because of the disc filled outer segment. Within the discs is a vast amount of rhodopsin. This visual pigment absorbs dim light best at a wavelength of 495nm. Once the light is received by rhodopsin, the signal is transduced into chemical signals via G-proteins  and a decrease in cGMP  that causes a knock on closure of sodium channels whilst the potassium ions continue to flow out of the cell. The cell membrane now becomes hyperpolarized to -70mv. Therefore, the number of glutamate neurotransmitters released decreases. Rod cells go on to produce a response in the nerve signal pathways to the Optic Nerve via a bipolar and ganglion cell. Rod cells get bleached in high intensities of light.[1]


References

  1. Alberts et al, Molecular Biology of the Cell (2008), Fifth Edition, Garland Science, Pages 917-918.
Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox