biology a level help ??!

can people explain to me the process of rods/cones and retinal convergence??

I have no clue how it all works.

Thank you x

Reply 1

OxFossil

19

That's a whole essay! Here's an overview:

Basically, the rods are distributed all over the retina (except at the fovea), and share the ganglions that connect to the optic nerve - about 15 to 30 rods share each ganglion. This is called convergence (because a whole load of rods converge into one ganglion). But the cones - which are found at the fovea - have a ganglion each. Here is a picture!

How it works is:

1. light falls on the photosensitive (pigmented) epithelial cells at the back of the retina
2. This causes the pigment (rhodopsin) contained in those cells to change into opsin
3. This results in a change in the neural cell membranes and neurotransmitter release
4. The signal caused by the light stimulus travels via the rod (or cone), to the bipolar cell, and then to the ganglion cells.

Does that help?

Reply 2

lqwerty98

OP

4

Original post by OxFossil

That's a whole essay! Here's an overview:

Basically, the rods are distributed all over the retina (except at the fovea), and share the ganglions that connect to the optic nerve - about 15 to 30 rods share each ganglion. This is called convergence (because a whole load of rods converge into one ganglion). But the cones - which are found at the fovea - have a ganglion each. Here is a picture!

How it works is:

1. light falls on the photosensitive (pigmented) epithelial cells at the back of the retina
2. This causes the pigment (rhodopsin) contained in those cells to change into opsin
3. This results in a change in the neural cell membranes and neurotransmitter release
4. The signal caused by the light stimulus travels via the rod (or cone), to the bipolar cell, and then to the ganglion cells.

Does that help?

really helpful, thank you so much