PSYC 1300 - Chapter 5.4

what is the most used sense

vision

describe how we see (use 3 main vocab words)

light passes through the cornea (eyes thick transparaent outer layer)

light then enteres the lens where light is bent and focused to form an image on the

retina, which is the thin inner surface of the back of the eyeball

what is the retina

where light is focused onto

thing inner-surface of eye

back of the eye

contains sensory receptors

transduces light into neural signals

what is the pupil, what does it contrl

small center of eye, controls how much light enters

what is the iris and what does it do

small circular muscle that determines the eye’s color and controls the pupil’s size

what is accomodation

the process of flattening eyes to focus on distant objects and thickening eyes to focus on closer objects

what is presbyopia

a condition where the lens hardens → difficult to focus on close images

the retina has two types of sensory receptor cells: ____ which do ____ and ____ which do _____

rod responds to lower levels of lights and does not do color

cone responds to higher levels of light and does color

what is the fovea

center of retina, where cones are packed

where are the rods packed

along the edges of the retina

what are phootpigments

protein muscles that become unstable and split apart when exposed to light

rods and cones (do/do not) fire action potentials like other neurons. Explain

instead, the decomposition alters the membrane potential and triggers action potentials in neurons downstream

describe what happens when light hits the retina (include: rods/cones, photopigments, ______ cells)

light hits retina → hits either cone/rod → inside, photopigment is destroyed → action potential fired in neuron downstream → middle helpers clean message → organized message reach special messenger cells called ganglion cells. these are the very first cells in the chain that shoot action potentials down axons

what are ganglion cells

first neurons in the visual pathway with axons

the ganglion cells send their signals along their axons from inside the eye to the __________, which exits the eye at the back of the retina.

optic nerve

what is the optic nerve

receives axons bundled at the back of retina from ganglion cells, point where it is has no rods or cones → blind spot

what is the optic chiasm

crossing point of nerve fibers (creates left FOV goes to right and right FOV goes to left)

what is the dorsal stream and where does it project to

projects to parietal lobe and is specialized for spatial perception (“where” stream)

what is the ventral stream and where does it project to

projects to the temporal lobe and apperas to be specailized for the perception and recognition of objects, such as determinig their colors and shapes (“what” stream)

what is object agnosia

inability to recognize objects