A + P Lab Nervous System Flashcards
what causes the blind spot
optic disc is located in that area on the retina
-no photoreceptors and therefore cannot detect photons of light
in this experiment when the light becomes focused momentarily on the optic disc you temporarily lose sight of the object
what determines visual acuity
light is focused onto the retina
shape of the cornea, lens, and eyeball affect how light is focused through the lens onto the retina
why is light focused behind the retina
-result
eyeball is taller than longer or the cornea is too flat (farsighted)
-can see things far away but not close up
why is light focused in front of the retina
-result
eyeball is longer than taller or the cornea is too round
-nearsighted
anatomy of the eye and vision physiology involved in correctly identifying the numbers in the colored bunches of dots
the retina has cones and rods
- three types of cones
- -each detect different wavelengths of color
- if all cones work correctly you can perceive differences in color
- if not then one or more types of cones nay not be sensitive/receptive to the specific wavelengths of color presented in a specific dot combination
what causes the hole in your hand illusion
each eye presents a unique visual image to the visual cortex in the occipital lobe
- within that cortex the two images received by L & R eyes are “stitched” together to create a single image
- when each is presented with a different image the visual cortex stitches the images into one
- here it superimposes a hole into your hand
why did eyes closed and head back produce the most swaying?
- inner ear provides sensory input on balance and equilibrium
- vision provides sensory input that can corroborate the input received by the inner ear
- if you remove the vision input, the only major input for balance is the inner ear, so more swaying may be induced
- when you remove vision and tilt the head, you are still reliant on the inner ear for balance
- -endolymph in the anterior semicircular canal begins stimulating the hair cells within the ampulae
effect of endolymph movement on balance
stimulated hair cells are often not stimulated while standing upright, so the auditory cortex has to rectify this information with the information already known about position (memory and proprioceptors)
due to this mismatch the body sways a little more than normal
what causes the nystagmus when spinning?
when you spin laterally the movement of endolymph within the lateral semicircular canals stimulates the hair cells in the ampullae
- when this information is received processed by the cerebral cortex, it results in “tracking ahead” (vestibular nystagmus) by the eyeballs in an attempt to maintain balance
- your eyes pick a point within the visual field to focus on as long as possible
- -when you spin past your eyes pick a new object
- when you stop spinning the endolymph within the lateral semicircular canals continues to move and stimulate the hair cells, so the cerebral cortex thinks you are still spinning and consequently tells the eyes to continue “tracking ahead”
why are you able to follow some scents better than others
leading factor
- freshness of trail
- -smells are molecules being released from an object
- wetness
- -the wetter the object is the more molecules that are released so the smellier it is
other factors that influence your ability to smell an object
how sensitive your own olfactory receptors are to specific chemicals
how much mucous is on top of the olfactory epithelium
-too much means it will be harder for chemicals to reach the receptors
the density of working olfactory receptors in your nasal area
why do strong smells bring back memories
olfactory information bypasses the thalamus and goes straight to the hypothalamus, which is seated within the limbic system
-since the limbic system controls our emotions and is linked with memory, the unfiltered smell information can elicit a very strong emotion
what affects your ability to identify foods regarding taste and smell
the nasopharyngeal tract shares gustatory and olfactory receptors
-food/drink can stimulate both types of receptors
gustatory information received in the gustatory cortex is often processed tandem with olfactory info received in the adjacent olfactory cortex
when both sets of information are processed together, food/drinks taste “fuller”
when only one set of info is processed, food/drinks taste blander
locations of five taste sensations
sweet: tip of tongue
salty: tip of tongue
bitter: middle of tongue
sour: middle/rear of tongue
umami/savory: back of tongue
why are these areas most receptive
there are more sensitive receptors for these tastes in these areas
you should be able to taste all five in most areas
