Questão | Responda |
Which muscles control the lens of the eye? | Ciliary muscle. |
What connects the ciliary muscle with the lens? | zonule fibers |
Normal sight = | emmetropia |
Nearsighted = | myopia |
Farsighted = | hyperopia |
To focus on closer objects, the ciliary muscles have to | contract |
T/F: Photoreceptors and bipolar cells are neurons. | F. They both do NOT produce AP. |
Photoreceptors are (depolarized/ hyperpolarized) by light. | Hyperpolarization |
T/F: Photoreceptors follow a all-or-none hyperpolarization. | F. It is graded based on intensity of light. |
When it is dark, ____ and ____ ions can flow into the rods due to presenting ______. | Sodium and calcium cGMP |
In the light, cGMP is reduced _______ and ______ flow is blocked, pushing the rod into a ________ state. | sodium and calcium. Hyperpolarized state. |
The discs in the rods contain light sensitive proteins _______, which start a cascade that (closes/opens) the sodium/calcium channel. | Rhodopsin closes |
What happens at the molecular level on opsin? | light --> changes in configuration of opsin --> allowing closing of calcium and sodium channels. |
Rods and cones are very different photoreceptors. The rods integrate (high/low) accuracy light stimuli, and are good for __________ conditions. | Rods: low light and low accuracy. |
Which is more specific? cones or rods? | Cone |
Which is better for color detection? | Cones |
T/F: there are no rods at the fovea. | T. |
To differentiate color, cones also have very special gitfs Thri coor od detction are: | red green blue |
cell bodies of optic nerve are the | ganglion cells |
The (central/off-center ) ganglia cells are more active when the picture is brighter in the middle. | central |
Ganglion cells that prefer 'center brighter than edge' are called _______ while those in favor of 'the periphery brighter than center' are called _____. | on-center ganglion cells Off-center ganglion cells |
The mGluR6 are ______ receptors | glutamate |
On- and off center is determined in _______ | connection to bipolar cells and ganglion cells |
center cone cell is connected to _______ and _______ bipolar cells, which in turn are connected to ______ and ______ ganglion cells. | on-center and off-center bipolar cells on-center and off-center ganglion cells |
match the glutamate receptors with type of bipolar cells 1) mGluR6 2) AMPA kainate | mGluR6: inhibitory (depolarization), on-center AMPA kainate: excitatory (hyperpolarization), off-center |
Types of glutamate receptors on ganglion cells. | AMPA kainate, NMDA (all excitatory) |
Describe the downstream effect of light shining on central cone. | 1. cone is HYPERpolarized 2. more glutamate 3. on-center bipolar cells are depolarized --> increased firing rate of on-center ganglion cell 4. off-center bipolar cells are hyperpolarized --> decreased firing rate of off-center ganglion cell |
Order of visual cortex mapping from the most distal to most central. | monocular portion -- binocular portion -- macula |
The _____ has the largest cortical representation. | fovea |
T/F: V1 represents edges moving in different directions. | T. |
V1 has a spacial map of the movement of edges in different orientations in a _______ structure. | pinwheel |
The dorsal stream is the wh___ detector of vision. It goes from V1 to ____ to _____. | where. V1 - V2 - MT |
The ventral stream is the wh___ detector of vision. It goes from V1 to ____ to _____. | what. V1 - V2 - V4 |
Three types of involuntary eye motion are | drifts, tremor, microsaccades |
T/F: neuron firing rate at a constant object is constant. | F. It will adapt and become less active. |
Three eye movements maintaining the direction of gaze are | 1. saccades, 2. smooth pursuit 3. vergence |
Two eye movements maintaining the stabilization of gaze are | 1. vestibulo-ocular reflex 2. optokinetic reflex |
Saccades are (voluntary/ involuntary) while microsaccades are (voluntary/ involuntary). | Saccades: voluntary. Microsaccades: involuntary. |
T/F: smooth pursuit is usually initiated with a catch-up saccade | T. |
Disconjugate is required for ________ | vergence |
Neurons that fire when an image is in a certain location in the visual field are near neurons that ________. This is represented in the ________. | move the fovea to the location. Represented in the superior colliculus. |
Neurons in the substantia nigra inhibit eye movement via the ___________. | Superior colliculus. |
T/F: Neurons in the parietal cortex represent the location of saccade targets but are not focused on the target. | T. (easily distracted. |
Frontal eye field is more focused on the _______ of the saccade. | motor action |
Which additional part of the brain controls smooth pursuit? | striate cortex -- middle temporal and medial superior temporal -- frontal eye fields dorsolateral pontine nuclei -- vestibular nuclei -- flocculus and vermis of the cerebellum |
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