sensory mechanisms

Receptor proteins for the neurotransmitter molecules released by rods and cones are found on A bipolar cells. B lateral cells. C ganglion cells. D retinal cells. E amacrine cells

A

The _____ is the region of the eye where photoreceptors are most highly concentrated. A lens B fovea C optic nerve D pupil E sclera

B

The blind spot in the human retina is the location that has the collected axons of A optic chiasma. B ganglion cells. C primary visual cortex. D bipolar cells. E lateral geniculate nuclei.

B

What name is given to the opening that allows light into the interior of the eye? A sclera B pupil C ligament D optic nerve E retina

B

Which of the following statements about photoreception is true? A Rod cells are responsible for color vision. B The retinal molecule changes shape when it absorbs light. C Cone cells are sensitive to dim light. D Rhodopsin is found in cone cells.

B

Which part of the eye bends light to focus it on the retina? A Sclera. B Lens. C Fovea. D Optic nerve.

B

Which part of the eye contains the densest concentration of cone cells? A Lens. B Fovea. C Opsin. D Cornea.

B

It can be very difficult to select an angle for sneaking up to a grasshopper to catch it because grasshoppers have A binocular vision. B eyes with multiple fovea. C compound eyes with multiple ommatidia. D a camera-like eye with multiple fovea. E excellent hearing for detecting predators.

C

The correct sequence of sensory processing is A stimulus reception → sensory perception → sensory adaptation → sensory transduction. B sensory adaptation → stimulus reception → sensory transduction → sensory perception. C stimulus reception → sensory transduction → sensory perception → sensory adaptation. D sensory perception → stimulus reception → sensory transduction → sensory adaptation. E sensory perception → sensory transduction → stimulus reception → sensory adaptation.

C

Which part of the eye is the opening through which light initially passes? A Sclera. B Fovea. C Pupil. D Retina.

C

A given photon of light may trigger an action potential with thousands of times more energy because the signal strength is magnified by A a G protein. B sensory adaptation. C the receptor. D an enzyme-catalyzed reaction. E triggering several receptors at once

D

A rod exposed to light will A undergo a graded depolarization that will increase its release of glutamate. B undergo a graded hyperpolarization that will increase its release of glutamate. C fire action potentials that will increase its release of glutamate. D undergo a graded hyperpolarization that will decrease its release of glutamate. E undergo a graded depolarization that will decrease its release of glutamate.

D

The _____ changes shape to focus light on the retina. A vitreous humor B blind spot C cornea D lens E optic nerve

D

What name is given to the tough layer that forms the "white" of the eye? A blind spot B choroid C fovea D sclera E aqueous humor

D

Which of the following statements does not describe a vertebrate eye? A It acquires images by focusing light on receptor cells. B It contains photoreceptors that are either rod- or cone-shaped. C It contains cells that are sensitive to either dim light or color. D It contains many light-sensing columns called ommatidia.

D

Rods exposed to light will A hyperpolarize due to the closing of potassium channels. B depolarize due to the opening of sodium channels. C fire one action potential for each photon received. D depolarize due to the opening of potassium channels. E hyperpolarize due to the closing of sodium channels

E

True or false? Cone cells are color photoreceptors that use different retinal molecules to absorb different wavelengths of light. True False

False

True or false? The "blind spot" in vertebrate eyes is a region of the retina that contains no photoreceptors. True False

True

photoreceptor

a molecule, cell, or organ that is specialized for the detection of light

cones

a photoreceptor cell in the retina with a cone-shaped outer portion; partially sensitive to bright light of a certain color (blue, red, or green)

rods

a photoreceptor cell in the retina with a rod shaped outer portion; partially sensitive to dim light but its not used to distinguish color

fovea

a small region of the retina in which the photoreceptors are very tightly packed, producing the most acute vision

Retina

a think layer of light-sensitive cells (rods or cones) and neurons at the back of a camera-like eye, such as the eyes of vertebrates and cephalopods

opsin

a transmembrane protein involved in animal vision. joins with retinal to form a light-detecting pigment

perception

colors, smells, sounds, and tastes- are constructions formed in the brain and do not exist outside of it

sensory adaption

decrease in responsiveness; enables you to see, hear, and smell changes in the environment that very widely in stimulus intensity

sensory receptor

describes a sensory cell or organ, as well as the subcellular structure that interacts directly with stimuli; many detect stimuli from outside the body (heat, light, pressure) but also inside the body (blood pressure, body position)

lens

highly transparent lens-shaped or nearly spherical body in the eye that focuses light rays onto the retina

retinal

molecule that together with opsin, forms rhodopsin, the light-detecting pigment of the rod cells in animal eyes

sensory cells

most are specialized neurons or epithelial cells, some exist singly, and others are collected in sensory organs (eyes and ears)

receptor potential

the change in membrane potential itself; magnitude varies with the strength of stimulus

sensory transduction

the conversion of a physical or chemical stimulus to a change in the membrane potential of a sensory receptor

sensory reception

the detection of a stimulus by sensory cells

amplification

the strengthening of a sensory signal during transduction

cornea

the transparent sheet of connective tissue at the very front of the eye in vertebrates and some other animals. the cornea protects the eye and focuses light onto the retina