chapter 9 Flashcards
Vision Significance
Animals depend on vision to identify nourishment, poison, and potential mates. It’s an essential sensory system for survival.
Human Eye vs. Camera
The human eye is similar to a camera but superior in many ways. It can adapt to various light conditions, focus quickly, and has a wider dynamic range
what is the Retina
the retina is the innermost layer of the eye containing photoreceptor cells that convert light energy into neural signals for vision.
what are Photoreceptors
Photoreceptors detect differences in light intensity. They include rods for low-light vision and cones for color vision in bright light.
what is the Lateral Geniculate Nucleus (LGN)
The LGN is the first synaptic relay in the primary visual pathway, transmitting visual information from the retina to the visual cortex.
what are the Properties of Light
Light is electromagnetic radiation with properties like wavelength, frequency, and amplitude. It’s studied in optics, which explores its interactions like reflection, absorption, and refraction.
anatomy of the Eye
The eye’s anatomy includes the pupil (where light enters), sclera (white of the eye), iris (gives color), cornea (transparent surface), and optic nerve (transmits visual information to the brain).
what is Refraction by the Cornea
The cornea bends light to focus it on the retina, forming clear images. It’s like the lens of a camera.
what is Accommodation by the Lens
The lens changes shape to focus on objects at different distances, allowing for clear vision.
what is the Pupillary Light Reflex
This reflex adjusts the size of the pupil based on ambient light levels, similar to how a camera aperture adjusts to control light.
what is the Visual Field
The visual field is the space viewed by the retina when the eye looks straight ahead, crucial for spatial perception
what is Visual Acuity
Visual acuity is the ability to distinguish two nearby points and is measured in degrees using visual angles
what is the Microscopic Anatomy of the Retina
The retina contains photoreceptors like rods and cones, which process light signals and transmit them to the brain for interpretation
what is Phototransduction
Phototransduction is the process by which photoreceptors convert light energy into neural signals, crucial for vision
what is Retinal Processing
involves complex interactions between photoreceptors, bipolar cells, and ganglion cells to process visual information before transmission to the brain.
what is Ganglion Cell Output
Ganglion cells are the only cells in the retina that produce action potentials, carrying visual information to the brain
what is Parallel Processing
Parallel processing in the retina involves simultaneous input from both eyes, which is compared in the cortex for depth perception and object recognition
what are Light Properties
Light is electromagnetic radiation with properties such as wavelength, frequency, and amplitude. Its energy is proportional to frequency, with high-energy examples like gamma radiation and cool colors, and low-energy examples like radio waves and warm colors
what is the Anatomy of the Eye (Continued)
The anatomy of the eye also includes the fovea, a pit in the retina with the highest concentration of cones, maximizing visual acuity in the central visual field.
what is Phototransduction in Rods
Phototransduction in rods involves light interacting with photopigments to produce a change in membrane potential, leading to hyperpolarization in response to light
what is Phototransduction in Cones
Phototransduction in cones is similar to rods but with different opsins for color vision. They contribute to color detection and spectral sensitivity according to the Young-Helmholtz trichromacy theory of color vision.
what are the Regional Differences in Retinal Structure
Retinal structure varies from the fovea to the periphery, with the peripheral retina having a higher ratio of rods to cones and being more sensitive to light. The fovea has a 1:1 ratio of cones to ganglion cells, maximizing visual acuity.
what is Dark Adaptation
Dark adaptation involves the dilation of pupils, regeneration of unbleached rhodopsin, and adjustments in functional circuitry to improve vision in low-light conditions.
what is Calcium’s Role in Light Adaptation
Calcium concentration changes in photoreceptors regulate light adaptation by modulating cGMP-gated sodium channels, indirectly affecting levels of cGMP and the responsiveness of photoreceptors to light.
