Download BIOL 4310 EXAM 1 2025: Sensory Transduction, Psychophysics, and Light Measurement and more Exams Biology in PDF only on Docsity!
BIOL 4310 EXAM 1 2025 WITH 100% ACCURATE
SOLUTIONS
What dimensions does environmental info consist of? - CORRECT - 1. spatial info- the 3 cardinal directions (x, y, and z)
- temporal info- time What are the basic assumptions of this class? - CORRECT - 1. our brain defines who we are
- our reality is based off our perception of the world, which is based upon sensory systems
- Sensory systems are defined by evolution, and have evolved to provide us an adaptive advantage What's a tyto alba, and what external specializations does it use to discriminate sensory info? - CORRECT - barn owl; facial ruff and asymmetrical ears transduction - CORRECT - conversion of one form of energy to another
steps of sensory transduction - CORRECT - 1. info from environment is gathered and conditioned through external specializations
- transducer is activated
- transduction cascade is activated
- ion channels activated
- change in ion concentration
- change in membrane potential
- neural signal where does stimulus coding occur? - CORRECT - when theres a change in membrane potential Whats the advantage of ionotropic channels over metabotropic? Vice versa? - CORRECT - ion channels- faster, greater capacity for signal integration and gain control metabotropic- allow signal amplification and other forms of signal modulation receptor/generator potential - CORRECT - depolarization in primary neuron
4 general classes of channels - CORRECT - 1. non gated (ligand) potassium channels
- non gated sodium channels
- voltage gated potassium channels
- voltage gated sodium channels Is the activation threshold stable? - CORRECT - no Are voltage gated channels open at rest? - CORRECT
- no noise - CORRECT - random unwanted perturbation to a wanted signal whats a way to reduce noise? increase noise? - CORRECT - reduce- CCD increase- increasing sensory receptor molecules What is stochastic resonance? - CORRECT - amplification of subthreshold signals by the addition of noise
- good for rhythmic signals and oscillatory systems
psychophysics - CORRECT - branch of psychology concerned with quantitative relations between physical stimuli and their psychological effects Fechner's Law - CORRECT - a logarithmic (geometric) increase in stimulus intensity is translated as a linear increase in sensation intensity (arithmetic) equation of fechner's law - CORRECT - S=k log R s= psychological sensation R= physical stimulus k= constant Weber fraction - CORRECT - delta I/I = K delta I= difference threshold I- stimulus intensity K= constant
Whats the relationship between wavelength, frequency, and energy? - CORRECT - inverse- as wavelength increases, frequency and energy decrease What's the visible range of light? - CORRECT - 10^15 Hz What type of light is right below visible light on the EM spectrum? Right above? - CORRECT - below- infrared above- UV What are the 2 ways to measure light? - CORRECT - photometry and radiometry radiometry - CORRECT - measurement of optical radiation, which is EM radiation between 3x10^11 to 3x10^ Hz What is radiance? Whats its units? - CORRECT - brightness
Jxs^-1x steradian^-1 or W x steradian^- 1 Which measurements have a directional component? - CORRECT - radiance and luminance Whats irradiance? What's it measured in? - CORRECT - the flux of radiant energy per unit area (intensity) Jxs^-1x cm^-2 or watt (W) x cm^- 2 How many steradians are in a sphere? - CORRECT - 4 pi, or 12.57 steradians photometry - CORRECT - measurement of light, as defined as EM radiation thats detectable by human eye restricted to wavelengths between 360- 830 What are the units for luminance? - CORRECT - lumen x steradian ^-1 or candela
green cone- 533 red cone- 564 rod- 498 which cone is a bit of a misnomer? why? - CORRECT
- red, its in the range of yellow light What are ways you can test if light has an effect? - CORRECT - 1. behavioral
- electrophysiological- using an electroretinogram
- biochemical spectral sensitivity - CORRECT - what wavelengths of light are causing the response action spectrum analysis - CORRECT - graph of the rate of biological effectiveness plotted against a wavelength of light type of fluence response curve
Microspectrophotometry - CORRECT - A technique for measuring, at various wavelengths, the quantity of light reflected or absorbed by a solid or liquid material; used to measure the sensitivity of photopigments in a photoreceptor basic components of biological photosensors - CORRECT - 1. external specializations
- light sensitive tissue sclera - CORRECT - white part of the eye, allows us to communicate emotions to each other muscles of the iris and what they do - CORRECT - 1. sphincter pupillae- contract and pupil constricts (part of parasympathetic NS)
- dilator pupillae- muscle contracts and pulls on sphincter, causing pupil to dilate (part of sympathetic NS) lens - CORRECT - fine tunes the image on the retina
retinula - CORRECT - group of elongate neural receptor cells forming part of the compound eye chromophore - CORRECT - an atom or group whose presence is responsible for the color of a compound ex: retinal melanophore - CORRECT - pigment cell containing melanin found in skin of frogs and other animals how are melanophores photoreceptors? - CORRECT
- when you shine a light on them, the melanin- containing melanosomes disperse throughout the cell photopigment - CORRECT - light absorbing protein ex: opsin
opsin - CORRECT - generally considered members of GPCRs, but not all activate a g-protein 7 major groups rhosopsin - CORRECT - opsin and retinal, which are linked via a schiff base what does retinal consist of - CORRECT - b-ionone ring and retinyl chain what are the 3 general classes of opsins and where are they found? - CORRECT - 1. exclusive photosensory- invert and vert
- exclusive photoisomerase- vert
- photosensory/photoisomerase- mainly invert exclusive photosensory opsin - CORRECT - found in invertebrates and vertebrates its 11-cis retinal is converted to all trans, activating a second messenger system
what the relationship of position of eyes on head and crossover?
- CORRECT - the more centrally located, the less visual crossover there is Where do images from the right visual field go? left? - CORRECT - right- left LGN left- right LGN layers of the retina - CORRECT - 1. OLM
- ONL
- OPL
- INL
- IPL
- GCL
- ILM whats in the ONL? whats its thickness? - CORRECT
- cell bodies of rods and cones same thickness throughout
whats in the INL? whats its thickness? - CORRECT
- cell bodies of interneurons thicker in central than peripheral because of cone bipolar cells whats the OLM formed from? - CORRECT - adherens junctions between muller cells and photoreceptor cell inner segments whats in the ILM? - CORRECT - muller cell endfeet whats in plexiform layers? - CORRECT - synaptic contacts between cell types pedicle - CORRECT - synaptic terminal of cones spherule - CORRECT - synaptic terminal of rods muller cells - CORRECT - radial cells of the retina, span the entire retina
what part of the retina does 99% of vision? - CORRECT - the fovea bipolar cells - CORRECT - cell body in the INL, axon in the IPL connect rods and cones to ganglion cells horizontal cells - CORRECT - mediate interactions between photoreceptors and bipolar cells main role is lateral inhibition how does the retina increase signal to noise ratio? - CORRECT - lateral inhibiton amacrine cells - CORRECT - contact bipolar and ganglion cells neuromodulatory cells that control the gain of the system, how strongly signals are processed in retina, etc a2 amacrine cells connect rods to bipolar cells
synapses in the ipl ganglion cells - CORRECT - final output neurons of retina, project their axond through the optic nerve to various places in brain on and off center types types of c-opsins - CORRECT - 1. LW opsin- includes human M and L
- SW opsin- includes human S
- rhodopsin- rods opsins in cones - CORRECT - 1. Human M- found in green cones
- human L- found in red cones
- Human S- found in blue cones my green lemur rod sue's bike
