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19 Cards in this Set
- Front
- Back
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Sensory Transduction
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Incoming stimuli (chemical or physical stimuli from an animal’s body or the external environment) are converted into neural signals
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Perception
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Awareness of sensations
Not all sensations are consciously perceived by an organism |
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Sensory Receptor
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Recognizes stimulus and initiates signal transduction by creating graded potentials in itself or adjacent cell
When the response is strong enough and action potential is sent to the CNS |
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Receptor Types
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Mechanoreceptors – transduce mechanical energy
Thermoreceptors – respond to cold and heat Nociceptors, or pain receptors – respond to extreme heat, cold, and pressure, as well as to certain molecules such as acids Electromagnetic receptors – detect radiation within a wide range of the electromagnetic spectrum Photoreceptors – respond to visible light energy Chemoreceptors – respond to specific chemicals |
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Mechanoreception
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Physically touching or deforming a mechanoreceptor cell opens ion channels in the plasma membrane
Some mechanoreceptors are neurons Others are specialized epithelial cells |
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Stretch Receptors
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Commonly found in the walls of organs that can be distended
Stretching deforms them and they depolarize Send action potentials to the brain Stretching in stomach is interpreted as fullness |
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Hair Cells
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Specialized epithelial cells
Deformable stereocilia resemble hairs Ion channels open or close when cilia bend Changes membrane potential Found in the ear and equilibrium organs, body surface of fish and some amphibians |
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Lateral Line System
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Hair cells that detect changes in water currents
Stereocilia of hair cells protrude into cupula within lateral line system When cupula moves, cilia bend, and neurotransmitter released |
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Amphibians
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Adaptations to hearing on land and in water
No external ears Tympanic membrane located on outer surface Unusually wide Eustachian tubes Sound can pass through Eustachian tubes or from lungs to Eustachian tubes |
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Proprioception
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Ability to sense the position, orientation, and movement of the body
Many aquatic invertebrates have statocysts to send positional information Small round structures made of hair cells and statoliths (dense object) |
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Thermoreception
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Respond to either hot or cold temperatures by activating or inhibiting enzymes within their plasma membranes, altering membrane channels
2 types of thermoreceptors – hot and cold Both free neuronal endings Thermoreceptors in the brain detect core body temperature Activation of receptors can cause physiological and/or behavioral adjustments to maintain body temperatur |
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Nociceptors
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Free neuronal endings in skin and internal organs
Respond to tissue damage or to stimuli about to cause tissue damage Can respond to external stimuli like extreme temperatures and internal stimuli like molecules released from injured cells |
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Electromagnetic Sensing
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Detect radiation within a wide range of the electromagnetic spectrum
Includes wavelengths that correspond to visible light, ultraviolet light, and infrared light, as well as electrical and magnetic stimuli Fish detect electrical signals from other fish Platypus bill detects electrical currents from prey Homing pigeons use magnetite to navigate home Pit vipers sense heat from prey as infrared radiation |
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Photoreception
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Photoreceptors detect photons of light arriving from the sun or other light source, or reflecting off an object
Photon – fundamental unit of electromagnetic radiation with the properties of both a particle and a wave |
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Rods
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Sensitive to low intensity light
Do not discriminate colors Used mostly at night |
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Cones
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Require more light for stimulation
Detect color Fewer cones than rods in human retina |
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Pigments
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2 compounds bonded together
Retinal – vitamin A derivative that absorbs light energy Opsin – several types G-protein-coupled receptors that change membrane permeability to ions Rhodopsin in rods Cone pigments or photopsins in cones |
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Chemoreception
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Olfaction – sense of smell
Gustation – sense of taste Chemicals bind to chemoreceptors, which initiate electrical responses in other neurons that pass into the brain Close relationship between taste and smell Distinction meaningless for aquatic animals |
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Insects
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Insects
Highly dependent on odor and taste for finding food and mates Chemoreceptors located on sensory hairs on proboscis, legs, feet and antennae Certain moths have males with elaborate antennae to sense pheromones released by female |
