(LE 3) Sensory Physiology Flashcards
What is the function of a receptor?
Responds to specific stimulus it’s made for
Define transduction
environmental info changed into APs (common language of NS)
Define modality
Form of sensory info (e.g. sound, light, pressure)
Define Generator potential
Sensory receptor equivalent of EPSPs and are activate by stimuli instead of neurotransmitters
What is a receptive field? What is the significance of their size?
Area of skin monitored by sensory neurons. Smaller receptive fields = higher tactile acuity (high density of receptors)
What are mechanoreceptors?
respond to deformation of their cell membrane
What are special sense receptors?
part of a sensory organ
- sense hearing, sight, equilibrium, etc.
What are cutaneous receptors?
near epithelial surface
- respond to touch, pressure, temperature, or pain
What are tonic receptors?
respond at constant rate as long as stimulus is applied (e.g. pain)
- slow-adapting
What are phasic receptors?
Respond at high frequency intially, but quickly reduce frequency to constant stimulation (adaptation) e.g. smell, touch
How does the frequency of the action potential relate to the intensity of the stimuli?
Generator potential proportional to stimulus activity. After threshold is reached, AP frequency is proportional to amplitude of generator potential
What structures are found in the inner ear?
Vestibular apparatus (otolith organs (urticle and saccule) and semicircular canals) and cochlea
What is the function of the semicircular canals?
oriented in 3 planes; give sense of angular acceleration via hair cells in crista ampullaris at base
What is the function of the vestibule?
Sense linear acceleration via sterocillia in
Urticle: sense horizontal acceleration
Saccule: sense vertical acceleration
What is the function of the cochlea?
Converts sound vibrations into nerve signals that are interpreted by the brain as sound
What is the function of the oval window?
Where sound vibrations enter the cochlea
What is the round window?
Where sound vibrations exit the cochlea into the eustachian tube
What is the function of the tympanic membrane?
vibrates in response to sound waves and transmits these vibrations to the ossicles in the middle ear
Where are the receptors for hearing located?
hair cells in the tectorial membrane
Describe the hearing pathway
External auditory meatus -> Tympanic membrane -> auditory ossicles (malleus, incus, stapes) -> oval window -> scala vestibuli -> tectorial membrane -> Stereocilia -> vestibulocochlear nerve
How is pitch determined? Volume?
Frequency of soundwaves; amplitude of soundwaves
What is tonotopic? How is it related to tone?
Neurons in different regions of cochlea stimulate corresponding areas of auditory cortex representing different tones
What is the pigmented layer?
absorbs excess light
What is the neural layer?
AKA retina; contains rods, cones, and special sense neurons
