sensing the wolrd I Flashcards
what is sensation?
the capacity to detect physical or chemical stimuli using sensory organs and afferent nerves
what is perception?
conscious experience and interpretation of sensory information by the CNS
what is a stimulus?
a thing or event that evokes a functional reaction in an organ or tissue
what types of stimuli exist?
Physical (light, sound, heat) and chemical (taste, smell, pheromones)
what is transduction?
The process by which sensory organs convert stimuli into neuronal activity.
what is the function of human sensory systems?
To capture and transduce stimuli into neural signals for the brain.
how do electric fish use electrolocaiton?
They generate and detect small electric fields to “see” objects and communicate.
what is special about the cockeyed squid’s vision?
One large eye looks up for predators; a small eye looks down for prey.
what are sensory receptors?
Specialized cells that convert external stimuli into neural activity.
Name four types of sensory receptors.
Photoreceptors (light), mechanoreceptors (movement), chemoreceptors (chemicals), nociceptors (pain).
what is receptive field?
specific part or quality of the world detected by a sensory receptor
are receptors distributed evenly?
No, distribution is non-homogeneous, and receptors have detection thresholds.
how does sensory information travel to the brain?
through neural relays, modifying the information at each step
is sensation the same as perception?
No, perception involves context, emotion, and memory beyond raw sensation.
what are the four key points about sensing?
1 organ = 1 modality; animals have different abilities; receptors transduce stimuli; neural pathways deliver info to the brain.
how developed is human vision?
Highly developed for day colour vision, and sensitive enough to detect light from distant galaxies.
which cortex is the largest sensory cortex?
visual cortex
What part of the electromagnetic spectrum is visible light?
the section that the human eye can detect
how does light reach the eye?
directly from sources or after reflecting off objects
What controls the amount of light entering the eye?
iris (adjusts the pupil)
what structures focus light onto the retina?
cornea and lens
what is the function of the optic disc?
passageway for blood vessels and the optic nerve
what is the fovea specialised for?
Acute, detailed colour vision during daylight (packed with cones).
what is the periphery specialised for?
Sensing very dim light (rich in rods)
