senses and vision Flashcards
what is transduction
physical to neuronal activity
what is the organ and stimulus for somatosensation?
organ: skin and other tissue
stimulus: pressure, warmth, cold and pain
what is the organ and stimulus for sight?
organ= eyes
stimulus= light
what is the organ and stimulus for hearing?
organ = ears
stimulus = air vibration
what is the organ and stimulus for smell?
organ= nose
stimulus= volatile chemicals
what is the organ and stimulus for taste?
organ= mouth
stimulus= soluble chemicals
electrolocation and communication in electric fish
- Weakly electric fishes produce and detect small current flows around them.
- They use these currents to “see” objects (electrolocation) and communicate with conspecifics (electrocommunication)
what are the 4 types of sensory receptors
- photoreceptors
- mechanoreceptors
- chemoreceptors
- nociceptors
what do photoreceptors do
detect light
* Vision
also send signals to brain → mapping a particular area in the visual field
what do Mechanoreceptors do
detect movemnt
* sound
* texture [touch]
* blood pressure
* muscle stretch
what do chemoreceptors do
detect chemical compounds
* smell
* taste
what do nociceptors do
detect tissue damage
* pain
what is recpetor density
receptor density is not homogeneous
sensation does not equal perception
- Perception is more complex than sensation.
- The context, emotional state or memories can affect how we perceive the same sensory experience. This is exemplified by optical illusions such as the Rubin’s vase or the Muller-Lyer illusion.
humans and colour vision
- Humans possess highly develop day colour vision, but are also capable of detecting light coming from galaxies 2 million light years away from Earth.
- Visual cortex [in back of brain+ quite expansive] extends further than any other sensory cortices.
- Through seeing and perceiving the world around us we assess reality, but also can produce adaptive behaviours.
light as a stimulus
Visible light: section of the electromagnetic spectrum that the human eye can detect.
* Light can enter the eye from a source of light, or after bouncing on an object.
what does the iris do
The iris opens and closes to allow more or less light through the pupil
what does the optic disc do
The optic disc allows vessels going in and out, and the optic nerve to carry visual information to the brain
what do the cornea and the lens do
The cornea and the lens focus the light into the retina, where the image is recreated.
the retina
- The fovea is mainly covered by densely packed cones (acute vision during daylight).
- The periphery is covered by rods, which are more sensitive to light than cones (sense very dim light).
how many types of cones are there in the retina
3
what are the 3 types of light cones
blue, green, red
