Sensory Systems Flashcards
Sensation
Allows organisms to react to stimuli
What are the four stages of sensation?
- Reception-detection of stimulus and receptors receive signal
- Transduction-neurons fire action potentials and signals are sent via transduction cascade
- Transmission-signal is sent to the brain to be processed
- Perception-brain processes signal
What are the 5 classes of sensory receptors?
Mechanoreceptors, chemoreceptors, electromagnetic receptors, thermo receptors, and nociceptors
Mechanoreceptors
Respond to touch, vibration, audition, stretch, pressure; Ex: whiskers, ears
Chemoreceptors
Respond to osmolarity, smell, taste; Ex: tongue
Electromagnetic receptors
Respond to electrical current, light, magnetic fields; Ex: eye (senses light waves)
Thermo receptors
Respond to hot and cold; Ex: snakes have infrared vision
Nociceptors
Respond to pain
Perception
Neural representation of the world
Olfaction
Oldest sense; sense of smell; chemo sense; present in bacteria; long range detection of fluid borne molecules
What are examples of parts of the body that detect smell?
Nares (nostrils), antennae, tentacles, olfactory epithelium, echinoderms also can sense smell
What is the pathway of smell?
- Reception: Olfactory receptor cells express olfactory receptors that bind to odorants and each olfactory cell expresses only one type of receptor.
- Transduction: Odorants bind to ORs to trigger action potentials in olfactory receptor cells.
- Transmission: Odor intensity is encoded in how many olfactory cells were stimulated; sent to olfactory processing part of the brain.
- Perception: combination of olfactory cells being stimulated=identification of that specific odor
Odorants
Odors are mixture of chemicals
Vision
Has evolved many times; sight; an electromagnetic sense
Example of eyes with no lenses.
Eyespots on flat worms, eyecup, and pinhole eyes
Examples of camera lens eyes.
Compound eyes, simple eyes on spiders, chambered eyes
Photoreceptors
Contain opsins
Opsins
In photoreceptors and are proteins that contains retinal
Retinal
Photosensitive pigments that respond to light
What happens to the cis-retinal when a photo hits it?
The kink is removed and it becomes a trans-retinal and is ejected out of the opsin; this is detection of light
Rods
Photo sensory cell in the retina that detects around 500 nm (between blue and green); not good w/ red; is there to detect light
Cones
Photo sensory cells in the retina that detects blue, green, and red; sees specific wavelengths
Are there more rods or are there more cones?
There are more rods than cones
What is the pathway of vision?
Light travels through the cornea, pupil, lens and reaches the retina.
- Photoreceptor cells (rods and cones) receive the light.
- Transduction: the signal travels from rods and cones to other cells.
- Transmission: signal reaches the optic nerve where it will be sent to the brain for processing.
- Perception: it reaches the occipital lobe where it processes vision.
Left and right visual fields are processed separately? T or F?
T
What does the loss of cones result in?
Color blindness
The color purple
A non spectral color (not on the chart)
What can animals w/ 4 cones perceive?
5 non spectral colors
