Other senses 2.4 [HY] Flashcards
Does smell go through thalamus?
No, the only sense that does not pass through the thalamus, but rather travels—unfiltered—into higher-order brain centers
Pheromones
chemicals secreted by one animal, and which, once
bonded with chemoreceptors, compel or urge another animal to behave in a specific way
Smell Pathway
Nasal Passages -> Olfactory Nerves (receptors) -> Olfactory bulb -> Olfactory Tract -> Higher brain regions
Taste Pathway
Taste Buds -> Brainstem -> Taste Center -> Higher Brain Regions
Meissner corpuscles
respond to light touch
Ruffini endings
respond to stretch
Free nerve endings
respond to pain and temperature
Pacinian corpuscles
respond to deep pressure and vibration
How do pain and temperature, pressure and vibration travel through spinal cord?
Pain and temperature ttravel the same side
and
Pressure and vibration travel same side
Touch Pathway
Receptors -> CNS -> Somatosensory cortex
Two-Point Threshold
- minimum distance
necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli. - depends on the density of nerves in the particular area of skin being tested.
Physiological Zero
- normal temperature of the skin (between 86° and 97°F)
- object feels “cold” because it is under physiological zero; an object feels “warm” because it is above physiological zero.
Gate Theory of Pain
- a special “gating” mechanism can turn pain signals on or off, affecting whether or not we perceive pain.
- spinal cord can preferentially forward the signals from other touch modalities (pressure, temperature) to the brain, thus reducing the sensation of pain.
Where are proprioceptors found?
found mostly in muscle and joints
