chap 5 Flashcards
what is sensation?
the act of using our sensory systems to detect environmental stimuli
what is perception?
the conscious recognition and identification of a sensory stimulus
name 5 types of sensory systems?
olfactory (smell), somatosensory (touch, heat, pain), gustatory (taste), auditory (hearing), visual (sight)
examples of physical stimuli
odourants (airborne chemicals), psi or dmg to the skin, chemicals (typically in food), sound waves, light (photons)
what are sensory receptor cells
specialized cells that convert a specific form of environmental stimuli into neural impulses
sensory transduction
the process of converting a specific form of environmental stimuli into a neural impulse that our brain can read
sensory homunculus?
the somatosensory stirp that senses external stimuli
what is an absolute threshold?
smallest amount of a stimulus that one can detect
what is the difference threshold (just notice difference)?
the minimal difference needed to notice a difference between 2 stimuli
signal detection theory
the response to a signal in every situation depends on an individ’s ability to differentiate between the signal and noise, and on their response criteria
what is sensory adaptation
repeated stimulation of a sensory cell leads to a reduced response
what is bottom up processing?
transduces neural impulses that move successively into more complex brain regions
what is top down processing
perception processes led by cog processes, such as memory or expectations –> using prev knowledge
perceptual set
readiness to interpret a certain stimulus in a certain way (optical illusions)
what are odorants? + their cells?
airborne chemicals that are detected as odours + olfactory receptor neurons (convert signals from odourants to neural impulses.
how do we sense taste?
papilae (bumps on tongue that contain taste buds), taste buds (sensory receptor cells that convert chem signals from food to neural impulses)
what are the 5 taste receptors on the tongue?
sweet, sour, bitter, salt, umami
what sensations also contribute to eating other than smell and taste?
texture –> consistency of food and thus explains why some textures are rejected
what is well developed at birth and why?
smell (newborns have a preference for odor of their mother’s milk), taste is also well developed (preference to sweet and dislike for bitter)
gender diff in taste and smell?
females more sensitive to odours than males, some are more sensitive to bitter substances than others (“super-tasters”)
what is aguesia?
inability to taste
what is anosmia?
inability to detect odours
what is hyposmia?
reduced ability to smell
what is reflex epilepsy
a seizure occurs only after exposure to a specific odour
migraine headaches
specific odours can trigger migraines
what are tactile senses? (5)
pressure, touch, temp, vibration, pain
what are free nerve endings
detect touch, psi, pain and temp -> located near the surface of the skin
what are meissner’s corpuscles
transduce info about sensitive touch -> located in fingertips, lips and palms (hairless skin areas)
what are merkel’s discs?
transduce info about light to moderate psi against the skin-> located near surface of the skin
what are ruffini’s end organs
registers heavy psi and movement of the joints –> located deep in the skin
pacinian corpuscles
respond to vibrations and heavy psi –> deep in the skin
steps to perceiving touch?
- tactile receptors respond to touch and psi and send info to spinal cord
- spinal cord -> thalamus
- thalamus -> somatosensory cortex
- the somatosensory cortex receives the info
what are 2 pathways of pain
fast pathway, slow pathway
what is the fast pathway of pain?
-myelinated path where pain is sharp and localized and felt quicker
what is the slow pathway?
-unmyelinated so pain is often burning and long..
gate control theory of pain
a gate can be closed and prevents pain msgs from being perceived
what is the most common tactile sense disorder?
chronic pain
what relieves chronic pain? (chem, drug, theory)
endorphins and enkephalins are chemicals that have pain-relieving properties, opiates mimic pain relief, gate control theory and touch sensations –> alleviate acute pain