Module 4.4 - Touch and the Chemical Senses Flashcards
what are the 6 independent senses of touch?
1) pressure
2) warmth and cold
3) pain
4) vibration
5) movement
6) stretch of skin
what do the sensations of touch depend on?
these sensations depend on several different kinds of receptors
what are the 4 steps “from touch to brain”
1) A skin (or internal organ) receptor is stimulated
2) A signal travels up the spinal cord
3) Initial signals are processed by the thalamus
4) Signals are sent to the somatosensory cortex
true or false: sensitivity to touch varies across different regions of the body
true
more sensitive areas are allotted more _____ in the parietal cortex
more tissue
true or false: touch is not sensitive to change
FALSE: touch is very sensitive to change
Haptics
the active, exploratory aspect of touch sensation and perception
Kinesthesis
the sense of bodily motion and position
where are receptors for kinesthesis?
muscles, joints and tendons
what is kinesthesis involved in?
balance, movement and handling objects
nociception
the activity of nerve pathways that respond to uncomfortable stimulation
where are nociceptors found?
in our skin, teeth, corneas, and internal organs
what are the 2 types of nerve fibers that transmit pain messages?
1) Fast Fibers
2) Slow Fibers
Fast Fibers
register sharp immediate pain (e.g., the pain of cutting yourself)
Slow Fibers
register chronic, dull pain (e.g., the lingering feelings after stubbing your toe)
Gate-Control Theory
our experience of pain is an interaction between nerves that transmit pain messages and those that inhibit these messages
where does the interaction between nerves that transmit pain messages and those that inhibit these messages occur?
occurs in the spinal cord
_____ nerve fibers conduct pain messages
small nerve fibers conduct pain messages
_____ nerve fibers conduct other sensory signals (e.g., rubbing)
large nerve fibers conduct other sensory signals
what is the result of stimulation of the small pain fibers?
results in pain
what is the result of the large fibers?
inhibit pain signals
true or false: pain involves physical perception (somatosensory cortex) and an emotional response (anterior cingulate cortex)
True
phantom limb sensations
some amputees report pain and other sensations (itching, muscle contractions) coming from the absent limb
what does amputation do to stimulation of the region of the somatosensory cortex associated with that limb?
amputation reduces stimulation
amputation makes the cells become ________
hypersensitive
mirror box therapy
a treatment used to trick the brain into reducing phantom limb sensations
true or false: taste is not an essential sensation
FALSE: taste was essential for our species survival
what are 2 reasons that make taste essential to our survival?
1) it (usually) leads us to prefer nutrient-rich foods
2) we avoided bad tasting foods (potential toxins)
gustatory system
a sensory system involved in the sensation and perception of taste
what is the main sensory organ of the gustatory system?
the tongue
how many taste buds are on the tongue?
~9000 taste buds
true or false: most neurons are sensitive to a particular type of taste
True
what are the 5 primary tastes?
salty, sweet, bitter, sour, and umami
the bumps on the tongue are called?
papillae
the papillae are lined with?
taste buds
what are found within the taste buds…how many on each taste bud?
there are 15-50 taste receptors per taste bud
how many taste buds does a non taster have?
<15
how many taste buds does a normal taster have?
15-35
how many taste buds does a super taster have?
> 35
population coding
perception of a flavour will involve assessment of the firing patterns of many input channels, not one specific channel
the taste receptors send the signal through the thalamus and on to the ________ in the insula
gustatory cortex
olfactory system
a sensory system involved in smell - the detection of airborne particles with specialized receptors located in the nose
olfactory epithelium
a thin layer of cells that are lined by sensory receptors called cilia, which contain specialized proteins that bind with the airborne molecules that enter the nasal cavity
humans have ~_____ different odour receptors
1000
the patterns of firing allow us to detect ~_______ different odours
10,000
olfactory bulb
a structure on the bottom surface of the frontal lobes that serves as the brains central region for processing smell
multimodal integration
the ability to combine sensation from different modalities such as vision and hearing into a single integrated perception
synaesthesia
a condition involving blended multimodal associations (e.g., chicken that tastes ‘pointy’)
