Week 6: Hearing, Vestibular sense, Somatosensation, Pain, Olfaction. and Taste Flashcards
amplitude
loudness
frequency
pitch, fundamental frequencies
complexity
timbre, fourier analysis
pinna
cartilage around the ear canal
tympanic membrane
ear drum
ossicles
amplify waves
Inner ear
- cochlea
- tectorial membrane
- basilar membrane
- hair cells
- stereocilia
stereocilia
U-shaped structures atop hair cells. as sound waves moves the fluid across the stereocilia, it bends them, triggering responses by the hair cells
frequency theory
the basilar membrane vibrates in synchrony with the sound and causes auditory nerve axons to produce action potentials at the same frequency.
place theory
each area along the basilar membrane has hair cells sensitive to only one specific frequency of sound wave
audiogram
“Hearing test”: how loud (y-axis) does a sound need to be for it to be detected at different pitches (x-axis).
vestibular system
Responsible for our perception of balance:
CN VIII (Vestibular nerve)… Cerebellum/ Brain stem
Vestibular organ
3 semicircular canals (jellylike substance, hair cells)
2 otolith organs (utricle and saccule)
functions of vestibular organs
Position of the body in relation to gravity
Changes in the direction and speed of movements of the head.
Moving the head moves fluid (endolymph) within the 3 semicircular canals
In turn, this pushes against hair cells bending the cilia located on top of the hair cells
Bending cilia leads to receptor potentials in the hair cells and action potentials in the cells forming the vestibular nerve
Direction in which the cilia are bent determines whether the hair cell becomes depolarized or hyperpolarized
somatosensory system
Provides bodily sensations such as:
Touch, temperature, pain, position in space, and movement of the joints
-Allows us to distinguish between what the external environment does to us (hot stove=burn) and what we do to it (withdraw hand)
-It has a closer relationship with motor actions than the other senses do
somatosensory receptors
Areas with larger numbers of receptors are more sensitive to stimulation than areas with relatively fewer receptors
Sensitivity to different somatosensory stimuli depends on the kind of receptor that is stimulated
Stimulating these receptors opens the Na+ channels to elicit an action potential
Humans have 2 kinds of skin: hairy skin, glabrous skin (hairless)
nocioception
pain and temperature
hapsis
fine touch and pressure
proprioception
location and movement of the body and body parts
fast adapting receptor
Responds briefly to the beginning and end of a stimulus on body
Proprioceptive & Hapsis
slow adapting receptor
Responds as long as a sensory stimulus is applied to body
Nocioception & Hapsis
dermatone
a body area innervated by a single sensory spinal nerve.
deafferented
Lost afferent input to a structure
endorphins
a group of chemicals that attach to the same brain receptors as morphine
Morphine does not affect large-diameter axons that convey sharp pain, but it does block signals that are slower from dull pain (e.g. post-surgical pain)
emotional pain
Emotional associations of pain (e.g., break-up, being left out)
Activate a path that goes through the reticular formation of the medulla and then to several of the central nuclei of the thalamus, the amygdala, hippocampus, prefrontal cortex, and cingulate cortex
Brain activity in people with hurt feelings (e.g. being excluded from a social activity) tends to be similar (but not identical) to those experiencing physical pain
substance P
-Spinal cord
-Involved in the transmission of pain info
-Neuropeptide
-Released during intense pain
phantom pain
70% of amputees experience phantom pain (pain that is experienced as if it were in the missing limb)
Phantom pain is just as real a sensation as the phantom limb and is a significant problem in post-amputation pain management
The “phantom” originates in the brain
