chapter 5 Flashcards
perception vs sensation
perception is the interpretation of sensation
-sensation: light hitting the retina
-perception: seeing a star in the sky
how are receptor cells limited?
they are limited in the range of stimuli they respond to
- they do not become active until the stimulus exceeds a minimum intensity level
what is vision limited to?
wavelengths in the range of 400-700
adaptation
neurons continue to fire as long as the stimulus continues, but their rate of firing slows down
- the longer the stimulus, the less frequent the action potentials are
acuity depends on what two factors?
- design of the stimulus collection system
- cortical representation
acuity
how accurate your vision is (like shooting an arrow, your fovea is in the middle)
which sense does not synapse within the thalamus?
olfaction
Pathway of olfaction
odorants ->glomeruli (synapse) -> olfactory nerve -> pyriform cortex - > orbitofrontal cortex - >primary olfactory cortex
olfactory epithelium
mucous membrane of the roof of the nasal cavity, where odor receptors are embedded
is smell ipsilateral or contralateral?
Smell sensed through the right nostril is mainly processed on the right side of the brain, but the smell is overall received by both sides
tears modulate social and sexual interactions with others by:
decreasing sexual arousal, decreasing physiological arousal, decreasing testosterone level, brain activity (?)
taste receptor cells are in…
the taste pores, which are in the taste buds, which are on the papillae (bumps on the tongue)
five types of taste
salt, sour, bitter ( the most receptors), sweet, umami
neural pathway of gustation
tastant -> CN7 (facial nerve) -> gustatory nucleus (which is the solitary tract in the nucleus)-> VPM (ventral posterior medial nucleus (thalamus)) -> primary gustatory cortex (which is connected to the orbitofrontal cortex
when does sensory transduction begin?
when a tastant (food molecule) stimulates a taste receptor cell and causes it to depolarize
what is the essential role of the basic tastes?
to activate the appropriate behavioral; actions: consume or reject
somatosensory perception
perception of all mechanical stimuli; indicate position of our limbs/head, and our senses of temp, pressure, touch, and pain
Meissner’s corpuscles
general touch (medium)
nociceptors
pain
proprioceptors
tell you where the position of your body is
Merkel’s cells
light touch (outer layer of skin)
Pacinian corpuscles
deep touch (deep in skin)
Ruffini corpuscles
temperature
Different between myelinated and nonmyelinated afferent pain neurons
myelinated is sharp, quick pain, and unmyelinated is dull long pain (like the pain after a burn)
neural pathway of somatosensation
touch receptors -> spinal cord -> medulla (first synapse) -> midbrain/thalamus -> primary somatosensory cortex (S1)
sensory homunculus
the somatotopic representation of the body which is in S1
somatotopic maps
show variation with species, certain body parts are sized based on their usage
- ie spider monkey have large tails and rats have long whiskers
secondary somatosensory cortex S2
build more complex representations
- may code more info about object texture and size
- builds up an integrated representation of the somatosensory info
how is audition organized
tonotopically
neural pathway of audition
auditory nerve -> cochlear nerve -> superior olivary complex -> inferior colliculus -> medial geniculate nucleus of the thalamus -> primary auditory cortex
rods and cones (photoreceptors)
rods- black and white and dim light (in the periphery)
cones - color and bright light (fovea)
distribution of photoreceptors on retina
fovea - cones
peripheral retina - both cones and rods
periphery - rods (few cones) red green and blue cones
rods and cones are connected to…
bipolar cells which synapse with ganglion cells (outer layer of retina)
optic nerve
transmits info from ganglion cells to the central nervous system
neural pathway of vision
retina - > optic nerve -> crosses over at optic chiasm -> lateral geniculate of thalamus -> primary visual cortex
how is vision organized
retinotopic maps
receptive field
part of the visual field that excites or inhibits a cell in the visual system of the brain
structures in the outter ear
pinna and auditory canal
structures in the middle ear
ossicles (malleus, stapes, incus), and oval window
structures in inner ear
cochlea/hair cells and auditory nerve
