Exam 3 Flashcards

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1
Q

hearing

A
  • we hear the change in pressure in air that surrounds us

- helps us locate objects in space

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2
Q

amplitude

A
  • how loud, measured in decibels (dB)

- the height of the wave

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3
Q

frequency

A
  • the pitch
  • wave cycles per second
  • more cycles means higher frequency
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4
Q

outer ear

A

functions to funnel sound into middle ear

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5
Q

middle ear

A
  • concentrates energy/sound from a large area to a small surface area
  • sound is amplified when ear drum sends info to malleus –> incus –> stapes
  • stapes sends mechanical energy to oval window
  • concentration of energy from ear drum to oval window goes from a high surface area to low surface area (sounds amplification)
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6
Q

tensor tympani and stapedius muscles

A

function to dampen the vibration of ossicles in order to prevent damage to ear

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7
Q

inner ear

A

made up of cochlea

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8
Q

organ of corti

A
  • has 2 sets of sensory cells:
    • inner hair cells
    • outer hair cells
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9
Q

stereocilia

A

protrudes from each hair cell

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10
Q

tip links

A

thin fibers that run across each hair cell’s stereocilia

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11
Q

auditory info sent to brain

A
  • vibration makes stereocilia sway, causing K and Ca ion channels to open
  • high concentration of K+ outside cell and low concentration inside cell
  • K+ enters cell when sound waves come into ear
  • K+ depolarizes hair cell, causing voltage gated Ca2+ channels to open at base of cell
  • Ca2+ entry causes release of glutamate or acetylcholine to ganglion neurons
  • glutamate or acetylcholine activate ganglion neurons to send sound signals to brain
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12
Q

hair cell depolarization

A

hair cells are depolarized by K+

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13
Q

basilar membrane

A
  • sound vibrations cause basilar membrane to oscillate
  • different parts respond to different frequencies:
    • high frequency –> displaces narrow base of basilar membrane
    • low frequency –> displaces wider apex
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14
Q

inner hair cell releases…

A

glutamate

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15
Q

outer hair cell releases…

A

ACh

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16
Q

function of inner hair cells

A

send auditory information to brain

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17
Q

function of outer hair cells

A

amplify sound

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18
Q

cortical tonotopy of auditory cortex

A
  • higher frequency in posterior auditory cortex

- lower frequency in anterior auditory cortex

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19
Q

encoding frequency properties of a sound

A
  • place coding or tonotopic representation
  • temporal pattern of firing of cells:
    • higher firing rates for higher frequency
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20
Q

encoding loudness of a sound

A

movement of basilar membrane

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21
Q

sound location detection

A
  • binaural cues signal sound location:
    • intensity differences: different in loudness at the 2 ears
    • latency differences between the 2 ears in the “time of arrival” of sounds
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22
Q

auditory pathways of human brain

A

cochlear nucleus –> switches side of brain –> superior ovilary nucleus –> inferior colliculus –> medial geniculate nucleus –> auditory cortex

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23
Q

retina

A
  • images a mirrored upside down on retina
  • contains 3 primary layers: ganglion cell layer, bipolar cell layer, photoreceptor cell layer
  • contains rods and cones
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24
Q

activation profile of visual system

A
  • light bounces off image end enters eye
  • light hits retina at back of eye
  • visual info from retina travels down optic tract
  • optic tract sends visual info to lateral geniculate nucleus (LGN) of the thalamus
  • thalamus separates visual info and sends it to primary visual cortex (V1)
  • V1 further breaks down components of image
  • V1 is where visual perception occurs
  • V1 sends info to dorsal and ventral pathways
25
Q

the colors we see…

A

are wavelengths bouncing off that object

26
Q

fovea

A
  • where vision is sharpest and where one focuses on objects

- highest density of cones

27
Q

process of light entering eye

A
  • cornea and lens focus light entering eye onto retina
  • refraction is done by cornea and lens
  • bending of light focuses image onto retina
  • ciliary muscles in eye adjust focus by changing shape of lens
  • light hitting retina activates photoreceptors
  • vision is sharpest at fovea
28
Q

refraction

A

bending of light

29
Q

optic disc

A

where blood vessels enter and leave eye

30
Q

blind spot

A

due to lack of photoreceptors in optic disc

31
Q

information transfer of the retina

A
  • photoreceptors (rods and cones) respond to light
  • photoreceptors do not fire action potentials, but send a signal (glutamate) to activate the bipolar cells
  • the bipolar cells don’t fire action potentials but release glutamate to activate the ganglion cells
  • ganglion cells are the first sight where action potentials occur
  • the axons of the ganglion cells form the optic tract
32
Q

bipolar cells

A

receive input from photoreceptors and synapse on ganglion cells, whose axons form the optic nerve

33
Q

horizontal cells

A

are in the retina and contact photoreceptors and bipolar cells

34
Q

amacrine cells

A

contact bipolar and ganglion cells

35
Q

rhodopsin

A
  • opsin + retinal = rhodopsin
  • it is a GPCR
  • when light activates retinal to change shape, the g protein (transducin) activates phosphodiesterase (PDE)
  • PDE turns cGMP into GMP
  • cGMP activates voltage gated Na+ channels
  • light hyperpolarizes the rods
  • in the dark rods are depolarized
36
Q

3 types of cones

A

there are cones that respond to either blue, green, or red light and are called S, M, L (for short, medium, and long wavelength light)

37
Q

optic tract

A
  • groups left visual fields into the right visual cortex

- groups right visual fields into the left visual cortex

38
Q

optic chiasm

A
  • ganglion cell axons form the optic nerve and cross at the optic chiasm
  • after passing the optic chiasm, the axons are called the optic tract
  • most axons synapse on cells in the lateral geniculate nucleus (LGN) of the thalamus
39
Q

LGN

A
  • information is sent to LGN from optic tract
  • LGN is the first structure in the brain where visual information is processed
  • LGN contains layers that separate visual movement
40
Q

where pathway

A

dorsal
V1 –> V2 –> area MT –> posterior parietal lobe
vision for movement, location

41
Q

what pathway

A

ventral
V1 –> V2 –> V4 –> inferior temporal cortex
vision for recognition (objects, faces)

42
Q

where and what pathways come together in…

A
  • hippocampus
  • why memories are highly visual (visual dreams)
  • both pathways are important for autobiographical learning and memory
43
Q

cochlear duct

A

contains tectorial membrane, organ of corti, and basilar membrane

44
Q

primary regions of CNS that control movement

A
  • ACh: initiates muscle contraction
  • muscles: moves your skeleton
  • spinal cord: sends and receives commands and the reflex
  • basal ganglia: motor learning
  • motor cortices: motor command
45
Q

motor system

A
  • brain can initiate movement and receives information about movement
  • simplest form of movement is the reflex (does not require a brain)
  • complex movements are obvious
  • many pathologies affect motor system (parkinson’s and huntington’s)
46
Q

human motor cortical areas

A
  • premotor cortex
  • supplementary motor area
  • primary motor cortex
47
Q

primary motor cortex

A
  • primary motor cortex maps the body

- homunculus

48
Q

homunculus

A

represents the area of the motor strip relating to its body part

49
Q

movements are controlled at several nervous system levels

A
  • in a reaching task, muscle cells change firing rate according to the direction of the movement
  • each cell has one direction that elicits highest activity
  • an average of the activity can predict the direction of the reach
50
Q

premotor cortex selects motor commands

A
  • encodes the intention to perform a particular movement; thus, they are involved in the selection of movements based on external events
  • your brain will have already initiated movement before you are aware of the movement you will make
  • you perceive that the choice was yours, but the choice occurred prior to perception
51
Q

motor cortices receive and send…

A

axons/information to the basal ganglia
example of riding a bike:
- basal ganglia receives commands from motor cortex
- basal ganglia permits motor commands to initiate
- cortex may not know exactly what commands to send (but has general idea)
- commands are not accurate before learning
- during motor learning/procedural learning basal ganglia “fine tunes” motor commands

52
Q

basal ganglia

A

motor learning AKA procedural learning

53
Q

basal ganglia circuitry

A

substantia nigra and ventral tegmental area regulate dopamine production

54
Q

additional functions of the basal ganglia

A
  • habitual learning
  • drug addiction
  • procedural learning
  • parkinson’s disease
  • huntington’s disease
  • eye movement
  • motor planning
55
Q

spinal cord components

A

cervical
thoracic
lumbar
sacral

56
Q

spinal input and output

A
  • dorsal root: carries sensory information from the body to the spinal cord
  • ventral root: carries motor information from the spinal cord to the muscles
57
Q

spine synapse to…

A

muscles at neuromuscular junction

58
Q

ACh initiates muscle contraction

A
  • motoneurons are nerve cells in the spinal cord that send their axons in innervate muscles
  • action potentials travel down the motoneuron, which branches into many terminals near its target
  • neurotransmitter ACh is released –> causes Ca2+ to be released –> causes myosin heads to move towards actin –> muscle contraction