sensory systems Flashcards

1
Q

what are the general principles of sensory systems?

A
  • each sensory organ has specialised sensory receptors
  • each sensory system has a sensory pathway from receptors to the brain
    across the sensoty system there are specialised sensoty receptor cells depending on the sensoty system
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2
Q

what is sensory transduction?

A

sensoty stimulus to neural impulses

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3
Q

what are sensory pathways?

A

there are multiple neurons that relay sensory signals to the sensoty cortex

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4
Q

what is sensory coding?

A

this is how neurons encode sensory signals by their electrical activity, which is their action potential

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5
Q

what is rate coding?

A

this means a certian feature of sensory stimulus (such as stimulus intensities) can be encoded by the rate or frequency of action potential

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6
Q

what is receptive field?

A

different neurons react in different ways to differentiate wavelengths of light
other sensory neurons also have receptive fields

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7
Q

what is topographic organisation?

A
  • they are maps in the brain

as an entire collection of sensory neurons, you can find a ‘topographic organization’ in each sensoty area

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8
Q

what structural features do eyes have?

A

the retina- the most important structure of the eye, this contains photoreceptor cells
photoreceptor cells - rods (dim light) and cones (bright light and colour)

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9
Q

what is involved in phototransduction?

A
  • ## rhodopsin (GPCRs and diferent types of rhodopsins detect different response spectra)
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10
Q

what are the stages in phototransduction?

A

photoreception triggers intracellular signalling to hyperpolarise photoreceptor cells

  • after initial photoreceptor cells, neutral cells propagate throughout the retinal layers
  • retinal ganglion cells are output cells which send signals to the second-order visual areas called the lateral geniculate nucleus in the thalamus
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11
Q

what is the visual pathway from retinal to visual cortex?

A
  • retina
  • optic nerve
  • optic chiasm
  • lateral geniculate body
  • primary visual cortex
  • left hand of the scene > processed by the right hemisphere of the brain
  • right hand of the scene > processed by the left hand side of the brain
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12
Q

what is the hearing range?

A

what we can hear

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13
Q

what frequency of sound can dogs, humans and mice hear?

A

humans- 20Hz- 20,000Hz
dogs - 40Hz - 60,000Hz
mice- 1000Mz- 70,000Hz

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14
Q

what are average intensities of sound in:

  • a very calm room
  • a normal conversation
  • hearing damage
  • jet engine
  • threshold of pain
A
  • Very calm room: 20-30 dB SPL
  • Normal conversation: 40-60 dB SPL
  • Hearing damage: 85 dB SPL
  • Jet engine: 110-140 dB SPL
  • Threshold of pain: 130-140 dB SPL
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15
Q

what is amplitude in terms of the auditory system?

A

strangth of the wavelength

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16
Q

what is the sense of hearing acomplished by? and what are steps involved in it?

A

auditory transduction
- the ear concerts sound waves in the air into electrical impulses which can then be interpreted by the brain
- as sound eneters the ear, it travels down the ear canal and to the ear drum
-

17
Q

what happens to the ear drum at different sounds?

A
  • a lower pitch produces a slower vibration
  • sounds of a higher pitch produces a faster vibration
  • sounds of a lower volume produces a less dramatic vibration
    the ear drum is cone shaped and articulates with a chain of bones known as the auditory ossicles, the malleis, the incus and the stapeduis
18
Q

what happens after auditory transduction in the cochlea?

A
the auditory pathway 
the steps are:
- cochlea
- cochlear nucleus 
- superior olivary complex
- inferior colliculus 
- medial genticulate body
- auditory cortex
19
Q

what is the auditory receptive field?

A

characteristic frequency which can emit sound-evoked responses at the minimum intensity

20
Q

what is the tonotopic map?

A

toporaphic organisation in the auditory system is called ‘tonotopic map’ or ‘tonotopic organisation’
tonotopic organisation can be found not just in the cochlea, but also in the auditory cortex

21
Q

what is the sensory organ for touch?

A

skin

22
Q

what stomasensory receptors are involved wirth the skin?

A
  • mechanoreceptors (the reaceptors for touch)
  • thermoreceptors (the receptors for temperature)
  • nociceptors (the receptors for pain)
23
Q

what are the 2 afferent fibres for pain reception?

A

A-delta is myelinated, meaing it can send signals quickly

C-fibre is un-myelinated meaning that it sends signals slowly

24
Q

what is the spinothalamic tract?

and what does it consist of?

A

its the pathway for nociception and thermoreception
it consists of:
1. dorsal root ganglia
2. spinal cord
3. ventral posterior nucleus of the thalamas
4. primary stomasensory cortex

25
Q

what are the stages for the ‘dorsal column-medial meniscal pathway’

A
  1. dorsal root ganglia
  2. dorsal column nuclei
  3. ventral posterior neucleus (thalamas)
  4. primary stomasensory cortex
26
Q

what is our topographic map called?

what parts of the body are over represented in the map?

A

stomatic map

the hands and face - this means that they are much more sensitive

27
Q

what are the names of the sensory systems for smell and taste?

A

olfactorys system for smell

gustatory system for taste

28
Q

where are the olfactory receptor cells?

A

theyre inside the nose, there is the nasal epithelium which contains olfactory receptor cells

29
Q

what do the olfactory cells do?

A

they provide signals to the olfactory bulb, where mitral cells are output cells which send signals to the brain regions

30
Q

why is the olfactory pathway unique compared to other sensoty pathways?

A

the mitral cells send their output to multiple brain regions

30
Q

why is the olfactory pathway unique compared to other sensoty pathways?

A

the mitral cells send their output to multiple brain regions

31
Q

what is the main area of the brain mitral cell outputs are sent?

A

the ‘prirform’ cortex which is an olfactory cortex.

the thalamus doesn’t directly contribute to olfactory processing

32
Q

what do you know about the tounge?

A

thre are 5 modalities in taste reception
thier receptors are distributed across the tongue in a similar fashion
the tastebud is the structure of taste reception and it contains receptor cells with microvilli

33
Q

what is the gastatory pathway?

A
  1. taste buds
  2. nucleus of the solitary tract
  3. ventroposterior medial nucleus
  4. insular cotrex