sensory systems

Question 1

what are the general principles of sensory systems?

Answer 1

• 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

Question 2

what is sensory transduction?

Answer 2

sensoty stimulus to neural impulses

Question 3

what are sensory pathways?

Answer 3

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

Question 4

what is sensory coding?

Answer 4

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

Question 5

what is rate coding?

Answer 5

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

Question 6

what is receptive field?

Answer 6

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

Question 7

what is topographic organisation?

Answer 7

• they are maps in the brain

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

Question 8

what structural features do eyes have?

Answer 8

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

Question 9

what is involved in phototransduction?

Answer 9

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

Question 10

what are the stages in phototransduction?

Answer 10

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

Question 11

what is the visual pathway from retinal to visual cortex?

Answer 11

• 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

Question 12

what is the hearing range?

Answer 12

what we can hear

Question 13

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

Answer 13

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

Question 14

what are average intensities of sound in:

• a very calm room
• a normal conversation
• hearing damage
• jet engine
• threshold of pain

Answer 14

• 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

Question 15

what is amplitude in terms of the auditory system?

Answer 15

strangth of the wavelength

Question 16

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

Answer 16

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
-

Question 17

what happens to the ear drum at different sounds?

Answer 17

• 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

Question 18

what happens after auditory transduction in the cochlea?

Answer 18

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

Question 19

what is the auditory receptive field?

Answer 19

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

Question 20

what is the tonotopic map?

Answer 20

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

Question 21

what is the sensory organ for touch?

Answer 21

skin

Question 22

what stomasensory receptors are involved wirth the skin?

Answer 22

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

Question 23

what are the 2 afferent fibres for pain reception?

Answer 23

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

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

Question 24

what is the spinothalamic tract?

and what does it consist of?

Answer 24

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

Question 25

what are the stages for the 'dorsal column-medial meniscal pathway'

Answer 25

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

Question 26

what is our topographic map called? | what parts of the body are over represented in the map?

Answer 26

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

Question 27

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

Answer 27

olfactorys system for smell | gustatory system for taste

Question 28

where are the olfactory receptor cells?

Answer 28

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

Question 29

what do the olfactory cells do?

Answer 29

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

Question 30

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

Answer 30

the mitral cells send their output to multiple brain regions

Question 30

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

Answer 30

the mitral cells send their output to multiple brain regions

Question 31

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

Answer 31

the 'prirform' cortex which is an olfactory cortex. | the thalamus doesn't directly contribute to olfactory processing

Question 32

what do you know about the tounge?

Answer 32

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

Question 33

what is the gastatory pathway?

Answer 33

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