Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

4. BIOL257 > Sensory physiology: principles > Flashcards

Sensory physiology: principles Flashcards

1
Q

efferent nerves/ descending pathways: define

A
  • somatic motor neurons/ autonomic moto neurons

- relay signals form CNS towards an effector (organ, muscle, gland)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

afferent nerves/ ascending pathways: define

A
  • sensory neurons

- relay signals from sensory receptors in PNS towards the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

general visceral afferents:

A
  • provide input to brain about viscera

- processed mostly subconsciously for homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

special visceral afferents:

A
  • nerves that develop in association w GIT and carry info from ‘special senses’ of smell and taste via CN I (olfactory), VII (facial), IX (glossopharyngeal), V (trigeminal), X (Vagus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

general somatic afferents:

A
  • transmit sensation arising from body surface (touch, pressure)
  • proprioceptive info from mm, joints, skin, inner ear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

special somatic afferents:

A
  • nerves carry info from special senses vision, hearing, balance via CN II (optic) and VIII (vestibulocochlear)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

sensory transduction: is

A
  • conversion of physical/ chemical stimuli from int/ext environment into neural signals that can effect physiological/ behavioural response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

sensory transduction: features

A
  • sensory receptors respond to specific modality (energy form)
  • transduce stimulus into form used by nervous system
  • can be simple (mechanical opening of ion channel)
  • transduction process can have amplification stage, esp if transduction is mediated by metabotropic/ G protein coupled receptor (eg. olfactory receptors)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

sensory transduction: pathway

A

stimulus - receptor - transduction - transmission - perception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

adequate stimulus: modality define

A
  • form of energy particular receptor can respond to
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

adequate stimulus: define

A
  • modality to which particular receptor responds best
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

exteroceptors: are

A

respond to stimuli orginating outside body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

exteroceptors: list

A
  • mechanoreceptors
  • photoreceptors
  • chemoreceptors
  • thermoreceptors
  • magnetoreceptors
  • electroreceptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

interoceptors: are

A
  • respond to stimuli originating inside body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

interoceptors: list

A
  • chemoreceptors (blood O2, CO2, pH)
  • baroreceptors (BP)
  • osmoreceptors (osmotic pressure - fluid balance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

proprioceptors: are

A

provide info about posture and position of body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

proprioceptors: list

A

mechanoreceptors

  • proprioception (joint/ limb position)
  • vestibular system (balance/ motion)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

sensory receptor type 1:

A
  • some sensory receptors formed from specialised ending on primary afferent sensory neuron
  • stimulus cause membrane ion channel to open/ close
  • graded potential (generator) -> can initiate AP in same cell
  • depolarising potentials will increase rate of AP generation
19
Q

sensory receptor type 2:

A
  • some sensory receptors are specialised cells separate from primary afferent neuron
  • graded potential generate in receptor cell (non-spiking)
  • voltage gated Ca channels open/ close and increase/ decrease rate of NT release
  • depolarising/ hyperpolarising graded potential is induced in primary afferent neuron -> increase/ decrease rate of firing AP
20
Q

trigger zones:

A
  • multipolar neurons: AP at axon hillock/ initial segment where axon joins soma
  • primary sensory afferent typically psuedounipolar cells -> dendrites (peripheral sensory) and axon terminal (central synaptic end)
  • trigger zone close to receptors/ dendrites (peripheral end)
21
Q

trigger zones: necessary why

A

graded potentials would not be able to travel all the way to soma (in dorsal root ganglion)

22
Q

receptor adaptation: features

A
  • receptors transduce sensory stimuli and respond w graded potentials proportional to stimulus strength and duration
  • some receptors respond w depolarisation of same magnitude for as long as stimulus is applied
  • most receptors reduce magnitude if sustained stimulus
23
Q

receptor adaptation: types

A
  • tonic (slow adapting)

- phasic (rapid adapting)

24
Q

tonic receptors: and eg

A
  • provide continuous updates for long lasting stimulus
  • muscle stretch (prevent over stretch)
  • merkel’s (pressure)
  • nociceptors
25
Q

phasic receptors: and eg

A
  • signal changes in stimulus intensity
  • many respond to cessation of stimulus w off response
  • olfactory receptors
  • touch (pacinian)
26
Q

stimulus intensity: rate (frequency) coding

A
  • larger stimulus - higher magnitude of potential - higher frequency of NT release
27
Q

stimulus intensity: population coding

A
  • stronger stimulus activates more receptors (recruitment)
  • more receptors of same afferent sensory neuron stimulated simultaneously
  • receptors on additional afferent sensory neurons that converge on same area of brain simultaneously
28
Q

stimulus localisation:

A
  • sensory systems organised spatiotopically (touch, vision)

acuity will depend on

  • size of receptive field/ unit
  • density of sensory units (spatial coverage)
  • degree of overlap in receptive fields of adjacent units
  • lateral inhibition
29
Q

define receptive field:

A
  • physical area within which receptors of single sensory unit can detect stimuli
30
Q

overlap of receptive field:

A
  • stimulus falling on overlapping portion of RF of two sensory receptors will stimulate them both neurons simultaneously (population coding)
31
Q

lateral inhibition: features

A
  • increases signal contrast for easy comparison
  • enhance transmission of focal signals, suppress transmission of diffuse signals
  • eg. of presynaptic inhibition
32
Q

lateral inhibition: centre surround RF

A
  • creates functional RF that has:
  • excitatory centre
  • inhibitory surround
33
Q

eg. tactile acuity:

A
  • ability to perceive two points pressed in skin
  • depends on density, RF size, overlap of tactile receptors (mechanoreceptors)
  • meissner’s corpuscles, merkel’s discs involved in fine touch perception and discrimination (small RF)
34
Q

two point discrimination threshold:

A
  • min distance btw points required for tactile discrimination
35
Q

sensory afferent neuronal pathways have two routes:

A
  • part of reflex arc

- relayed upward via ascending pathways -> further processing and possible conscious awareness

36
Q

sensory association areas of cortex:

A
  • identification and interpretation sensory info provided by primary cortical area
  • integration, association (memory) and behaviour
37
Q

define perception:

A
  • awareness and interpretation of sensory info
38
Q

perception: labelled lines

A
  • sensory pathways that transmit info regarding particular modality are specific to that modality
39
Q

Muller’s law (law of specific nerve energies):

A
  • sensation invoked by signals generated in receptor is determined by part of brain that they ultimately activate
40
Q

law of projections:

A
  • regardless of where a particular sensory pathway is stimulated along its course
  • conscious sensation generation is referred to location of receptor
41
Q

law of projections: eg.

A
  • phantom limb pain
  • L arm and chest during heart attack
  • pain signals from visceral pain receptors converge on same spinal neurons as somatic pain receptors
42
Q

inadequate stimulus of sufficient strength may stimulate receptors to respond to inappropriate modalities:

A
  • excessive pressure (mechanical energy) on eye stimulate retinal photoreceptors that normally detect light
  • visual phenomenon (seeing stars)
43
Q

consequences of Muller’s law 2: synaesthesia

A
  • stimulation of one sensory modality eg. vision, evokes perceptual experiences in another, eg. hearing
  • cross talk btw sensory pathways in brain (hearing colours, seeing or smelling sounds, seeing letters as colours)

4. BIOL257 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions