principles of sensory systems

Question 1

what are 3 common steps for conservation of sensory processing?

Answer 1

• physical stimulus
• transform stimulus into nerve impulses (by sensory receptors in PNS)
• perception of sensation (CNS)

Question 2

structure of sensory receptors?

Answer 2

receptors can be cells not just proteins
- sensory receptor cells also have sensory receptors proteins (e.g. ion channels and G-protein coupled receptors)

Question 3

what are the sensory modalities (types)?

Answer 3

vision, smell, taste, hearing, touch, balance, thermal senses, pain, proprioceptors

Question 4

what is the stimulus, receptor and location for hearing?

Answer 4

stimulus - mechanical
receptor - mechanoreceptor
location - inner ear - cochlea

Question 5

what is the stimulus, receptor and location for balance?

Answer 5

stimulus - mechanical
receptor - mechanoreceptor
location - inner ear

Question 6

what is the stimulus, receptor and location for vision?

Answer 6

stimulus - light
receptor - photoreceptor
location - retina

Question 7

what is the stimulus, receptor and location for touch?

Answer 7

stimulus - mechanical
receptor - mechanoreceptor
location - skin

Question 8

what is the stimulus, receptor and location for temperature?

Answer 8

stimulus - thermal
receptor - thermoreceptor
location - skin

Question 9

what is the stimulus, receptor and location for pain?

Answer 9

stimulus - mechanical, thermal, chemical
receptor - nociceptor
location - skin, internal organs

Question 10

what is the stimulus, receptor and location for proprioception?

Answer 10

stimulus - mechanical
receptor - mechanoreceptor
location - muscles, tendons, joints

Question 11

what is the stimulus, receptor and location for olfaction?

Answer 11

stimulus - chemical
receptor - chemoreceptor
location - nasal cavity

Question 12

what is the stimulus, receptor and location for taste?

Answer 12

stimulus - chemical
receptor - chemoreceptor
location - tongue, pharynx, palate, epiglottis

Question 13

general process of stimulus to CNS?

Answer 13

1. stimulus activates sensory receptor protein
2. change in membrane permeability
3. graded receptor potential develops (voltage change)
4. neurotransmitter released onto afferent neuron terminals
5. action potential generates in afferent neuron which propagates to CNS where info is integrated
   (some neurons skip neurotransmitter, they can detect stimulus and generate action potential)

Question 14

different between graded vs action potential

Answer 14

• graded receptor potentials increase in size in response to increases in stimulus amplitude
• action potentials always same size but have threshold for activation

Question 15

what type of information can sensory receptors convey?

Answer 15

• modality
• location
• intensity
• timing

Question 16

what is sensory transduction?

Answer 16

converting energy from the environment into electrochemical signals in sensory receptors

Question 17

how is stimulus modality encoded in CNS?

Answer 17

labelled line code:
- axons of afferent neuron is a modality specific line of communication
- axons made connections with specific areas in CNS

Question 18

what happens if labelled line code is faulty?

Answer 18

synesthesia - stimulation of one sensory pathway leads to experiences in another pathway

Question 19

what is a receptive field?

Answer 19

region of sensory space where stimulus can influence activity of sensory receptor (conveys location of stimulus)

Question 20

what is a receptive field in the somatic system (touch)?

Answer 20

region of skin innervated by the terminals of the receptor neuron

Question 21

how do action potentials code increase in graded receptor potential?

Answer 21

increased frequency of action potentials

Question 22

what is sensory threshold?

Answer 22

lowest stimulus strength that can be detected (e.g. quietist sound you can hear)

Question 23

what are phasic receptors?

Answer 23

rapidly adapting receptors
- respond at the beginning and end of a stimulus

Question 24

what are tonic receptors?

Answer 24

slowly adapting receptors
- respond to prolonged stimulation

Question 25

definition of adaptation

Answer 25

decrease of firing potential in response to continuous stimulus

Question 26

what determines stimulus duration?

Answer 26

adaptation rates of receptors

Question 27

what determines onset timing?

Answer 27

when the stimulus is received by the receptor and causes it to fire