19/ principles of sensory systems

Question 1

3 common steps of processing sense

Answer 1

• physical stimulus - chemical, sound waves, physical, photons
• transform stimulus into nerve impulses - sensory receptors in the peripheral ns
• evoke a response to the signal in the form of perception of sensation - cns

Question 2

true or false: sensory receptors are proteins on cells

Answer 2

• false
• cells not just proteins

Question 3

what is sensory transduction

Answer 3

• energy/signal from the environment turned into electrochemical signals in sensory receptors

Question 4

what is specificity for sensory modalities achieved by

Answer 4

structure and position of the sensory receptor

Question 5

9 senses

Answer 5

• vision, smell, taste, hearing
• balance, proprioception, touch
• thermal senses, pain

Question 6

why is touch not considered a special sense

Answer 6

• all other senses have specialised structures
• skin does other things - barrier

Question 7

modality, stimulus, receptor, location

Answer 7

• hearing, mechanical, mechanoreceptor, inner ear - cochlea
• balance, mechanical, mechanoreceptor, inner ear
• vision, light, photoreceptor, retina
• touch, mechanical, mechanoreceptor, skin
• temp, thermal, thermoreceptor, skin
• pain, mechanical thermal chemical, nociceptor, skin internal organs
• proprioception, mechanical, mechanoreceptor, muscles tendons joints
• olfaction/smell, chemical, chemoreceptor, nasal cavity
• taste, chemical, chemoreceptor, tongue pharynx palate epiglottis

Question 8

example of directional neuronal activation - olfactory receptors

Answer 8

• ion influx causes memb depolarisation and a graded receptor potential develops in a cilium
• large enough receptor potential cause depolarisation in the cell soma, triggering ap sent to olfactory bulb

Question 9

relationship between sensory receptor cells and afferent neurons

Answer 9

• sensory receptor cells can be the primary afferent neuron or can release nts to the primary afferent neuron

Question 10

what 4 types of info can sensory receptors convey

Answer 10

• modality
• location
• intensity
• timing

Question 10

how does labelled line code code stimulus modality

Answer 10

• receptor is selective for one type of stimulus energy
• the axons of the receptor acts as a modality specific line of communication
• axons from these neurons make connections w specific areas in the cns - perception of associated sensation

Question 10

what is the receptive field in the somatic system and visual system

Answer 10

• somatic: region of skin innervated by terminals of the receptor neuron. each neuron has its own receptive field.
• visual: receptive field of a photoreceptor is the region of the visual field projected onto that receptor
• in both, dif areas of body have dif receptive fields. hand want tiny receptive fields - precise but back less important

Question 11

what is faulty in synaesthesia

Answer 11

• labelled line code
• defects in formations of axons - axons connect to the wrong things

Question 12

what is stimulus intensity

Answer 12

• total amount of stimulus energy delivered to the receptor
• lowest stimulus strength that can be detected (passed on) is sensory threshold
• intensity determined by response amplitude of the receptor and thus firing frequency of afferent neurons

Question 13

stimulus timing - onset and duration. adaptation

Answer 13

• onset timing: determined by when stimulus energy is received by receptor and causes it to fire
• stimulus duration: determined by adaptation rates of receptors
• adaptation: in response to continuous stimuli firing rate of ap decreases

Question 14

stimulus timing - tonic and phasic receptors

Answer 14

• tonic: slowly adapting, respond to prolonged stimulation, rapid at start then more constant signals
• phasic: rapidly adapting receptors, respond at the beginning and end of a stimulus