BMS11004 - WEEK 7 WEDNESDAY

Question 1

name 3 common steps of sensory processing in all systems

Answer 1

physical stimulus transformed into nerve impulse by PNS, evoking response to signal in form of perception of sensation (CNS)

Question 2

define sensory transduction

Answer 2

converting energy from environment into electrochemical signals in sensory receptors (both in forms of GP, AP)

Question 3

explain structure of sensory receptor protein

Answer 3

contain ion channels and GPCRs common to many bodily functions
GPCR detect photons in retina, odorate mol in olfaction

Question 4

name the 5 traditional senses, and other sense

Answer 4

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

Question 5

what is the stimulus and receptor for hearing

Answer 5

mechanical, mechanoreceptor

Question 6

what is the stimulus and receptor for balance

Answer 6

mechanical, mechanoreceptor

Question 7

what is the stimulus and receptor for vision

Answer 7

balance, photoreceptor

Question 8

what is the stimulus and receptor for touch

Answer 8

mechanical, mechanoreceptor

Question 9

what is the stimulus and receptor for temperature

Answer 9

thermal, thermoreceptor

Question 10

what is the stimulus and receptor for pain

Answer 10

mechanical, thermal, chemical, nociceptor

Question 11

what is the stimulus and receptor for proprioception

Answer 11

mechanical, mechanoreceptor

Question 12

what is the stimulus and receptor for olfaction

Answer 12

chemical, chemoreceptor

Question 13

what is the stimulus and receptor for taste

Answer 13

chemical, chemoreceptor

Question 14

outline sensory receptor propagation

Answer 14

stimuli activate sensory receptor, alters membrane permeability and sensory cell develop receptor potential
NT released onto afferent neuron terminal (or skipped, and AP generated in afferent neuron terminal)
AP propagate to CNS, integrate information

Question 15

compare AP, GP

Answer 15

GP increase in size in response to stimuli amplitude increase, but AP same size with threshold for activation

Question 16

outline roles of AP, GP in muscles

Answer 16

small stretch opens membrane, ions move in, small depolarisation but not enough to trigger an AP (small GP dont cause AP)
if bigger GP, meet threshold, trigger AP

Question 17

direct neuronal activation in olfactory receptors - explain process

Answer 17

olfactory receptor cell in olfactory epithelium has dendrites into mucus
enough odorant molecule bind cause ion influx, depolarisation, GP in dendrite, travel down neuron
large enough cause soma depolarisation, triggers AP (travels to olfactory bulb)

Question 18

summarise sensory transductions

Answer 18

energy from environment converted into electrochem signal in sensory receptors

Question 19

what 4 types of info can sensory receptors convey

Answer 19

modality, location, intensity, timing

Question 20

what is labelled line code for stimulus modalities

Answer 20

receptor selective for specific types of stimulus energy
axons of receptor or associated afferent neuron act as modality specific communication line into CNS

Question 21

what does stimulating afferent neurons in labelled line codes cause

Answer 21

perception of associated sensation, faults cause synaesthesia (perceive one stimulus as wrong, when fault in axonogensis, axons finding where they need to connect to)

Question 22

what does spatial arrangement of activated receptors in sense organs mean

Answer 22

give info on stimulus

Question 23

what are receptive fields

Answer 23

regions of skin which are innervated by terminals of receptor neuron, with receptive field size relevant to areas importance

Question 24

explain size of receptive fields importance

Answer 24

larger stimulus activate more neuron
small object in hand activate few receptive fields
receptive field of photoreceptor is region of visual field projected onto it

Question 25

outline stimulus intensity

Answer 25

total amount of stimulus energy delivered to receptors

Question 26

outline sensory threshold

Answer 26

lowest stimulus strength that can be detected

Question 27

what is stimuli intensity determined by

Answer 27

response amplitude of receptor, so firing frequency of afferent neurons
small stimuli activate small AP= less NT released
larger stimuli = bigger AP, more NT

Question 28

what determines stimulus duration

Answer 28

adaption rate of receptors (in response to continuous stimuli, AP firing rates decreases)

Question 29

what are slowly adapting receptors

Answer 29

tonic receptors that respond to prolonged stimulation

Question 30

what are rapidly adapting receptors

Answer 30

phasic receptors that respond at beginning and end of stimulus
when initially sit down, sense it, then over time adapts so sensor stops sensing signal and passing it on