PHGY 215 Module 3 Exam Questions and Answers Fully Solved Latest Version 2025-2026
Transdunction - Answers conversion from an environmental signal to an electrical signal
4 afferent neuron properties (allows CNS to accurately differentiate incoming stimuli)
- MIDL - Answers 1. Modality (photoreceptors, mechanoreceptors, thermoreceptors,
chemoreceptors)
2. Intensity.
3. Duration
4. Location (receptive field, multiple sensors - 2 eyes & ears, gradients - a smell intensifies as
you move closer to it)
Receptor activation - Answers when receptors are stimulated, membrane permeability is altered
causes nonselective ion channels too open
when cation enter the neuron, depolarization occurs
Receptor potential - Answers change in potential due to the incoming signal in specialized
receptors
Generator potential - Answers change in potential due to an incoming signal from a separate
cell to the ending of an afferent neuron
Graded potential - Answers happens from postsynaptic neuron to axon hillock
if graded potential are of sufficient magnitude and can reach axon hillock in a given amount of
time (before it degrades) AP is initiated down the axon
Specialized afferent endings - Answers receptor potential can cause afferent nerve fibres to
reach threshold triggering AP
Separate receptor cells - Answers when receptor potential is strong enough, it will cause NT to
be released which opens Na+ gated channels on afferent neuron
if threshold is reach, initiation of AP will take place
Tonic receptors (and example) - Answers slow adapting or don't adapt at all
ex. muscle stretch receptors, pain receptors
Phasic receptors (and example) - Answers fast adapting
ex. Lamellar corpunscles or Pacinian corpuscles (mechanicoreceptors) - wearing a watch
, Nociceptors - Answers pain receptors
3 types of nociceptors - Answers 1) Mechanical (respond to physical damage cutting/crushing)
2) Thermal (responds to temp, especially heat)
3) chemical (respond to harmful chemicals)
What NT get released (at the end of an afferent axon) in response to pain - Answers substance
P and glutamate (work together)
propagate the signal to the brain for further processing
Hypothalamus/limbic system response to pain - Answers emotional and behavioural
Cortex response to pain - Answers localizing the pain
Thalamus response to pain - Answers perception of pain
Reticular formation of pain - Answers increases the level of alertness and awareness of painful
stimuli
AMPA receptors - Answers when glutamate is released from afferent cell
AMPA activate which leads to permeability changes that generate greater AP in the dorsal
neuron and send the signal to higher brain centres
NMDA receptors - Answers once activated by glutamate, the receptors allow calcium to enter
the neuron
this leads to activation of a second messenger that results in neurons being more excitable
than normal
(this explains why injured areas are more sensitive to pain - clothing rubbing against a sunburn)
How is pain stopped? - Answers endogenous and exogenous opioids
Endogeneuous opioids - Answers substances that are produced by the body and have
painkilling effects (i.e. endorphines)
Exogeneous opioids - Answers substances that aren't produced by the body and have painkilling
effects (morphine)
A-delta fibres - Answers fast pain fibres
quick, intense pain
temperature, chemical and mechanical stimuli
Transdunction - Answers conversion from an environmental signal to an electrical signal
4 afferent neuron properties (allows CNS to accurately differentiate incoming stimuli)
- MIDL - Answers 1. Modality (photoreceptors, mechanoreceptors, thermoreceptors,
chemoreceptors)
2. Intensity.
3. Duration
4. Location (receptive field, multiple sensors - 2 eyes & ears, gradients - a smell intensifies as
you move closer to it)
Receptor activation - Answers when receptors are stimulated, membrane permeability is altered
causes nonselective ion channels too open
when cation enter the neuron, depolarization occurs
Receptor potential - Answers change in potential due to the incoming signal in specialized
receptors
Generator potential - Answers change in potential due to an incoming signal from a separate
cell to the ending of an afferent neuron
Graded potential - Answers happens from postsynaptic neuron to axon hillock
if graded potential are of sufficient magnitude and can reach axon hillock in a given amount of
time (before it degrades) AP is initiated down the axon
Specialized afferent endings - Answers receptor potential can cause afferent nerve fibres to
reach threshold triggering AP
Separate receptor cells - Answers when receptor potential is strong enough, it will cause NT to
be released which opens Na+ gated channels on afferent neuron
if threshold is reach, initiation of AP will take place
Tonic receptors (and example) - Answers slow adapting or don't adapt at all
ex. muscle stretch receptors, pain receptors
Phasic receptors (and example) - Answers fast adapting
ex. Lamellar corpunscles or Pacinian corpuscles (mechanicoreceptors) - wearing a watch
, Nociceptors - Answers pain receptors
3 types of nociceptors - Answers 1) Mechanical (respond to physical damage cutting/crushing)
2) Thermal (responds to temp, especially heat)
3) chemical (respond to harmful chemicals)
What NT get released (at the end of an afferent axon) in response to pain - Answers substance
P and glutamate (work together)
propagate the signal to the brain for further processing
Hypothalamus/limbic system response to pain - Answers emotional and behavioural
Cortex response to pain - Answers localizing the pain
Thalamus response to pain - Answers perception of pain
Reticular formation of pain - Answers increases the level of alertness and awareness of painful
stimuli
AMPA receptors - Answers when glutamate is released from afferent cell
AMPA activate which leads to permeability changes that generate greater AP in the dorsal
neuron and send the signal to higher brain centres
NMDA receptors - Answers once activated by glutamate, the receptors allow calcium to enter
the neuron
this leads to activation of a second messenger that results in neurons being more excitable
than normal
(this explains why injured areas are more sensitive to pain - clothing rubbing against a sunburn)
How is pain stopped? - Answers endogenous and exogenous opioids
Endogeneuous opioids - Answers substances that are produced by the body and have
painkilling effects (i.e. endorphines)
Exogeneous opioids - Answers substances that aren't produced by the body and have painkilling
effects (morphine)
A-delta fibres - Answers fast pain fibres
quick, intense pain
temperature, chemical and mechanical stimuli
