PHY2011 Lecture Notes - Lecture 14: Myelin, Axon Hillock, Depolarization
20 Jun 2018
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Week 5 L2 (T4L1) -basic principles of sensory processing
All senses have the same goal: take a physical stimulus, and convert it into a biological
response and send the information to the brain
The sensory system:
oPeripheral components (eyes, ears, nose, tongues etc)
oCentral components (brain, conversion of signal)
oMotor responses/ Learning and memory/ Other cognitive progresses
The Peripheral components
Accessory structures Translate the stimulus to the receptor cells
oFocus the light -lens
oAmplify the sound -auditory canal
Receptor cells Transduce stimulus to a biological response
oRetina
oCochlea
Afferent nerve fibres (output neurons) Transmit information to CNS in the form of APs
Receptors
Senses convey specific information due to specialised receptors
oIe. Vision -we see a particular range of the light spectrum
Bees see more UV light than we can
Two types of receptors:
oNerve fibres with specialised endings
Dendrites designed to receive input from the physical energy of the
stimulus
Ie. Touch, body position, smell
oSpecialised receptor cells separate from nerve fibres
find more resources at oneclass.com
find more resources at oneclass.com
Cells that only detect stimulus, not to produce an AP
Ie. Taste, hearing, vision
oNote: vision is part of a third group that has a relay cell (intermediate) between
receptor and nerves
Classification
oBased on site of origin of stimulus
EXTEROCEPTION (Extero-receptors / Exteroceptors)
- The state of things in external world
PROPRIOCEPTION (Proprio-receptors / Proprioceptors)
- The relationship of our body to the world
- (position and movement of limbs & body in space)
INTEROCEPTION (Intero-receptors / Interoceptors)
- The state of things within the body
- Ie. Gasses in blood
oBased on the stimuli that activate them
MECHANO-RECEPTORS
- Respond to stretch or deformation
- Examples: Hearing, Balance, Blood pressure, Muscle stretch, Gut
filling, Proprioceptors
PHOTO-RECEPTORS
- Respond to Light
- Example: Vision
CHEMO-RECEPTORS
- Respond to chemicals
- Example: Taste, Smell, Blood gases, Osmoreceptors (osmolarity)
THERMO-RECEPTORS
- Respond to changes in temperature
- Example: Somatosensation
NOCI-RECEPTORS (NOCICEPTORS)
- Respond to painful / damaging stimuli
- Tells us about any of the other four, but only to extreme levels of
stimulus
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Week 5 l2 (t4l1) -basic principles of sensory processing. All senses have the same goal: take a physical stimulus, and convert it into a biological response and send the information to the brain. The sensory system: peripheral components (eyes, ears, nose, tongues etc, central components (brain, conversion of signal, motor responses/ learning and memory/ other cognitive progresses. Accessory structures translate the stimulus to the receptor cells: focus the light -lens, amplify the sound -auditory canal. Receptor cells transduce stimulus to a biological response: retina, cochlea. Afferent nerve fibres (output neurons) transmit information to cns in the form of aps. Senses convey specific information due to specialised receptors: ie. Vision -we see a particular range of the light spectrum. Bees see more uv light than we can. Two types of receptors: nerve fibres with specialised endings. Dendrites designed to receive input from the physical energy of the stimulus. Touch, body position, smell: specialised receptor cells separate from nerve fibres.
