Sensory and Motor Sysytems Flashcards
What are somatic senses?
The perception of physical sensations arising from the body’s surface or musculoskeletal system
What is the receptive field of sensory neurons?
The specific area of sensory space where a stimulus will alter the neuron’s activity
What do convergence receptive fields result in?
Two stimuli that are within the same secondary receptive field are perceived as single points
What do small receptive field result in?
Two stimuli activate seperate pathways to the brain resulting in two point discrimination
What are chemoreceptors?
Receptors that detect change in chemical composition
What are mechanoreceptors?
Receptors that detect pressure
What are photoreceptors?
Receptors that detect light
What are thermoreceptores?
Receptors that detect change in temperature
What are pacinian corposcle?
Sensory receptors in the skin that detects vibrations
What are merkel receptors?
Sensory receptors in the skin that detect steady pressure and texture
What are meissner’s corpuscle?
Sensory receptors in the skin that detect flutter and stroking movements
What are ruffini corpuscle?
Sensory receptors in the skin that detect skin stretch
What is noxious stimuli?
Strong, potentially damaging stimuli that results in pain
What detects hair movement?
Free nerve endings at the hair root
What is piezo2?
An excitatory ion channel gated by mechanical forces that detects changes in membrane tension
What type of ion channel is required for merkel receptors?
Piezo2
What temperature do cold receptors detect?
<37 degrees celsius
What temperature do warm receptors detect?
> 45 degrees celsius
What do temperature receptors rely on?
Transient receptor potential channels
What nerves sense pain?
Nociceptors which are free nerve endings
What tissue does not have pain receptors?
The nervous system
What type of fibre results in fast pain?
A delta fibres
What type of fibre results in slow pain?
C fibres
What type of fibre results in an itch?
C fibres in skin stimulated by histamine
What do nociception receptors rely on?
Transient receptor potential channels
What are TRPV1 channels?
Found on capsaicin receptor - heat activated ion channel
What are TRPM8 channels?
Found on menthol receptors - cold activated channel
What are TRPA1 channels?
Found on wasabi receptor - chemoreceptor for irritants
What does modality in neurons refer to?
Which sensory neurons are activated and where they terminate in the brain
What does location in neurons refer to?
Which receptive fields are activated
What is lateral inhibition?
Activated neuron reduces the activity of its neighboring neurons, enhancing contrast and sharpening sensory input
What does intensity in neurons refer to?
- Number of receptors activated - population coding
- Frequency of action potential - frequency coding
What does duration in neurons refer to?
The duration of action potential firing
What are tonic receptors?
Receptors which are slow to adapt
What are phasic receptors?
Receptors which are fast to adapt
Where is the synapse of the primary neurons and secondary neurons?
In the spinal cord or medulla
Where do all secondary neurons cross?
The midline
Where is the synapse of secondary neurons and tertiary neurons?
In the thalamus
Where do all somatosensory pathways terminate?
In the primary somatic sensory cortex
