Modalities of sensation Flashcards
What is a tonic receptor?
Slowly adapting receptors, responding to a stimulus as long as it persists and producing a continuous high frequency of action potentials
What is a phasic receptor?
Rapidly adapting receptor, responding quickly to stimuli but stopping upon continual stimulation. Therefore action potential frequency decreases during prolonged stimulation
Are nociceptors phasic or tonic?
Phasic
What do nociceptors respond to?
Noxious stimuli
Where are nociceptors found?
On the ends of type A gamma fibres and Cfibres
What are the four types of nociceptors?
Mechanical, thermal, chemical, polymodal
Are merkel’s discs tonic or phasic?
Tonic
Are meissner’s corpuscles tonic or phasic?
Phasic
Are pacinian corpuscles tonic or phasic?
Phasic
Are ruffini end-organs tonic or phasic?
Tonic
Where are merkels discs found?
In the skin, near the border of the dermis and epidermis
Where are meissner’s corpuscles found?
Dermis of the skin, namely the palms, soles of the feet, lips and tongue
Where are pacinian corpuscles found?
The dermis, hypodermis, ligaments and external genitalia
Where are ruffini end-organs found?
Dermis
Where are muscle spindles found?
Skeletal muscle
Where are golgi tendon organs found?
Skeletal muscle
What are the different mechanoreceptors ?(6)
Merkels discs Meissners corpuscles Pacinian corpuscles Ruffini end-organs Muscle spindles Golgi tendon organs
What do merkel’s discs respond to?
Pressure and texture and shape of objects
What do meissner’s corpuscles respond to?
Two-point discrimination and fine touch
What do pacinian corpuscles respond to?
Pressure changes and vibration
What do ruffini end-organs respond to?
Stretch
What do muscle spindles respond to?
Stretch
What do golgi tendon organs respond to?
Stretch
Are there more warm or cold receptors?
Cold receptors
What are the 5 components of a reflex arc?
Receptor (muscle spindle), afferent fibre (muscle spindle afferent), integration centre (lamina IX of spinal cord), efferent fibre (Alpha motoneurone), effector (muscle)
