Axons & Receptor Types Flashcards
Name the Skin & Muscle Axons that are most myelinated.
Aa & Group 1
What is the Diameter of Group 1/Aa axons?
13-20 um
What is the Diameter of Group 2/AB axons?
6-12 um
What is the Diameter of Group 3/Ad axons?
1-5 um
What is the Diameter of Group 4/C axons?
0.2-1.5
What is Conduction Speed of Group 1/Aa?
80-120 m/s
What is Conduction Speed of Group 2/AB?
35-75 m/s
What is Conduction Speed of Group 3/Ad?
5-30 m/s
What is Conduction Speed of Group 4/C?
0.5-2
What Sensory Receptors are Group 1/Aa used for?
Proprioceptors of Skeletal Muscle
What Sensory Receptors are Group 2/AB used for?
Skin mechanoreceptors
What Sensory Receptors are Group 3/Ad used for?
Pain & Temp
What Sensory Receptors are Group 4/C used for?
Itch, Pain & Temp
What type of sensation do Free Nerve Endings detect?
Pain; Adelta = Sharp pricking pain
C = Polymodal - Hot, Cold, Burning, Ache
What Axons are used for Free Nerve Endings?
Ad & C
Where are Free Nerve Endings found?
All skin types
Describe Adaptation & Activation Threshold for Free Nerve Endings
Slowly adapt
High Activation Threshold
Describe Composition of Merkel’s Discs
Nerve Ending + Specialised Epithelial Cell
Non-encapsulated endings
What Fibres Are Used for Merkel’s Discs?
ABeta
What do Merkel’s Discs detect?
Static Touch & Pressure
Where Are Merkel’s Discs found?
All skin types
Lips, Genitals & Extremities
Describe Adaptation & Activation Threshold for Merkel’s Discs
Slowly Adapting
Low Activation Thresh
Describe composition of Meissner’s Corpuscles
Encapsulated nerve endings
What do Meissner’s Corpuscles detect?
Changes in touch & pressure
What fibres do Meissner’s use?
ABeta
Where are Meissner’s found?
Glabrous Skin Types (Non-hairy)
Between Dermal Papillae
Fingers, Palms, Toes, Plantars
Describe Adaptation & Activation Threshold for Meissner’s Corpuscles
Rapidly adapting
Low Activation Thresh
