Unit 1 Somatic Senses Flashcards
(123 cards)
All sensory systems mediate what 4 attributes of a stimulus no matter what type of sensation?
- Modality
- Location
- Intensity
- Timing
Describe transduction
When a stimulus is changed into an electrical signal.
What are the two systems of classifying nerve fibers?
Erlanger’s and Lloyds
How does myelination effect conduction velocity?
Myelination increases conduction velocity by 6 fold
An unmyelinated fiber 5 microns in diameter conducts a signal how fast?
5m/second
How fast does a myelinated fiber 5 microns in diameter conduct a signal?
30m/second
Using Erlanger’s system, what is the diameter of a type A alpha fiber?
8 to 20 microns
Using Erlanger’s system, what is the diameter of type A beta fibers?
5 to 12 microns
Using Erlanger’s system, what is the diameter of a type A gamma fiber?
2 to 8 microns
Using Erlanger’s system, what is the diameter of a type A delta fiber?
1 to 5 microns
Using Erlanger’s system, what is the diameter of a type B fiber?
1 to 3 microns
Using Erlanger’s system, what is the diameter of type C fibers?
<1 microns
Using Lloyd’s system, what is the diameter of type I fibers?
12 to 20 microns
Using Lloyd’s system, what is the diameter of type II fibers?
4 to 12 microns
Using Lloyd’s system, what is the diameter of type III fibers?
1 to 4 microns
Using Lloyd’s system, what is the diameter of type IV fibers?
<1 micron
Describe the labeled line principle.
The specificity of nerve fibers transmitting only one modality of sensation.
Describe adaptation
When a neuron experiences a sustained stimulus it will show a decreased firing rate over time. This is known as adaptation.
Describe slow adapting receptors
Continuous information relatively non adapting in response to a sustained stimulus
Describe what fast adapting receptors do.
Fast adapting receptors react strongly when a change is taking place.
Name two slow adapting receptors.
- Merkel’s discs
- Ruffini corpuscles
Name two fast adapting receptors.
- Pacinian corpuscles
- Meissner’s corpuscles
Describe the receptive field of Merkel’s Discs.
Merkel’s Discs have a punctate receptive field. Meaning its studded or marked with tiny dots or holes.
How are Ruffini corpuscles activated?
Ruffini corpuscles are activated by stretching the skin.