Sensory Transduction Flashcards
How does the nervous system encode the strength of a stimulus?
Neural encoding: Frequency of action potentials
What happens if a membrane is held at above threshold level?
Same effect as a second, larger stimulus
Relative refractory period reduced
What is the difference between neural enciding in somatosensory/olfactory receptors and other receptors?
Somatosensory/olfactory - receptor neuron performs stimulus translation and neural encoding
Other systems use receptor cells for translation and neurons for encoding
What types of neurons have free nerve endings?
Sensory neuron
What are the functional characteristics of free nerve endings?
Pain receptors (nociceptors) Most common type Slow to adjust
What type of nerves have encapsulated endings?
Skin and joint capsules
Skeletal muscle
Muscle-tendon junctions
What are specialised receptor cells?
Very specific
Connected to a bipolar cell
Which is detected more easily by skin receptors: a finger or a hand?
Finger
A sensation that creates local deformation is more easily detected
What do mechanoreceptors detect?
Stretch, pressure and vibration
What do Pacinian Corpuscles do?
Detect pressure, vibration and limb movement
What do Meissner’s Corpuscles do?
Deform under pressure
Sensitive to light touch, pain and temperature
Fast adapting
Where are Pacinian Corpuscles found?
Skin, mesenteries, joint capsules
Where are Meissener’s Corpuscles found?
Near skin surface
Fingertips, lips, orifaces, nipples
What do Pacinian Corpuscles look like?
Egg
Many layers
What do Meissner Corpuscles look like?
Capsule containing lamellar cells
