S&F of Peripheral Sensory Receptors Flashcards
Receptive field of Merkel discs?
Multiple small spots
Do Pacinian corpuscles have a slowly or rapidly adapting response?
Rapidly adapting
Which type of mechanoreceptor?
- Ending is encapsulated
- myelinated axon surrounds collagen fibrils
Ruffini endings
Which type of mechanoreceptor?
- Encloses a stack of flattened epithelial cells
- sensory terminal entwined between layers
- axon is myelinated
Meissner’s corpuscles
Which type of mechanoreceptor?
- Fluid filled capsule wrapped around bare nerve ending
- filters out sustained stimuli
- myelinated axon
Pacinian Corpuscles
Easy to localize? A-Mechanonociceptors
yes
What is the receptive field of Ruffini Endings?
Large and diffuse
Cooling receptors: myelinated or unmelinated axons?
Myelinated
Which nociceptor responds to intense mechanical force, high heat (> 45°C), noxious chemicals (bradykinin, histamine, etc.)?
C polymodal nociceptors
Easy to localize? C Polymodal nociceptors
No
C polymodal nociceptors: myelinated or unmyelinated axons?
unmyelinated (C-fiber)
What do Meissner’s corpuscles encode?
Low-frequency vibration
On/offset of skin indentation
What is the spatial summation code?
OVerall picture in brain is due to the sum of information provided by the different active and silent fibers
What percent of all sensory neurons in the DRG are nociceptors?
70%
Receptive field of Meissner’s corpuscles?
Single spot
Do Merkel discs have a slowly or rapidly adapting response?
Slowly adapting response
What do Merkel discs encode?
Amount of force
What are the superficial mechanoreceptors?
Merkel disks and Meissner’s corpuscles
Which type of mechanoreceptor?
Responds to high frequency vibration
Pacinian corpuscles
Do Ruffini Endings have a slowly or rapidly adapting response?
Slowly adapting, responds to stretching of skin
Having no sheath helps C polymodal nociceptors respond to what?
Inflammatory chemicals
Which receptors sense stretch of skin?
Ruffini Endings
Which type of mechanoreceptor?
Fine touch, 2-point discrimination, sense abrupt changes in edges (bumps, corners)
Help adjust grip and relase when lifting objects
Meissner’s corpuscles
What is the spatial summation code in relation to intensity of a stimulus?
The number of neurons firing
Do Messner’s corpuscles have a rapidly or slowly adapting response?
Rapidly adapting
Which type of mechanoreceptor?
Receptive field: Multiple small spots, high density in fingure tips, around mouth
Low density on back
Merkel disks
What is the receptive field of Pacinian corpuscles?
large and diffuse
Which type of mechanoreceptor?
Fine touch, 2-point discrimination; sharpest resolution of surface texture
Bumpy vs. smooth
Merkel disks
Which nociceptors are polymodal (many modes)?
C polymodal nociceptors
What is the rate code in relation to intensity of a stimulus?
Each neuron’s frequency of action potential firing
Which receptors help determine shape of grasped objects?
Ruffini Endings
A-Mechanonociceptors: myelinated or unmyelinated axons?
Myelinated
True or false
Both A-Mechanonociceptors and C polymodal nociceptors have:
- Free nerve endings
- Small receptive fields
- Slowly adapting responses
True
Receptive field of warming receptors?
Very small receptive fields
Which type of mechanoreceptor?
Most sensitive mechanoreceptor, even distribution throughout skin
Pacinian corpuscles
Which type of mechanoreceptor?
Several disks innervated by a single myelinated axon
Merkel disks
Which nociceptor responds to intense mechanical force and sometimes intense heat (>52 °C)?
A-mechanonociceptors
Warming receptors: myelinated or unmyelinated axons?
Unmyelinated (C FIBER!)
Do hair follicles have a slowly or rapidly adapting response?
Rapidly adapting response encodes velocity of hair momvement
