Somatosensory Receptors Flashcards
Skin receptors - stimuli outside the body
Exteroreceptors
Muscle, tendon, joint receptors - awareness of body position and movements
Proprioceptors
Viscera receptors - monitor events within the body
Enteroreceptors
Receptors that detect chemicals
Chemoreceptors
A specialized neuron able to detect and react to light during vision
Photoreceptors
Detect mechanical forces
Mechanoreceptors
Detect changes in temperature
Thermoreceptors
Detect pain
Nociceptors
Slowly adapting - continous
Tonic
Rapidly adapting - onset and cessation of stimuli
Phasic
Ability to recognize objects by touch alone
Stereogenesis
Ability to recognize numbers or letters drawn on the skin, it requires memory
Graphesthesia
▫ Requires intact pathway from deep structures
▫ Low frequency 128 vibrations/second are associated with the light touch pathways
Vibration sense
The minimum distance needed between two stimuli to perceive them as two units.
Two-point dsicrimination
Which receptor has two-point discrimination?
Merkel’s receptors
The space or region over which a stimulus alters neuronal activity
Receptive Field (rf)
Sensory receptors convert a stimulus into a neural activity
Stimulus transduction
How does a sensory receptor convert a stimulus into a transduction?
Mechanoreceptors open ion channels -> receptor potential (rapid or slow) -> stimulus transduction
Type of Receptors that release neurotransmitters onto sensory neurons, initiating AP
Special sense receptors
ex: hair cells
Type of Receptors that have nerve endings in CT capsules
Complex neural receptors
Type of receptors that are neurons with free nerve endings - no capsule - unmyelinated
Simple receptors - slower conduction
Primary Sensory Neuron
First order neuron - DRG
Dermis is composed of what kind of receptors?
Mechanoreceptors - pressure stretch, vibration
Encapsulated Receptors:
Meissner’s
Pacinian’s
Ruffini’s
Un-encapsulated Receptors:
Merkel’s disks/cells
Hair follicle receptors
Found in glabrous skin, capsulated, rapid adapting, sensitive to light touch, small rf
Meissner’s corpuscles
Found in hairy and glabrous skin, capsulated, rapid adapting, large rf, lamellae
Pacinian’s corpuscles
Found in deep layer of dermis, hair and glabrous skin, slowly adapting, large rf deteching skin stretch and pressure and thermoreceptor
Ruffini’s corpuscles endings
Nonencapsulated, in basal cell layer of epidermis below glabrous skin of lips, genitalia, slowly adapting, small rf
Merkel’s receptors discs
Meshlike arrangement of axons around hair follicle - discrete tacile stimulating
fast and slow adapting
Hair follicle receptors
These corpuscles are important for sensing movement of an object across the skin
Meissner and Pacinian
These corpuscles provides input related to displacement and velocity of the stimulus
Signaling the pressure and shape of the object through the skin
Merkel and Ruffini
The body’s ability to transmit position sense
Proprioception
Types of proprioception
Conscious and unconscious
Detect muscle length
Muscle spindles
Detect muscle strength
Golgi tendon organs
Which adaption provide information regarding the dynamic aspect of kinesthesia
Rapid adapting
Which adaption provide information about static aspect of kinesthesia
Slow adapting
- Single row of central nuclei - Smaller and shorter than the nuclear bag fiber
Nuclear chain fiber
- Cluster of nuclei located in a bag-like dilation at the center of the fiber
- Largest intrafusal fiber
Nuclear bag fiber
What type of endings do primary afferents type Ia have?
Annulospiral endings
What type of endings do secondary afferents have?
Flower spray endings
Stretch reflexis is also known as the:
Myotatic Reflex
What fiber type is an extrafusal skeletal muscle fiber?
A-alpha
What fiber type is an intrafusal muscle fiber?
A-gamma
What fiber type is an preganglionic autonomic fiber?
B
What fiber type is an postganglionic autonomic fiber?
C - unmyelinated
