Neurophysiology 1 : Organization And Receptors (Lecture 75) Flashcards
What is the function of the nervous system?
Receive sensory information
Integrate and process information
Decide if a motor output will occur (Not all sensory stimuli require a motor output)
What is the definition of a sensory receptor?
Specialized to detect a particular stimulus modality
What do specialized sensory cells synapse with?
Primary afferent neurons
Afferent neuroses have ______ nerve endings. They also have _____ nerve endings.
Free
Modified
Describe the modified nerve endings that afferent neurons have?
Combined with other accessory tissues that enhance response to a certain type of stimulus
ALL receptors are able to perform _________.
Transduction
All receptors have _______ _______ ________ that open based upon specific types of stimulus/
Modality gated channels
Receptors convert the ________ into ______ ______.
Stimulus into action potentials
What is stimulus intensity of a receptor encoded by?
Rate and frequency of Action Potential
What are the physical characteristics of receptors?
Encapsulated or free nerve endings
What are stimulus durations encoded by?
Receptor adaptation
Tonic receptors do not rapidly ________. What is an example?
Adapt
Proprioceptors
Adaption of receptors =
Decreased sensitivity to continuous stimuli
Phasic receptors adapt _________. What are examples?
Rapidly
Pacing an and Meissner’s corpuscles
Stimulus type encoded by ______
Modality
What is the response to specific type of stimulus based on?
“Labeled line” code
What are some classifications of receptors by modality? (7)
Thermoreceptors (temperature)
Mechanoreceptors (movement of cell membrane)
Photoreceptors (light)
Chemoreceptors (chemical)
Barorecptors (hydrostatic pressure/stretch)
Proprioceptors (body position)
Nociceptors (noxious stimuli)
What does the golgi tendon organ detect?
Muscle contraction
What does the muscle spindle detect?
Muscle stretch
What are Proprioceptors?
Cutaneous mechanoreceptors
What are examples of joint capsule mechanoreceptors?
Pacinian and Ruffin
What are examples of muscle and tendon mechanoreceptors?
Golgi tendon organ and muscle spindles
Where do somatosensory signals originate? What do they detect?
Originate: peripheral sensory receptors
Detect: changes in environmental stimuli
Where do viscerosensory signals originate from? What do they detect?
Originate: viscera
Detect: changes in internal stimuli
Organ dispensation, ischemia, intestinal pain (conscious)
Autonomic Nervous System inputs and reflexes
Where do special sense signals (vision, hearing, taste, olfaction) originate from?
Originate: special sensory organs localized to the head
What is touch/pressure/vibration sensed by? Characteristics?
Sensed by Mechanoreceptors
Adaptable, encapsulated/unencapsulated
What are meissner’s corpuscles responsible for?
Transmitting sensation of light touch, pressure and texture
What are pacinian corpsucles responsible for?
Transmitting sensation of deep pressure, tickle, and vibration
What are Merkel’s disks responsible for?
Transmitting sensation of touch
What are Ruffini’s corpuscle responsible for?
Stretch
What is temperature sensed by?
Receptor potential channels (TRP) on free nerve endings
What is a target for pain relieving medicine?
TRP family
Characteristics of nociceptors?
Free nerve endings
TRP family
Lightly myelinated (A-delta) or unmyelinated (C fibers)
Not adaptable
What are nocicpetors?
Sensitive to multiple extreme or potentially damaging stimuli
What are chemical nociceptors sensitive to?
Intracellular contents, inflammatory mediators
