Unit 4 Somatasensory Flashcards
Describe what is meant by the terms: sensory organ, receptor cell, and stimulus
Sensory organ:
a part of your body that you use to see, hear, smell, taste, or feel things.
Receptor cells: proteins embedded in the plasma membrane of target cells
Stimulus: a thing or event that evokes a specific functional reaction in an organ or tissue
Describe the concept of labeled lines and the way action potential frequency can code for intensity.
Labeled lines: particular neurons are labeled for distinctive sensory input
Action potential frequency can be coded using adaptation
Describe the concepts of sensory transduction and receptor potentials
Sensory transduction Converts stimulus energy into a change in membrane potential and possibly a neural impulse.
Receptor potentials is a local change in the membrane potential of a receptor cell that occurs in response to a sensory stimulus.
Describe adaptation and central modulation of sensory information
Adaption makes us good at detecting change
central modulation of sensory information is the organization of sensory information
Explain receptive fields
the stimulus region that affects the activity of a neuron in the sensory system
Describe the terms polymodal and synesthesia
Polymodal: neurons respond to more than one stimulus modality.
Synesthesia: stimulus from one modality evokes a perception from a different modality
Describe the process of sensory transduction for light touch
The transduction of a physical force on the skin into an electrical signal. The receptor on the skin for light touch is the Markel’s disc
List the different sensory receptors in the skin and their characteristics. Pacinian corpuscle, Meissner’s corpuscle, Merkel’s discs, Ruffini’s ending.
Pacinian corpuscle: Deep pressure and vibrations
Meissners corpuscle: fine touch and vibrations
Markel’s disc: fine touch and points and edges
Ruffini’s ending: skin stretching
Describe how sensory information regarding touch is transmitted to the brain
1) Information about touch stimuli travels to the brain via the dorsal columns
2) Axons from the dorsal columns project to the medulla. The medullar neurons project to the thalamus. The thalamic neurons send this information to the somatosensory cortex
3) The somatosensory cortex (S1, post-central gyrus) is organized in a topographic fashion
Discuss the concept of plasticity in the somatosensory cortex
the ability of neural networks in the brain to change through growth and reorganization
Describe the possible adaptive purposes of pain
Learning what is dangerous and what to avoid
Describe how damaged tissue generates a pain signal
Tissue damaged is sensed by special receptors called nociceptors. They send a signal to the spinal cord then to the brain.
What is the significance of the Nav1.7 channel in pain sensory
Sodium channels control the entry of charged sodium ions. By permitting an influx of sodium ions in response to stimulus
Describe how changes in temperature are detected
free nerve endings have temperature-gated ion channels: TRPV1 channels open in response to elevated temperatures. CMR1 channels open in response to cool temperatures.
Describe how information regarding temperature and pain is transmitted to the brain
It is transmitted to the brain using the anterolateral system and the spinothalamic tract
