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Questions and Answers
What type of tactile sensation is characterized by a deformation of deeper tissues?
Which type of receptor is sensitive to the movement of objects over the skin and detects low-frequency vibration?
What is the characteristic of hair end-organ receptors?
What type of skin do Meissner's corpuscles receptors typically occur in?
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What is the characteristic of Meissner's corpuscles receptors?
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What is the common characteristic of all tactile receptors?
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What is the main function of pain receptors?
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What happens to the structure of mechanoreceptors when they are stimulated?
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What is the term for receptors that send impulses as long as the stimulus is present?
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What happens to the sodium channels in nerve fibers during adaptation?
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At which level can adaptation occur?
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What is the term for receptors that respond to rapid changes in the environment?
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What is the primary function of free nerve endings in tactile sensation?
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Which type of nerve fiber transmits signals from Pacinian corpuscles?
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What is the characteristic of Merkel's disc in terms of adaptation?
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Where are Ruffini's endings typically located?
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What is the characteristic of Pacinian corpuscles in terms of their structure?
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What is the classification of tactile receptors based on?
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Study Notes
Tactile Receptors
- Free nerve endings are widely distributed and detect touch, pressure, and some detect tickle and itch.
- They are innervated by type A-delta-myelinated or type C nerve fibers, with type A delta being slower and type C being the slowest.
Types of Tactile Receptors
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Pacinian corpuscles detect vibration and deep pressure, are encapsulated by concentric lamellae, and are located immediately beneath the skin in fascial tissues.
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They are rapidly adapting and stimulated by rapid local compression of tissues.
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Merkel's discs (expanded tip tactile receptors) detect steady-state, continuous touch, and have expanded dendritic endings.
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They are numerous in non-hairy skin, initially strong, and then partially adapting to a weaker signal.
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Ruffini's endings detect continuous deformation (e.g. prolonged touch and pressure), have elongated capsules, and are located in the deeper layers of skin and internal tissues.
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They adapt slowly and are found in joint capsules.
Other Concepts
- Classification of tactile receptors according to adaptation response and receptive fields:
- Fast adapting vs. slow adapting
- Receptor field type 1 vs. type 2
Pressure, Vibration, and Touch
- Pressure is deeper and involves deformation of deeper tissues.
- Vibration is rapidly repetitive signals and is basically touch with a pattern.
- Touch is superficial and involves stimulation of receptors in the skin and tissues directly under the skin (shallow).
Other Tactile Receptors
- Hair end-organ detects movement of objects on the body and initial contact, is rapidly adapting, and has nerve endings attached to the base of hair.
- Meissner's corpuscles detect movement of objects over the skin (texture), low-frequency vibration, and have encapsulated dendrites.
- They are found in non-hairy skin (glabrous skin) and are fast adapting.
Adaptation and Mechanisms
- Chemoreceptors and pain receptors do not adapt to maintain sensitivity to important stimuli.
- Mechanisms of adaptation include:
- Receptor structure adjustment
- Nerve fiber sodium channels deactivation
- Central or signal from CNS to shut down receptor or adjust receptor structure
- Adaptation can occur at receptor level, spinal cord level, or cortical level.
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Description
This quiz covers the concepts of tactile sensation, pressure, vibration, and touch, including the detection of these sensations by the body. Learn about the different types of receptors and their roles in perceiving these sensations.
