Questions and Answers
What are tonic receptors?
Sensory neurons that are always active.
What are phasic receptors?
Sensory receptors that provide information about the intensity and rate of change of stimulus.
What is adaptation?
A reduction in sensitivity in the presence of a constant stimulus.
What is an example of a fast-adapting receptor?
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What is an example of a slow-adapting receptor?
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What are the four types of sensory receptors?
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Where are nociceptors found?
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What are nociceptors sensitive to?
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What two types of axons carry painful sensations and what types of pain sensations do they carry?
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Are nociceptors tonic or phasic receptors?
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What neurotransmitters are released by the activation of nociceptors?
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What neurotransmitters are released to reduce the sensations of pain?
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Where are thermoreceptors found?
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Are thermoreceptors tonic or phasic receptors?
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What are the three classes of mechanoreceptors?
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What are the six types of tactile receptors?
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What are free nerve endings sensitive to?
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What are root hair plexus sensitive to?
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What are tactile discs sensitive to?
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What are tactile corpuscles sensitive to?
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Where are tactile corpuscles located?
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What are lamellated corpuscles sensitive to?
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Where are lamellated corpuscles found?
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What are Ruffini corpuscles sensitive to?
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Where are Ruffini corpuscles located?
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What can alter our sensitivity to tactile sensations?
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What do baroreceptors monitor?
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What are the three major groups of proprioceptors?
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Chemoreceptors respond to what types of substances?
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Study Notes
Sensory Receptors Overview
- Tonic receptors are sensory neurons that remain continuously active, providing a constant signal.
- Phasic receptors respond to changes in stimuli intensity and rate, allowing the detection of dynamic changes.
Adaptation and Sensitivity
- Adaptation refers to a decrease in sensitivity when exposed to a constant stimulus over time.
- Fast-adapting receptors, like thermoreceptors, quickly adjust to changes in temperature.
- Slow-adapting receptors, such as nociceptors, maintain their response to persistent stimuli.
Types of Sensory Receptors
- Four primary types include nociceptors (pain), thermoreceptors (temperature), mechanoreceptors (pressure), and chemoreceptors (chemical detection).
Nociceptors
- Located in superficial skin, joint capsules, periosteum of bones, and around blood vessel walls.
- Sensitive to extremes of temperature, mechanical injury, and chemical changes.
- Pain sensation is transmitted via Type A axons for fast pain and Type C axons for slow pain.
- Function as tonic receptors, providing continuous pain signals.
- Activation causes the release of neurotransmitters like Substance P and Glutamate; pain modulation involves Endorphins and Enkephalins.
Thermoreceptors
- Found in the dermis, skeletal muscles, liver, and hypothalamus.
- Function as phasic receptors, adapting quickly to changes in temperature.
Mechanoreceptors
- Divided into three classes:
- Tactile receptors (sensitive to touch),
- Baroreceptors (sensitive to pressure changes),
- Proprioceptors (sensitive to body position).
Tactile Receptors
- Six types include:
- Free nerve endings (detect touch and pressure),
- Root hair plexus (sensitive to surface distortions),
- Tactile discs (fine touch and pressure),
- Tactile corpuscles (fine touch, pressure, low-frequency vibrations), found in areas like eyelids, lips, and fingertips,
- Lamellated corpuscles (deep pressure and high-frequency vibrations), located in the dermis and joints,
- Ruffini corpuscles (sensitive to skin pressure and distortion) found in the reticular dermis.
Sensory Modulation
- Sensitivity to tactile sensations can be modified by infections, diseases, or neuronal damage.
- Baroreceptors monitor organ pressure changes, contributing to homeostasis.
- Proprioceptors are classified into muscle spindles, Golgi tendon organs, and receptors in joint capsules, enabling body position awareness.
Chemoreceptors
- Respond to water-soluble and lipid-soluble substances that are dissolved in body fluids, playing a crucial role in chemical sensing.
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Description
Test your knowledge with these flashcards on sensory receptors from Biology Chapter 15. Learn about tonic and phasic receptors, adaptation, and more. Perfect for reviewing key concepts and enhancing your understanding of sensory systems.
