Sensory Receptors

Flashcards about Sensory Receptors, including their function, structure, types, and classifications.

What is the general function of sensory receptors?

To detect and respond to a stimulus and then initiate sensory input to the central nervous system (CNS), which involves converting stimulus energy into an electrical signal.

What are the two features critical to allow sensory receptors to function as transducers?

Sensory receptors establish and maintain a resting membrane potential (RMP) across their plasma membrane, and sensory receptors contain modality-gated channels within their plasma membranes.

What is a modality-gated channel?

A modality-gated channel opens in response to a stimulus other than a neurotransmitter or a voltage change at the plasma membrane.

What is the significance of a receptive field?

The size of the receptive field will determine the ability of the CNS to identify the exact location of a stimulus. A small receptive field provides us with the ability to identify the stimulus location more specifically, while a large receptive field allows us to determine only the general region of the stimulus.

What is a sensation?

A stimulus that we are consciously aware of. A sensation occurs when we recognize a child's face or realize that the room is too warm.

What four characteristics regarding a stimulus is a sensory receptor able to provide the CNS?

Modality, location, intensity, and duration.

How does the CNS determine the intensity of a stimulus?

Because of the change in the number of nerve signals that are arriving along a designated nerve. A greater or more intense stimulus results in the most sensitive sensory receptors initiating nerve signals more frequently and the less sensitive sensory receptors initiating nerve signals.

What is adaptation in the context of sensory receptors?

The decrease in sensitivity to a continuous stimulus as all sensory receptors become less sensitive to a constant stimulus and initiate a progressive decrease in nerve signals.

What is the difference between tonic and phasic receptors?

Tonic receptors demonstrate limited adaptation and continuously generate nerve signals, while phasic receptors exhibit rapid adaptation and generate nerve signals only in response to a new or changing stimulus.

What are the three classifications of sensory receptors based on their distribution?

General senses, Somatic sensory receptors and Visceral sensory receptors

What is the difference between somatic and visceral sensory receptors?

Somatic sensory receptors are located in the skin and mucous membranes and monitor stimuli like texture, pressure, temperature, and pain, while visceral sensory receptors are located in the walls of the viscera and blood vessels and detect stretch, chemical changes, temperature, and pain.

How are exteroceptors, interoceptors, and proprioceptors classified?

Based upon where the stimulus originates. Exteroceptors detect stimuli from the external environment, interoceptors detect stimuli from within our internal environment, and proprioceptors detect body and limb movements.

What are the five groups of sensory receptors based upon their modality of stimulus?

Chemoreceptors, thermoreceptors, photoreceptors, mechanoreceptors, and nociceptors.

What do chemoreceptors detect?

Chemicals, either molecules or ions, which are dissolved in fluid.

What do mechanoreceptors respond to?

Distortion of the plasma membrane that occurs due to touch, pressure, vibration, and stretch.

What is referred pain?

Referred pain occurs when sensory nerve signals from certain viscera are perceived as originating not from the organ, but from somatic sensory receptors within the skin and skeletal muscle.

What is phantom pain?

A sensation associated with a body part that has been removed. Following the amputation of an appendage, a patient often continues to experience pain from what is perceived as the removed part.

Describe tactile receptors.

Tactile receptors are the most numerous type of sensory receptor in the body. They are mechanoreceptors located in the skin and mucous membranes.

List the three types of unencapsulated tactile receptors

Free nerve endings, root hair plexuses, and tactile discs

List the four types of encapsulated tactile receptors

End bulbs, lamellated corpuscles, bulbous corpuscles, and tactile corpuscles.