Classification of Sensory Receptors

Study Notes

Classification of Sensory Receptors

Sensory receptors can be classified based on their location, the stimulus they detect, and their structure.

Types of Receptors by Location

Exteroceptors: Located on or near the body's surface, these receptors detect external stimuli such as pressure, temperature, touch, and pain.
Visceroceptors: Found within the organs, these receptors respond to various stimuli indicating internal conditions (e.g., hunger, thirst).
Interoceptors: Another term for visceroceptors, indicating their role in sensing internal organ conditions.
Proprioceptors: Specialized visceroceptors found in skeletal muscles, joint capsules, and tendons, providing body orientation and positional information.

Types of Receptors by Stimulus Detected

Mechanoreceptors: Activated by mechanical changes such as pressure applied to the skin.
Chemoreceptors: Respond to changes in chemical concentrations, such as those involved in taste, smell, and monitoring pH and blood glucose levels.
Thermoreceptors: Sensitive to temperature changes.
Nociceptors: Triggered by intense stimuli that cause tissue damage, resulting in the sensation of pain.
Photoreceptors: Respond to light stimuli.

Structural Classification of Receptors

Receptors can be anatomically categorized as either free nerve endings or encapsulated nerve endings.

Free Nerve Endings

The simplest and most common type of receptor, widely distributed throughout the body.
Often associated with pain sensations.

Specialized Free Nerve Endings

Merkel Disks: Detect sensations of light touch through free nerve endings.
Root Hair Plexuses: Located around hair follicles, these receptors detect hair movement.

Encapsulated Nerve Endings

Characterized by a connective tissue capsule surrounding the dendritic end of the receptor.

Types of Encapsulated Nerve Endings

Pacinian Corpuscle: Found deep in the dermis, these receptors are responsible for sensing deep pressure.
Meissner's Corpuscle: Sensitive to light pressure, located in the dermal papillae.
Ruffini's Corpuscle: Senses hot temperatures and persistent touch, helping in prolonged grasp of objects, like steering wheels.
Krause's End Bulb: Located in mucous membranes, these receptors detect touch and cold temperature.

Stretch Receptors

Muscle Spindles: Present in skeletal muscles, they detect muscle length and stretch.
Golgi Tendon Organs: Located at musclotendinous junctions, these receptors prevent muscle tearing by detecting muscle tension.

Description

Explore the different types of sensory receptors through flashcards that define key classifications. This quiz covers exteroceptors and visceroceptors, highlighting their locations and the stimuli they detect. Test your understanding of sensory receptor classification!