Sensory nerve endings Flashcards
Describe the structure and function of free nerve endings (sensory modalities).
They are formed by branching terminations of sensory fibres in the skin. They are widespread but are mainly in epithelia and connective tissues. Their sensory modalities are detecting pain, heat and cold.
Describe the structure and function of golgi tendon organs (sensory modalities).
They are tree-like sensory endings enclosed in a spindle-like connective tissue capsule. They lie within tendons near muscles. Their sensory modality is detecting tension on tendons/proprioception.
Describe the structure and function of muscle spindles (sensory modalities).
They consist of several differentiated muscle fibres (intrafusal fibres) that are enclosed in a spindle-shaped connective tissue sac. They are within skeletal muscles near tendons. Their sensory modality is detecting stretching of muscles/proprioception.
Describe the structure and function of Pacinian (lamellated) corpuscles (sensory modalities).
They are onion-shaped structures of non-neural (connective) tissue built up around the nerve ending. They are mainly located in subcutaneous tissue, joint capsules, breasts, and genitals. Their sensory modalities are detecting vibration and deep pressure/proprioception.
Describe the structure and function of Meissner’s (tactile) corpuscles (sensory modalities).
They are encapsulated myelinated nerve endings, surrounded by Schwann cells. They can be found in eyelids, tongue, lips, nipples and genitals. Their sensory modalities are detecting light touch and texture.
Describe the structure and function of Ruffini corpuscles (sensory modalities).
They are two to four branched cylindrical segments within a network of fascicles of collagen fibres. They lie within dermis, subcutaneous tissue and joint capsules. Their sensory modalities are detecting heavy touch, pressure, stretching of skin and joint movements.
Describe the structure and function of kinaesthetic joint receptors (sensory modalities).
Banana-like shape. They are within joints, muscles and ligaments around the body. Their sensory modalities are detecting the position and movement of muscles and joints.
Describe the structure and function of Merkel cells (tactile discs) (sensory modalities).
They are oval-shaped, and their membrane interacts with nerve endings in the skin with synapse-like structures. They are within the stratum basale of epidermis (top layer of skin). Their sensory modalities are detecting light touch, texture, edges and shapes.
Describe the structure and function of hair receptors (hair cell plexus) (sensory modalities).
They support cells and hair cells are linked by tight junctions at the apical side of the epithelium. They are located around hair follicles. Their sensory modality is detecting movement of the hairs which contributes to the movement of the head.
Describe the structure and function of Krause end bulbs (sensory modalities).
They are cylindrical or oval bodies consisting of a capsule. They lie within mucous membranes in the eyelids, lips, tongue and more. Their sensory modalities are detecting light touch and texture.
