What are stretch reflexes?
What are stretch reflexes?
Introduction. The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching. When a muscle is stretched, the stretch reflex regulates the length of the muscle automatically by increasing its contractility as long as the stretch is within the physiological limits.
Where does stretch reflex occur?
Anatomy of the Stretch Reflex Located within the belly of the muscle, between and parallel to the main muscle fibers, are muscle spindles. These muscle spindles are made up of spiral threads called intrafusal fibers, and nerve endings, both encased within a connective tissue sheath.
What structure initiates stretch reflexes?
The receptor responsible for initiating a stretch reflex is the muscle spindle. Muscle spindles are found in almost all skeletal muscles and are particularly concentrated in muscles that exert fine motor control (e.g., the small muscles of the hand and eye).
Which reflexes are stretch responses?
The stretch reflex is also referred to as the deep tendon reflex or myotatic reflex. It is a simple pre-programmed response by the human body in response to the muscle being passively stretched e.g. by a tendon hammer, or a sudden change in the ground surface.
Is a stretch reflex a spinal reflex?
Spinal control of the stretch reflex means the signal travels between the muscle and spinal cord. The signal returns to the muscle from the same spinal cord segment as where it entered the spinal cord. This is the shortest distance for a reflex signal to travel, thus creating a fast response.
Which part of the spinal cord is responsible for the integration of the stretch reflex?
lamina IX
The pathway can be described as a ‘reflex arc’ which is made up of 5 components: A receptor – muscle spindle. An afferent fibre – muscle spindle afferent. An integration centre – lamina IX of spinal cord.
Is knee jerk reflex a stretch reflex?
The patellar reflex, also called the knee reflex or knee-jerk, is a stretch reflex which tests the L2, L3, and L4 segments of the spinal cord.
What is the function of stretch receptors?
muscle systems …has important sensory structures called stretch receptors, which monitor the state of the muscle and return the information to the central nervous system. Stretch receptors are sensitive to the velocity of the movement of the muscle and the change in length of the muscle.
Where are stretch receptors located in lungs?
Slowly adapting (pulmonary stretch) receptors (SARs) are mechanoreceptors that lie within the submucosal smooth muscles in the membranous posterior wall of the trachea and central airways (Bartlett et al., 1976). A small proportion of the receptors are located in the extrathoracic upper trachea (Berger, 2000).
Which receptor is associated with detecting stretch?
Stretching of the skin is transduced by stretch receptors known as bulbous corpuscles. Bulbous corpuscles are also known as Ruffini corpuscles, or type II cutaneous mechanoreceptors. Other somatosensory receptors are found in the joints and muscles.