Search results
Results from the WOW.Com Content Network
A muscle spindle, with γ motor and Ia sensory fibers. A type Ia sensory fiber, or a primary afferent fiber, is a type of afferent nerve fiber. [1] It is the sensory fiber of a stretch receptor called the muscle spindle found in muscles, which constantly monitors the rate at which a muscle stretch changes.
When a muscle is stretched, primary type Ia sensory fibers of the muscle spindle respond to both changes in muscle length and velocity and transmit this activity to the spinal cord in the form of changes in the rate of action potentials. Likewise, secondary type II sensory fibers respond to muscle length changes (but with a smaller velocity ...
This can be part of a withdrawal reflex—initiated by the Aδ fibers in the reflex arc of activating withdrawal responses. [ 7 ] [ 8 ] These are the type III group. Aδ fibers carry cold, pressure, and acute pain signals; because they are thin (2–5 μm in diameter) and myelinated , they send impulses faster than unmyelinated C fibers , but ...
Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors). [ 1 ] [ 2 ] They detect the amount and rate of change in length of a muscle . [ 1 ] They constitute the muscle spindle , [ 2 ] and are innervated by both sensory (afferent) and motor (efferent) fibers.
The typical innervation to muscle spindles consists of one type Ia fiber and 2 type II fibers. [6] The type Ia fiber has "annulospiral" endings around the middle parts of the intrafusal fibers compared to type II fibers that have "flower spray" endings which may be spray shaped or annular, spreading in narrow bands on both sides of the chain or ...
The Golgi tendon organ (GTO) (also called Golgi organ, tendon organ, neurotendinous organ or neurotendinous spindle) is a proprioceptor – a type of sensory receptor that senses changes in muscle tension. It lies at the interface between a muscle and its tendon known as the musculotendinous junction also known as the myotendinous junction. [1]
The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve exits the intervertebral foramen, it branches into the dorsal ramus, the ventral ramus, and the ramus communicans. Each of these three structures carries both sensory and motor information.
With the exception of lower muscles of facial expression, all functions of the corticobulbar tract involve inputs from both sides of the brain. [5] The extrapyramidal system refers to tracts within the spinal cord involved in involuntary movement but not part of the pyramidal tracts. [2] Their functions include the control of posture and muscle ...