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Encyclopedia > Golgi organ
Organ of Golgi (neurotendinous spindle) from the human tendo calcaneus.
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Organ of Golgi (neurotendinous spindle) from the human tendo calcaneus.

The Golgi organ, also called Golgi tendon organ, or neurotendinous spindle, is a proprioceptive sensory receptor organ that is located at the insertion of skeletal muscle fibres into the tendons of skeletal muscle. Proprioception (from Latin proprius, meaning ones own) is the sense of the position of parts of the body, relative to other neighbouring parts of the body. ... In a sensory system, a sensory receptor is a structure that recognizes a stimulus in the internal or external environment of an organism. ... A top-down view of skeletal muscle A muscle fiber (American usage) or muscle fibre (British usage) (also technically known as a myocyte) is a single cell of a muscle. ... A tendon (or sinew) is a tough band of fibrous connective tissue that connects muscle to bone. ... A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ...


Anatomy

The body of the organ is made up of strands of collagen that are connected at one end to the muscle fibres and at the other merge into the tendon proper. Each tendon organ is innervated by a single type Ib sensory afferent axon that branches and terminates as spiral endings around the collagen strands. The Ib afferent axon is a large diameter, myelinated axon. Each neurotendinous spindles is enclosed in a fibrous capsule which contains a number of enlarged tendon fasciculi (intrafusal fasciculi). One or more nerve fibers perforate the side of the capsule and lose their medullary sheaths; the axis-cylinders subdivide and end between the tendon fibers in irregular disks or varicosities (see figure). Tropocollagen triple helix. ... In neuroscience, myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. ...


Function

During muscle contraction the strands of collagen are stretched as the muscle shortens. This stretching deforms the terminals of the Ib afferent axon, opening stretch-sensitive cation channels. As a result, the axon is depolarized and fires nerve impulses up to the central nervous system via the spinal cord. The action potential frequency signals the force being developed within the muscle. A cation is an ion with positive charge. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... A diagram showing the CNS: 1. ... Cross-section through cervical spinal cord. ... In physics, a force is an external cause responsible for any change of a physical system. ...


This sensory feedback plays an important role in spinal reflexes and in the central control of muscle contraction. Specifically, it is postulated that because a Golgi tendon organ exists in serial connection with muscle fibers, it can measure the tension that each muscle contraction builds up. The Ib afferent axon synapses with interneurons within the spinal cord and also relays information to the brain. One of the main spinal reflexes receiving an input from the Ib afferent is the autogenic inhibition reflex, which is involved with the regulation of the force profile of on-going muscle contractions. Feedback is (generally) information about actions. ... Illustration of the major elements in a prototypical synapse. ...


The ascending pathways to the cerebellum are the dorsal and ventral spinocerebellar tracts and are involved in the cerebellar regulation of movement. Figure 1a: A human brain, with the cerebellum in purple. ... The spinocerebellar tract is a set of axonal fibers originating in the spinal cord and terminating in the cerebellum. ... Look up movement in Wiktionary, the free dictionary The term Movement has a variety of different meanings related to motion: Physical movement between points in space (A to B). The amount of movement is called distance. ...


Source

This article incorporates text or images from the public domain Gray's Anatomy, Lea & Febiger, 1917 edition. The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... Henry Grays Anatomy of the Human Body, commonly known as Grays Anatomy, is an anatomy textbook widely regarded as a classic work on human anatomy. ...

Nervous system - Sensory system - Somatosensory system - edit
Spinal pathway: Somatosensory information
Medial lemniscusTouch (Pressure & Vibration) | Proprioception
Spinothalamic tractPain | Temperature
Receptors
Touch: Pacinian corpuscles | Meissner's corpuscles | Merkel's discs | Ruffini endings | Free nerve endings | Hair follicle receptors
Proprioception: Golgi organ | Muscle spindle (Intrafusal muscle fiber)
Pain: Nociceptors    Temperature: Thermoreceptors

 
 

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