The main difference between the muscle spindle and the Golgi tendon organ is that the muscle spindle is a stretch receptor that detects the changes in the length of the muscle, whereas the Golgi tendon organ is a proprioceptor that detects the change in muscle tension.
The muscle spindle and Golgi tendon organ are two receptors influencing the movement. They function to regulate the stiffness of muscles.
Key Areas Covered
1. What is Muscle Spindle
– Definition, Structure, Function
2. What is Golgi Tendon Organ
– Definition, Structure, Function
3. Similarities Between Muscle Spindle and Golgi Tendon Organ
– Outline of Common Features
4. Difference Between Muscle Spindle and Golgi Tendon Organ
– Comparison of Key Differences
Key Terms
Golgi Tendon Organ, Muscle Spindle
What is Muscle Spindle
The muscle spindle is a stretch receptor that occurs in the skeletal muscles. The primary function of the muscle spindle is to detect the changes in the length of the muscle. It transfers information about the length of the muscle fiber to the central nervous system through the afferent nerve fibers. The brain process this information as proprioception. Changing the muscle fibers’ length is important for muscle contraction.
Figure 1: Muscle Spindle Model
Furthermore, the muscle spindle occurs inside the belly of the skeletal muscle. It is spindle-shaped. Also, it is made up of special fibers known as intrafusal muscle fibers. Extrafusal muscle fibers are the regular muscle fibers that occur outside the spindle. Additionally, the muscle spindle has a connective tissue capsule that runs parallel to the extrafusal muscle fibers. A muscle spindle composes of 5-14 muscle fibers. There are three types of muscle fibers: dynamic nuclear bag fibers, nuclear chain fibers, and static nuclear bag fibers.
What is Golgi Tendon Organ
The Golgi tendon organ (GTO) is a proprioceptor, a sensory receptor type that detects changes in muscle tension. It occurs on the surface of the muscle between the muscle and its tendon. Therefore, it occurs between the musculotendinous junction. Another name for this junction is myotendinous junction. Structure-wise, braided strands of collagen make up the body of the GTO. The GTO is encapsulated. The capsule connects to 10-20 fibers. The length of the capsule is 1 mm. Also, the diameter is about 0.1 mm. The afferent supply to the GTO is from type Ib sensory nerve fibers (Aɑ fiber). The Aɑ fibers contain 12-20 μm long, myelinated axons. Afferent nerve fibers do not contain medullary sheaths, branch, and intertwine inside the capsule.
Figure 2: Golgi Tendon Organ Model
Moreover, sensory terminals of the GTO compress when the muscle generates force. It opens the stretch-sensitive cation channels, depolarizing Ib afferent axon. The nerve impulses propagate to the spinal cord.
Similarities Between Muscle Spindle and Golgi Tendon Organ
- The muscle spindle and Golgi tendon organ are two receptors in muscles.
- They regulate the stiffness of muscles.
Difference Between Muscle Spindle and Golgi Tendon Organ
Definition
The muscle spindle refers to a stretch receptor that signals the length and changes in the length of muscles, while the Golgi tendon organ refers to a proprioceptor that receives information from the tendon that senses tension.
Type of Receptor
The muscle spindle receptor is a stretch receptor, while the Golgi tendon organ is a proprioceptor.
Structure
The muscle spindle has connective tissue surrounding intrafusal fibers in a capsular structure, while the Golgi tendon organ has a tree-like sensory ending enclosed in a spindle-like connective tissue capsule.
Afferent Axon
The muscle spindle contains Ia sensory fibers, while the Golgi tendon organ contains Ib sensory fibers.
Function
The muscle spindle receptor detects the changes in the length of the muscle, while the Golgi tendon organ detects the changes in the muscle tension.
Conclusion
In brief, the muscle spindle and Golgi tendon organ are two receptors that occur in muscles. They are important for the regulation of the stiffness of muscles. The muscle spindle receptor is a stretch receptor. It has connective tissue surrounding intrafusal fibers in a capsular structure. Also, it detects changes in the length of the muscle. In comparison, the Golgi tendon organ is a proprioceptor. It has a tree-like sensory ending enclosed in a spindle-like connective tissue capsule. However, it detects changes in muscle tension. Therefore, their function is the main difference between the muscle spindle and the Golgi tendon organ.
References:
- Wikimedia Foundation. (2021a, May 28). Muscle Spindle. Wikipedia. https://en.wikipedia.org/wiki/Muscle_spindle
- Wikimedia Foundation. (2023d, January 29). Golgi tendon organ. Wikipedia. https://en.wikipedia.org/wiki/Golgi_tendon_organ
Image Courtesy:
- “Muscle spindle model” By Neuromechanics – Own work (Public Domain) via Commons Wikimedia
- “Tendon organ model” By Neuromechanics. – Own Work (Public Domain) via Commons Wikimedia
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