36 Questions
What is the primary function of tendons?
To connect bone to muscle and transmit force from muscle to bone
Which of the following is NOT a component of the structure of tendons?
Bone cells
Which of the following mechanical properties of tendons is MOST important for their function?
Tensile strength
What is the primary effect of stress deprivation on the mechanical properties of tendons?
Decreased tensile strength
Which of the following is a key biological factor that affects the mechanical behavior of tendons?
Cellular metabolism
During the healing process of a tendon injury, which mechanical property INITIALLY decreases the most?
Tensile strength
What is the function of the paratenon surrounding tendons?
Reduces friction between tendons and surrounding tissue
What fills the space between the parietal and visceral membrane in synovial sheaths?
Synovial (peritendinous) fluid
What type of collagen is present in the paratenon?
Type III collagen
Where is the epitenon located in relation to the paratenon?
Below the paratenon
What angle do the Epitenon fibers form with the tendon axis initially?
60°
Which structure adds a mechanical advantage to flexion under the annular pulleys?
Parietal sheet
What is the primary function of the musculotendinous unit?
To transmit tensile forces created in the muscle to the bone
What is the key compositional difference between tendons and ligaments?
Tendons transmit tensile forces from muscle to bone, while ligaments limit joint motion between bones
What is the primary function of the tendon synovial sheath?
To allow the tendon to glide smoothly on the bone surface
How do the general biomechanical behaviors of tendons and ligaments differ?
Tendons can withstand unidirectional tensile loads, while ligaments can resist high tensile loads in one direction and smaller tensile loads in other directions
What is the function of the myotendinous junction (MTJ) and the osteotendinous junction (OTJ) within the musculotendinous unit?
The MTJ connects the muscle to the tendon, while the OTJ connects the tendon to the bone
What is the primary role of the tenocytes and tenoblasts within the musculotendinous unit?
To synthesize collagen and elastin for the tendon
What is the primary role of the tenocytes within tendons?
Synthesizing and maintaining the collagen fibers
Which of the following is NOT a factor that affects the mechanical behavior of tendons?
Presence of muscle spindles
During the healing process of a tendon injury, which mechanical property is LEAST affected initially?
Stress relaxation
What is the primary function of the synovial sheath surrounding tendons?
Reducing friction and facilitating gliding motion
Which of the following is a key biological factor that affects the mechanical behavior of tendons during aging?
Increased collagen cross-linking
What is the primary function of the musculotendinous unit?
Transmitting muscle force to bone for movement
Which of the following statements about the musculotendinous unit is NOT true?
It is synthesized by myocytes and myoblasts.
What is the primary function of the tendon synovial sheath?
To facilitate gliding of tendons over bony surfaces.
Which of the following statements best describes the biomechanical behavior of tendons?
Tendons withstand unidirectional tensile loads.
Which of the following statements about the composition of tendons and ligaments is true?
Tendons have a higher concentration of collagen compared to ligaments.
What is the function of the myotendinous junction (MTJ) and the osteotendinous junction (OTJ) within the musculotendinous unit?
The MTJ connects the muscle to the tendon, while the OTJ connects the tendon to the bone.
What is the primary function of the paratenon surrounding tendons?
To provide a vascular supply and a source of cells for tendon repair.
What is the primary function of the synovial (peritendinous) fluid found in the space between the parietal and visceral membranes of synovial sheaths?
To facilitate smooth gliding and nutrition of tendons
Which of the following statements accurately describes the function of the paratenon surrounding some tendons?
It acts as an elastic sleeve to reduce friction during tendon movement
What is the primary function of the epitenon surrounding the tendon fibrillar network?
To allow for slight reorientation of collagen fibers during tendon stretching
How do the Epitenon fibers reorient themselves when the tendon is stretched?
They decrease their angle from 60° to 30° relative to the tendon axis
Under the annular pulleys, which structure adds a mechanical advantage to flexion?
The synovial sheath
What is the primary function of the synovial cells present in the parietal sheet of synovial sheaths?
To secrete synovial fluid for lubrication
Study Notes
Tissue Mechanics IV: Ligament/Tendon Structure and Metabolism
- Tendons transmit tensile forces created in the muscle to the bone
- Composed of collagen and elastin embedded in a matrix of proteoglycan and water
- Synthesized by tenocytes and tenoblasts
- Proximal attachment: each muscle has proximal and distal tendon
- Distal attachment: myotendinous junction (tendon-muscle) and osteotendinous junction (tendon-bone)
Tendon vs. Ligament: Composition
- Tendons: muscle to bone, transmit tensile forces
- Ligaments: bone to bone, limits joint motion
- Compositional differences between tendons and ligaments
Tendon Micro-architecture
- Tendons withstand unidirectional tensile loads
- Ligaments resist high tensile loads in one direction and smaller tensile loads in other directions
Tendon and Surrounding Structures
- Tendon synovial sheaths: closed duct around tendons gliding on bone surfaces
- Synovial sheaths composed of two membranes: inner (visceral) and outer (parietal) sheets
- Space between parietal and visceral membrane filled with synovial (peritendinous) fluid
- Facilitates smooth gliding of tendons and aids in nutrition
- Under annular pulleys, adding a mechanical advantage to flexion
Paratenon and Epitenon
- Paratenon (peritendinous sheet): reduces friction in tendons without synovial sheath
- Composed of loose fibrillar tissue (type I and III collagen)
- Functions as an elastic sleeve permitting free movement of tendon against surrounding tissue
- Inner surface has synovial cells
- Epitenon: located under paratenon, surrounds tendon fibrillar network of collagen
- Strands run oblique, longitudinal, or transverse to the long axis of the tendon
- Epitenon fibers at 60° to the tendon axis, reorient to 30° after stretching (angle decreases)
Objectives
- Describe the components and organization of dense regular connective tissues (tendons and ligaments)
- Describe the mechanical behavior of tendons and ligaments in response to tensile loads
- Describe physical and biological factors affecting the mechanical behavior of tendons and ligaments
- Discuss the response of tendons and ligaments to stress deprivation and remobilization
- Describe the mechanical properties of tendons and ligaments during healing
Explore the construction, structure, and metabolism of tendons, focusing on collagen fibers, cells, and biomechanical properties. Optional reading on functional outcomes of acute Achilles tendon rupture with and without operative treatment.
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