SKELETAL MUSCLE: MUSCLE AND TENDON RECEPTORS Flashcards
Muscle fibres may not be ____ in the line of action of force
orientated
Forces occur in all three-dimensions, and are transmitted through _____
connective tissues
Describe the anatomy and general function of tendon
Tendon: highly organized connective tissue joining muscle to bone
- made up of collagen fibres
- flexible so it can bend at joints
- resists high tensile force
- shock absorption
- transmits muscle force to skeleton
- stretches and stores mechanical energy
Define: paratenon
fatty areolar tissue surrounding tendon
Define: tenocytes
tendon cells
Describe the tendon’s ability to conserve energy
Energy conservation: mechanical energy (muscle work) is conserved; energy flows from the body to the tendon and back to the body; seen in running, hopping, walking
Describe the tendon’s ability to amplify power
Power amplification: tendons loaded directly by the work of muscle contraction can amplify muscle power; energy flows from the muscle to the tendon and back to the body
Describe the tendon’s ability to attenuate power
Power attenuation: a rapid decline in mechanical energy can be temporarily stored as elastic strain; energy flows from the body, to the tendon, and then to the muscle.
Differentiate between internal and external tendon
External tendon: extends from the muscle belly
Internal tendon: extends into the muscle belly; typically referred to as aponeurosis
Aponeurosis: a sheet of pearly white fibrous tissue that takes the place of a tendon in flat muscles having a wide area of attachment.
- pennate muscles have 2 aponeurosis; muscle fibres join the two and each thins into small tendon that is attached to bone; stretched by forces of muscle contraction; absorb energy (like a spring) and return it when they recoil
Define the pennation angle in a muscle, and describe how it affects muscle force
Actual force (in line of action) = muscle fibre force x COSINE(pennation angle)
lower the angle, greater the actual force in line of action.
higher the angle, less actual force in line of action
- pennation (short fibres at an angle to the axis of shortening) produces slow shortening but more tension
Describe the influence of tendons on contractile function of muscle
Shortening contractions require myosin heads to be detached more of the time, producing _____ force (right figure)
less
In lengthening contractions, there is no need for myosin heads to detach and re-establish actin-myosin cross bridges (left figure), producing ____ force
greater
Define the PCSA and state how it is useful
PCSA is the physiological cross- sectional area of muscle at given points (usually widest point).
Helpful in estimating (number of sarcomeres in parallel) and force generation.
Explain the anatomy and function of Golgi tendon organs
Golden tendon organ: organ that sits at the intersection of tendon and muscle fibre. Sits in series with the muscle fiber. tells how much tension the muscle is exerting; if there’s too much tension it will inhibit the muscle from creating any force to protect you from injuring yourself.
1 Afferent: IB
