Week 6 - Skeletal Muscle Tissue Flashcards
What structures do collagen fibres of muscle fascicles merge into?
Tendons or aponeuroses
Where do tendons attach muscles?
To specific points on bone
What is the function of an aponeurosis? and give example of where it’s located
Provides attachment over a large area, such as skull and abdomen
How do some muscles attach directly to bone?
By their epimysium fusing to periosteum
What are muscle fibres in a single fascicle called?
Fascicles
How does the organization of fascicles in relation to the muscle tendon vary?
It varies based on the amount of power and range of motion a muscle can produce
What are the four major arrangements of muscles based on fascicular organization?
Parallel, pennate, convergent and circular
Describe parallel muscles.
Their fascicles run parallel to the long axis, all in the same direction, and they have a large range of motion.
What is the characteristic feature of pennate muscles?
Their fibres run at an oblique angle to tendon insertion.
Give an example of a unipennate muscle.
Extensor digitorum (forearm)
What is the function of multipennate muscles? and give an example
They allow for a high degree of power generation due to the arrangement of their fibres. Deltoid muscle
Explain the structure of convergent muscles.
Fascicles extend over a broad area and converge on a common attachment site.
What type of muscle is a sphincter?
A circular muscle
What is the function of circular muscles?
Serves as a sphincter around an opening
How do muscles move bones in the body?
By applying force to pull bones via joints, acting as levers
What determines the force, speed, and direction of muscle contraction?
The nature and site of muscle attachment
What is the relationship between force and distance in levers?
Force × distance = resistance × distance
How do levers change the direction of an applied force?
By altering the position of the fulcrum relative to the load and effort
Explain the concept of mechanical advantage in levers.
It allows a small force to move a large load over a short distance.
Explain the concept of mechanical disadvantage in levers.
It allows a big force to move a light load over a long distance
Give an example of a first-class lever in the body.
The flexion/extension of the neck at the atlanto-occipital joint
Describe the characteristics of a second-class lever.
The force is further away from the fulcrum than the load, providing a mechanical advantage.
What is the main function of third-class levers?
They allow small loads to be moved long distances at fast speeds, working at a mechanical disadvantage.
Why is it easier to lift lighter weights than heavier ones?
Because speed is inversely related to load, and it takes longer for movements to begin with heavier weights.
What is the optimal combination of tension and speed for a given load in muscles?
Each muscle has an optimal combination of tension and speed for a given load.
What is the function of muscles in relation to joints?
All muscles cross at least one joint and produce movement when contracted.
What are the two attachments of muscles?
Origin (proximal) and Insertion (distal)
How do muscles work in pairs or groups?
One muscle acts as the prime mover (agonist), while the other acts as the antagonist, relaxing when the agonist contracts.
What is the function of synergist muscles?
They assist the prime mover, making its action more efficient.
