Skeletal muscle Flashcards
What are the different roles of skeletal muscles?
Force generation for movement (of the skeleton)
Force generation for breathing (diaphragm)
Heat movement ( shivering- homeostasis)
Metabolism - a reservoir for amino acids
forms of glucose storage-glucose can be released upon demand
What are the types of muscles found in the human body
Cardiac
Smooth muscles
Skeletal
Describe the structure of skeletal muscle
Striated skeletal muscle Voluntary Controlled by somatic nervous system no branching MULTI NUCLEATED
Describe the structure of cardiac muscle
Striated cardiac muscle Involuntary Controlled by autonomic nervous system branching cells joined by interrelated disk
Describe the structure of smooth muscle
Non-striated cardiac muscle Involuntary Controlled by autonomic nervous system single cells spindle shaped
Describe some of the properties of skeletal muscles
Human muscles fibre= muscle cell
40-100 um in diameter and several cm long
Myonuclei located in the periphery - controls the COMMON cytoplasm- packed with myofibrils and mitochondria.
Describe the role of tendons in muscle contraction
Muscles attach to the skeleton via tendons- which transmits muscles force to the bone- these cause the skeleton to move at the joint.
Tendons are stiff and strong as they are made up of collagen
How do muscles work?
They work by pulling
they work in antagonistic pairs which allows for a range of movements- skeleton can return to original position
Flexor muscle- decreases the angle anteriorly-the muscle that bend the joint
Extensor muscle- increases the angle anteriorly- the muscle that extends the joint
Different movements possible depending on the type of joint and the muscle arrangement
What are the types of muscle contraction?
Isotonic- dynamic
Isometric
Concentric
the muscles shortens when it contracts
Eccentric
the muscle lengthens during force production eg slowly extending muscle after flexion
Isometric
the muscle exerts the force without changing the length
eg moving an immovable object
Prime mover
Agonist- muscle contraction is concentric (bicep)
eg Gravity
Antagonist-
It apposes the action of the prime mover (tricep)
Fixator-
steadies and holds position through isometric contraction