Muscles Flashcards
What are the three types of muscle and examples
Skeletal Muscle - bicep and tricep
Smooth Muscle - intestines
Cardiac Muscle - heart
what are the two types of muscle fiber arrangements
Fast Twitch - contract quickly, providing short burst of power
Slow Twitch - contract gradually, little power but resistance to fatigue
what is meant by contraction, extensibility and elasticity
contraction - muscles shorten when they contract
extensibility - muscles can be stretched
elasticity - muscles return to their original length after being stretched
what are the levels of the structure of skeletal muscle
- skeletal muscle
- bundles of muscle fibres
- myofibrils
- myofilaments
- actin and myosin
Explain the first level of the structure
connective tissue encases bundles of muscle cells (allowing bundles to slide over each other in contraction) and joins at the end of muscles to form tendons (attaching to bone)
Explain the second level of the structure
Muscle fibers are long cylinders with many nuclei lying parallel to each other (vary in length)
Explain the third level of the structure
Myo fibrils which can be divided into sarcomere units (Z lines capacity) are surrounded by plasma membrane and contain cytoplasm, regulates calcium ions in muscle cells
Explain the forth level of the structure
myofilaments are proteins slide past each other during muscle contraction (made up of two smaller structure)
Explain the fifth level of the structure
thin myofilament - actin (straight line)
thick myofilament - myosin (squigly line)
overlap to shorten overall unit
what happens when muscle relaxes
sarcomere lengthens ( Z and I lines further)
what happens when muscle contracts
sarcomer shortens ( Z and I closer)
explain the 5 types of movements
Flexion - decreases the angle between the bones of the joint bringing the bones closer together (butt kick)
extension - increase the angle between the bones of the joint (leg raise)
adduction - body part toward midline (leg side lift in)
abduction - body part away from midline (leg side lift out)
rotation - body part around its own axis (turn head)
what is an antagonistic pair
pairs of muscles working together to move bones in opposite direction
what is an agonist w example
the contraction of muscle that causes the desired action (moving elbow - bicep)
what is an antagonist w example
the relaxing of muscle that moves the limb as the effect of the desired action (moving elbow - tricep)