Chapter 11 - Muscles of the Body Flashcards
Rigor Mortis
Affects skeletal muscle tissue several hours after death
Depletion of ATP in muscle fibers causes stiffness of joints
Crossbridges are stuck in bound position because there is no ATP to release them
Leverage
Use of a lever to move an object
Lever
Rigid bar that moves on a fixed point which is called a fulcrum
Allow more effort to be applied to a given load (or allow load to be moved farther)
Load
Object being moved
Effort
Force to move load
Mechanical Disadvantage
Load is farther from fulcrum than effort
Mechanical Advantage
Load is close to fulcrum and effort is far from fulcrum
Law of levers
When effort is farther from fulcrum than the load, then advantage; when effort is nearer than the load, then disadvantage
First Class Lever
Effort is applied at one end, and the load is at the other end
Fulcrum is somewhere in the middle
Second Class Lever
Effort is applied at one end, and fulcrum is at the other
Load is in between
Third Class Lever
Effort is applied between the load and the fulcrum
Fascicle
Bundle of muscle fibers
Fascicle Arrangement
4 different patterns: parallel, convergent, pennate, circular
Parallel Fascicle Arrangement
Axes of fascicles run parallel to muscle itself
Convergent Fascicle Arrangement
Muscle origin is broad, and fascicles converge toward a tendon of insertion
Pennate Fascicle Arrangement
Fascicles are short and attach obliquely to tendon that runs entire length of muscle
Unipennate
Fascicles insert into one side of tendon
Bipennate
Fascicles insert into both sides of tendon
Multipennate
Several “feathers” present
Circular Fascicle Arrangement
Fascicles arranged in concentric rings
Agonist
Prime mover
Sometimes 2 muscles work together, both as agonists
Antagonist
Opposes or reverses the movement of the agonist
Synergist
Helps agonist by either providing additional force or by eliminating extra movements