Chapter 10 Study Guide
Name and identify the major muscles of the human body. State the origin, insertion, and action of each muscle.
...
Names the three types of lever systems and indicate the arrangement of effort, fulcrum, and load in each. Also note the advantages of each type of lever system.
First-class lever: (scissors) Load Effort Fulcrum Mechanical advantage (strength) or mechanical disadvantage (speed and distance) Second-class lever: (wheelbarrow) Load Fulcrum Effort Strength Third-class lever: (tweezers) Load Effort Fulcrum Speed
Explain how a muscle's position relative to a joint affects its action.
A muscle that crosses on the anterior side of a joint produces flexion. A muscle that crosses on the posterior side of a joint produces extension. A muscle that crosses on the lateral side of a joint produces abduction. A muscle that crosses on the medial side of a joint produces adduction.
List the criteria used in naming muscles. Provide an example to illustrate the use of each criterion.
Muscle location: ex. temporalis overlies the temporal bone Muscle shape: ex. deltoid is roughly triangular Muscle size: ex. gluteus maximus vs. gluteus minimus Direction of muscle fibers: ex. transversus abdominis runs transverse in the abdomen Number of origins: ex. biceps brachii has two origins Location of the attachments: ex. sternocleidomastoid has a dual origin on the sternum and clavicle and inserts on the mastoid process Muscle action: ex. adductor longus
Describe the functions of prime movers, antagonists, synergists, and fixators.
Prime mover: a muscle that has the major responsibility for producing a specific movement. Antagonist: muscles that oppose, or reverse, a particular movement. Synergist: helps prime movers by adding a little extra force to the same movement or by reducing undesirable or unnecessary movements. Fixator: when a synergist immobilizes a bone or a muscle's origin so that the prime mover has a stable base on which to act.
Define lever.
a rigid bar that moves on a fixed point called a fulcrum when a force is applied to it.
