Chapter 11, Muscular System Flashcards
Types of muscles
Parallel: biceps brachii
Convergent: pectoralis major, rectus abdominous, supinator
Pennare: rectus femoris, deltoid,
Circular: orbicularis oris
Parallel muscles
Fascicles are parallel to the long axis
Convergent muscles
Fascicles extent over a large surface area and converge at a common attachment point. Muscle fibers pull in different directions rather than one in parallel.
Pennate muscles
Form a common angle with their tendon and contract at an angle. Do not move their tendon as much as parallel muscles. Produce more tension because they contain more muscle fibers.
Unipennate
Bipennate
Multipennate
Circular muscles
Circularly located around an opening, also called sphincters and guard body openings
Purpose of a lever
Attaching to a muscle a lever can modify force, speed, or direction of movement.
A lever is a ridged structure such as bone-that moves on a fixed fulcrum
3 important things about levers
They can change:
- direction of an applied force
- distance and speed of movement produced by an applied force
- effective strength of applied force
First class lever
Pry bar
Fulcrum lies between the applied force and the load
Example: neck
Origin
Fixed attachment to a bone, cartilage or connective tissue
Insertion
The site where the movable end attaches to another structure
Ways to define muscles based on their functions
Agonist
Antagonist
Synergist
Fixator
Agonist
Prime mover, a muscle whose contraction is mostly responsible for producing a movement
Antagonist
A muscle whose action opposes the action of an agonist
Synergist
Contracts to help a larger agonist work efficiently
Fixator
A synergist that assists an agonist by preventing movement at another joint, thereby stabilizing the origin of the agonist
Descriptive terms used to name skeletal muscle
Location in the body Origin and insertion Fascicle organization Posisiton Structural characteristics Action
Muscles of the axial
Head and neck
Vertebral column
Oblique and rectus muscles
Pelvic floor
Second class lever
The load lies between the applied force and the fulcrum, wheelbarrow
Body example Heel lift
Third class lever
The applied force is between the load and the fulcrum, catapult
Biceps curl
Muscles of the mouth in facial expression
Buccinator: compresses cheeks
Depressor libii inferiois: depresses lower lip
Levator libii superiois: elevates upper lip
Levator anguli oris: smile muscle
Mentalis: elevated and prodrudes lowe lip ( pout muscle)
Orbicularis oris: compresses purses lips
Risorius: draws corner of the mouth to the side
Depressor anguli oris: depresses corner of the mouth
Zygomatic major: retracts and elevates corner if the mouth
Zygomatic minor: retracts and elevates upper lip
Muscles of the eye in facial expression
Corruegator supercilii: wrinkles eye brow
Levator papebrae superioris: elevates upper eye lid
Orbicularis oculi:closes eyes
Muscles of the nose in facial expression
Procerus: moves nose and changes position and shape of the nostrils
Nasalis: Compresses bridge, depresses tip of nose and elevates corners of nostrils
Muscle of the ear in facial expression
Temporoparietalis: tenses scalp, moves auricle of ear
Muscles of scalp in facial expression
Occipitofrontalis: raises eyebrows wrinkles forehead
Occipital belly: tenses and retracts scalp
