U3 Lecture 18 Flashcards
- list and describe the specific functions of skeletal muscle - define the terms origin and insertion and describe the action and the reverse action of a muscle using these terms - list and describe the three classes of levers, giving examples of each - describe the classification of muscles base on action, and be able to determine the role played by a muscle in a particular movement
What are the three types of muscle?
Skeletal, cardiac, and smooth
What is the basic function of all three types of muscle?
Generate tension
Functions of skeletal muscle
- Locomotion
- Facial expression
- Posture and body position
- Regulation of body temperature
Is skeletal muscle voluntary or involuntary?
Voluntary
Characteristics of skeletal muscle
- Always requires nervous system input
- Can be automatic, but we have the ability to change skeletal muscle activity
(ex: contraction of diaphragm- breath differently)
Define origin
Where the muscle starts on a bone (stays stationary)
Define insertion
Where the muscle attaches to (moves towards origin)
Muscles do what on bone?
Muscles pull on bone
What are the two types of body movement?
Flexion and extension
and
Abduction and Adduction
What movement is the body in during the standard anatomical position?
Everything is extended except for foot
What is flexion?
Bending or moving the body in a position with a reduced angle
What is extension?
Increased angle of body positions
Examples of flexion and extension
Elbow joint, knee joint, hip joint, shoulder joint
Define Abduction
movement away the midline of body
Define adduction
movement toward the midline
Examples of abduction and adduction
arm and thigh
Reverse muscle action (RMA)
When the insertion is anchored, the origin moves towards the insertion
Ex: pull ups
How to classify a muscle based on action
action, muscle group, origin, and insertion
Define agonist
muscle primarily responsible for the movement
Define antagonist
muscle which opposes the action of the agonist
Define synergist
assists the agonist in making the action more efficient
Define fixator
special synergists which help to prevent movement at muscle origin
Flexion of forearm classifications
Agonist- brachialis
antagonist - triceps brachii
synergist- biceps brachii
fixator- pectorlis minor
Abduction of the arm classifications
agonist - deltoid
antagonist- latissimus dorsi
synergist - supraspinatus
fixator - trapezius
Define lever
Ridge bar -> bone
Define fulcrum
Fixed point around which the ridge bar (bone) moves -> joint
How do muscles move?
Muscles act to facilitate movement at a fulcrum (joint) by exerting force on the lever (bone)
Types of lever systems
1st class
2nd class
3rd class
1st class levers
Fulcrum in the middle, effort on one end and load on the other
2nd class levers
Fulcrum on one end and effort on another. Load is in the middle
3rd class levers
Fulcrum on one end and load on the other. Effort is in the middle
Which lever is a balanced lever system?
1st Class Levers
Which lever sacrifices speed and range of motion for force?
2nd class levers
Which lever favors speed and range of motion over force
3rd class levers
Which level is the most common type in the human body
Third class levers
