Download Muscles and Muscle Tissue

Lever Systems: Bone-Muscle
Relationships
Bone-Muscle Relationships: Lever
Systems
Lever- rigid bar; free to turn about fixed point ex.
bone
a. Fulcrum- fixed point; ^
ex. joint
b. Load- resistance moved; L
ex. part of body
c. Force- pull from contraction; F
ex. muscle
Bone-Muscle Relationships:
Lever Systems
Mechanical advantage
Figure 10.2a
Bone-Muscle Relationships:
Lever Systems
Mechanical disadvantage
Figure 10.2b
Lever Relationships
• Effort farther than load from fulcrum equals
mechanical advantage
• Effort nearer than load to fulcrum equals
mechanical disadvantage
Lever Systems: Classes
a. 1st Class- Fulcrum between Load & Force; seesaw;
stability
Ex. Head tilt
b. 2nd Class- Load between Fulcrum & Force; wheelbarrow; lift
Ex. Raising body with toes
c. 3rd Class- Force between Fulcrum & Load; shovel; rapid mov’t
Ex. Flex forearm
Lever Systems: Classes
Figure 10.3a
Lever Systems: Classes
Figure 10.3b
Lever Systems: Classes
Figure 10.3c
In this example the weight is
situated between the force and
the fulcrum
In this example the force is
located between the weight
and the fulcrum
In this case the fulcrum is located
between the force and weight
Machines of the Body
Prime movers and synergist muscles
Agonist and antagonist muscles
Apart from assisting in locomotion does the muscular system play
any other role?
Posture; this includes the erector spinae muscles and the muscles
of the trunk.
Salient points
• Muscle groups are classified upon the the arrangement of the
muscles fibres, this provides a wide range of muscle types.
• The origin of the muscle is that attachment at which the bone
is stationary
• The insertion of the muscle is at that attachment where the bone is
moving
• Muscle can have several different roles; they can be
agonists, antagonists and synergists
• Not all muscles are involved in locomotion, they also
enable other important bodily functions, for example,
respiration, provide movement for the eye, assist in
swallowing and speech
Major Skeletal Muscles: Anterior
View
• The 40 superficial
muscles here are divided
into 12 regional areas of
the body
Figure 10.4b
Major Skeletal Muscles: Posterior
View
• The 27 superficial
muscles here are divided
into seven regional areas
of the body
Figure 10.5b
Origin
Insertion