1. Muscles

2. Muscular System
3 types
Visceral (smooth): found inside organs (stomach, intestines, etc.)
Cardiac: found in the heart
Skeletal: attached to our skeleton

3. Skeletal Muscles: Functions
Create voluntary, conscious movement
Maintains posture
Produces heat
Stabilizer of joints

4. Muscle Anatomy Fascia Epimysium Perimysium Fascicle
Bands or sheets of fibrous connective tissue
Fascia surrounds organs, muscles, tissues; looks like a very thin spider web
Epimysium
Surrounds the entire muscle
“epi” means upon or above
Perimysium
Fascia surrounding each fascicle
“peri” means around
Fascicle
Bundle of muscle fibers

5. Muscle Anatomy Myofibril Myofilaments Sarcomere
Thinner fibers within each muscle fiber
Myofilaments
Proteins within each myofibril: actin/myosin
Actin = thin filaments
Myosin = thick filaments
Sarcomere
Groups of myosin and actin
Fundamental subunits of muscle contractions
video

6. Sliding Filament Theory
Actin & myosin slide in and out between each other to form muscle contractions
Z-band: lateral ends of sarcomere

7. Naming Muscles: Characteristics in Muscle Names
Size
Gluteus Maximus/Medius/Minimus
Location/Position
Direction of fibers
Transversus abdominus
Shape
Trapezius
Number of muscle attachments
Biceps Brachii
Action
Adductor Longus
Points of attachment to skeleton

8. The Relationship Bone: lever
Joint
Muscle
The Relationship
Bone: lever
Joint: Fulcrum (a fixed point around which a lever moves)
Muscle: force to move the lever

9. Origin & Insertion Origin of a Muscle Insertion of a Muscle
Attaches to bone that remains stationary during contraction
Gives the muscle something to move against
Attaches to a bone that moves during contraction
A muscles insertion will move towards its origin

10. Antagonist Muscle Pairs
Yin and Yang
Muscle opposites
A balance between opposing forces

11. Antagonist vs. Agonist Elbow flexion: Agonist? Antagonist? Agonist
Prime mover
Mainly responsible for contracting and carrying out a body movement
Allows the movement to happen by relaxing
Performs a movement exactly opposite to that done by the agonist muscle
Elbow flexion:
Agonist?
Antagonist?

12. Helpers Synergists Fixators
Stabilizes a joint where the movement is occurring
This will also help the agonist do it’s job
Stabilizes the origin of the agonist muscle
Stabilizes the joint that the movement moves over
Bicep Curl: rotator cuff muscles are fixators
Mostly found in shoulder & hips

13. Principle of Opposing Muscle Action
“Whenever a particular agonist and its synergist are excited and contract, the antagonist is inhibited and relaxed.”
This occurs all because of the nervous system
Can you contract an agonist and antagonist at the same time?
What would happen?
Body-lock or rigid

14. Muscle Contractions Isometric Isotonic
Contraction with no change in length
Ex: wall sit, plank, etc.
Contraction with muscle shortening and lengthening
Concentric Contraction
Positive contraction; muscle shortens while tension develops to overcome or move some resistance
Eccentric Contraction
Negative contraction; the resistance is greater than the muscular force being produced, and the muscle lengthens while producing tension