1. Chapter 9 Key Terms 1 ActinMyosin OriginInsertion TroponinTropomyosin Electrical Potential Fascia AntagonistsAction Potential SarcomereSkeletal Muscle Smooth MuscleCardiac Muscle AcetylcholineAgonists

2. ANATOMY & PHYSIOLOGY CHAPTER 9: MUSCULAR SYSTEM 2

3. Muscular System  Main function of the muscular system is movement  3 types  Skeletal muscles: move the body in the environment  Smooth muscles: moves substances through body  Cardiac muscles: pumps blood through the body (only found in the heart) 3

4. Types of Muscles  Skeletal  Voluntary, multinucleated, and striated  Long fibers  Smooth  Involuntary, uninucleated, and non-striated  Cardiac  Involuntary, uninucleated, and striated 4

5. Skeletal Muscle  Longest muscle fibers 1. Blood vessel 2. Perimysium 3. Epimysium 4. Muscle Fiber 5. Fascicle 6. Endomysium 7. Tendon 5

6. Skeletal Muscle 6

7. Muscles 7  Motor unit: all the muscle cells innervated by one motor neuron  Muscle cell properties  Excitability: they can be excited by a stimulus  Conductivity: response travels throughout the cell  Contractility: ability to contract  Elasticity: ability to return to its original shape  The interaction of 3 factors control muscle contraction  Neuroelectrical factors, chemical interactions, and energy sources

8. Neuroelectrical factors 8  Resting Potential  Inside of cell is negatively charged, outside is positively charged  Neurotransmitter (acetylcholine) is released from the neuron and causes Na + to rush into the cell  This is known as the electrical potential  This causes the action potential (contraction of the muscle)

9. Chemical Interactions  Troponin and Tropomyosin  Inhibit interaction of actin and myosin  Presence of Ca+ ions moves the tropomyosin to all the myosin to bond with the actin  This interaction causes the contraction 9

10. Energy Sources  ATP is the energy source for contraction to occur  ATP breaks down, releasing energy, allowing the myosin head to “pull” on the actin filament 10

11. Muscle Characteristics  Origin  Fixed attachment of a muscle; the basis for the action  The proximal point of attachment  Insertion  The movable attachment where the effects of the contraction can be seen  The distal point of attachment  General names for muscles are based on the type of movement they produce (flexor, extensor, abductor…) 11

12. Facial Muscles 12

13. Muscles of the body 13

14. Muscles of the body 14