1. Muscular System

4. THE MUSCULAR SYSTEM COMPOSED OF MUSCLE TISSUE SPECIALIZED TO CONTRACT TO PRODUCE MOVEMENT WHEN STIMULATED BY NERVOUS SYSTEM

5. Types of Muscle 1. Skeletal Attaches to & moves bone Attaches to & moves bone Striated (striped) Striated (striped) Voluntary (you can control it) Voluntary (you can control it)

6. 2. Smooth Used in breathing, movement of digestive system, blood, etc.. Used in breathing, movement of digestive system, blood, etc.. Not Striated (no stripes); spindle-shaped Not Striated (no stripes); spindle-shaped Involuntary Involuntary

7. 3. Cardiac Heart Muscle Heart Muscle Striated & Branched Striated & Branched INVOLUNTARY INVOLUNTARY (NO NERVOUS SYSTEM REQUIRED) (NO NERVOUS SYSTEM REQUIRED)

8. MUSCLE STRUCTURE SARCOMERE = STRUCTURAL UNIT OF MUSCLE = MYOSIN = ACTIN = BORDERS OF SARCOMERE PROTEIN FIBERS:

9. Muscle Contraction THIN & THICK FILAMENTS SLIDE PAST ONE ANOTHER (IE.”SLIDING FILAMENT THEORY”)  MUSCLE SHORTENS, OR CONTRACTS !

11. A Muscle Contraction, like a Nerve Impulse, is an All-or-None Response- either Fibers CONTRACT or they Remain RELAXED!!! A Muscle Contraction, like a Nerve Impulse, is an All-or-None Response- either Fibers CONTRACT or they Remain RELAXED!!! ENERGY (ATP) IS REQUIRED !!

12. CONTROL OF MUSCLE CONTRACTION NEUROMUSCULAR JUNCTION = POINT OF CONTACT BETWEEN MOTOR NEURON & SKELETAL MUSCLE RELEASE OF NEUROTRANSMITTER CALLED ACETYLCHOLINE (ACh) IN SYNAPSE !!