1. Muscular and Skeletal Systems

2. I. Muscular System A. Types B. Major Groups

3. A. Types 1) Skeletal Provide movement for the skeleton Most are consciously controlled by the central nervous system Contain striations Have many nuclei Function by nervous stimulation Motor neurons connected to muscle Composition: many fibers stacked together in bundles Composition:

4. Composition Muscles composed of bundles of fibers Within each bundle there are individual fibers containing: Myofibril – Organized filament made of thin and thick proteins Actin – Protein component of thin filaments Myosin – Protein component of thick filaments Sarcomere – Smallest contractile unit in muscle fiber Z Line – Dividing line between 2 sarcomeres

5. Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin Figure 36-8 Muscle Contraction Section 36-2

6. Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin Figure 36-8 Muscle Contraction Section 36-2 During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge.

7. Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin Figure 36-8 Muscle Contraction Section 36-2 During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge. Powered by ATP, the myosin cross- bridge changes shape and pulls the actin filament toward the center of the sarcomere.

8. Relaxed Muscle Contracted Muscle Z lineMyosinActinZ line Sarcomore Cross-bridgesZ line Movement of Actin Filament Actin Binding sites Cross- bridge Myosin Figure 36-8 Muscle Contraction Section 36-2 During muscle contraction, the knoblike head of a myosin filament attaches to a binding site on actin, forming a cross-bridge. Powered by ATP, the myosin cross- bridge changes shape and pulls the actin filament toward the center of the sarcomere. The cross-bridge is broken, the myosin binds to another site on the actin filament, and the cycle begins again.

9. 2. Smooth Muscles Not under voluntary control Spindle-shaped One nucleus Not necessary for nervous stimulation to function Gap junctions allow impulse to travel from muscle-cell to muscle-cell Locations: Lines hollow organs (except heart) Lining of blood vessels Eyes A. Types Cont.

10. 3.Cardiac Muscle Involuntary control Striated Usually one nucleus but may have two Muscles are connected by gap junctions Found only in the heart

11. Biceps Deltoid Trapezius Pectoral Triceps Abdominalis Triceps Deltoid Quadriceps Gluteus Maximus Gastrocnemius Sartorius Gastrocnemius radialis Biceps Trapezius Hamstring Latissimus B. Major Groups

12. II. Skeletal System A. Structure B. Development C. Joints D. Major Bones E. Movement

13. A. Structure Structure 1.Bones Living cells and protein surrounded by calcium deposition Direct blood supply Periosteum – connective tissue surrounding bone Bone Marrow – cavity in bone containing soft tissueBone Marrow Red Marrow – Produces R.B.C.’s some W.B.C.’s and platelets Yellow Marrow – Made of fat cells 2 Types Spongy Inner Layer of bone Contains Red Marrow Compact Outer layer Osteocytes – Mature Bone cells Osteoclasts – Breakdown bone Osteoblasts – Create bone

14. Spongy Bone Compact Bone Periosteum Bone Marrow Spongy Bone Compact Bone Haversian Canal Osteocyte Artery Vein Periosteum

16. B. Development 1. As We Grow Embryonic Skeleton - Primarily composed of cartilage (elastic tissue that does not contain blood vessels)Embryonic Skeleton - Primarily composed of cartilage (elastic tissue that does not contain blood vessels) Cartilage is replace by bone through a process called ossificationCartilage is replace by bone through a process called ossification Occurs up to 7 months before birth Occurs up to 7 months before birth The body does not completely ossify to facilitate child birthThe body does not completely ossify to facilitate child birth Osteoblasts secrete minerals deposits (forming bone) Osteoblasts secrete minerals deposits (forming bone) As the osteoblasts become surrounded by bone tissue the mature into ostocytes As the osteoblasts become surrounded by bone tissue the mature into ostocytes Growth PlatesGrowth Plates Sites each end of the bone that contains growing cartilage Sites each end of the bone that contains growing cartilage As the cartilage gets replaced by bone we stop growing As the cartilage gets replaced by bone we stop growing

17. Ball-and-Socket Joint Hinge Joint Pivot Joint Clavicle Ball-and- socket joint Scapula Humerus Femur Patella Hinge joint Tibia Fibula Humerus Radius Pivot joint Ulna Metacarpals Carpals Saddle joint Saddle Joint C. Joints

18. D. Major Bones Skull Sternum Ribs Vertebral column Metatarsals Metacarpals Phalanges Clavicle Scapula Humerus Radius Pelvis Ulna Carpals Femur Patella Fibula Tibia Tarsals Phalanges Appendicular Skeleton

19. E. Movement Movement occurs between the coordination of the skeletal and muscular systems 1.Tendons Bundles of connective tissue that link muscle to bone Bundles of connective tissue that link muscle to bone Damage is usually irreversible Damage is usually irreversible 2.Ligaments Bundles of connective tissue that link bone to bone Bundles of connective tissue that link bone to bone Common ailment is a torn ACL Common ailment is a torn ACL