1. Muscles

2. Types of Muscle 4 Smooth - involuntary 4 Skeletal - voluntary 4 Cardiac - involuntary

4. Smooth Muscle 4 Involuntary 4 Lines digestive system 4 Lines blood vessels 4 Contracts bladder 4 Contracts uterus 4 Few nuclei, no striations 4 Movements involve many muscles at a time

5. Cardiac Muscle 4 Found only in heart 4 Striated like skeletal muscle 4 Involuntary like smooth muscle 4 Pushes blood out of the heart

6. Skeletal Muscle 4 Under voluntary control 4 Moves arms, legs, head 4 Allows us to change body position, move 4 Produces most of body heat 4 Many striations, many nuclei 4 Pull on bone

7. Structure of Skeletal Muscle 4 Draw figure 37.10 in your notes here. 4 Muscles are made of individual bundles. 4 Each bundle is enclosed by a sarcolemma 4 Within each sarcolemma are many sarcomeres

8. Skeletal Muscle Structure

10. Skeletal Muscle (cont.) 4 Each sarcomere is bounded by two Z lines 4 Each sarcomere is made of actin and myosin strands

11. Sliding Filament Theory 4 Basic theory of muscle contraction. 4 Two filaments, actin & myosin, interact within the sarcomere 4 Length of A band doesn’t change. 4 I-band and H-zone shorten during contraction. 4 Filaments slide past each other but do not shorten themselves.