Section 6 vocabulary

1. Section 6 vocabulary • Septum: cavities or masses of soft tissue • Process: marked prominance protruding from the bone • Plexus: network of nerves or vessels • Meatus: tube like opening within bone • Lumen: opening within tubular organ or bone • Insertion: site of muscle/tendon attachment • Fossa: pit or depressions • Foramen: natural opening in bone • Flexion: movement at joint that brings bones together • Fascia: Connective tissue beneath skin • Efferent: Carrying fluid or impulses away • Afferent: Carrying fluid or impulses towards an area • Articulation: union between bones • Ampula: sac like • Adduction: movement towards the midline • Abduction: movement away from the midline

2. Introduction to Muscles and Muscular System Mid-point agenda meeting

3. Muscle Coloring Assignment • 30 point quiz grade • If you still do not have a coloring book, photocopy the pages from someone else’s book and give them a buck. • Pages 58-95 • Only color the following: • Pages 59, 61, 65, 69, 71, 73, 75, 83-95 • Do not color: • Pages 63, 67, 77, 79, or 81 • Due the day of the test at the beginning of class • I will no longer be accepting late coloring assignments.

4. Muscles and Muscle Tissue

5. Explain the structure of muscle tissue Describe how an action potential is initiated in a muscle cell Describe the events of a muscle cell contraction Describe three ways in which ATP is regenerated during muscle activity Aims:

6. Overview of Muscle Types The muscular system is composed of three types of muscle tissue: skeletal, smooth, and cardiac muscles. Each type of tissue has a separate function, though all have the similar characteristic of contracting when stimulated.

7. Muscle Types Cardiac – heart Smooth – internal organs Skeletal – "voluntary" Attach to bone Move appendages Support body Antagonistic pairs Flexors Extensors

8. I. Functions of Skeletal Muscle Movement Heat Production Posture Stabilizing Joints

9. II. Characteristics Excitability/ irritability - can be stimulated Contractility- can shorten Extensibility- can stretch Elasticity- can recoil after stretching

10. A. Gross Muscle Anatomy Epimysium- outermost dense irregular connective tissue; covers whole muscle Perimysium- middle fibrous connective tissue; covers fascicles (groups of muscle fibers) Endomysium- innermost reticular connective tissue; covers muscle fiber (skeletal muscle cells)

11. B. Microscopic Skeletal Muscle Anatomy Muscle fiber cell is covered by sarcolemma(cell membrane) and contains sarcoplasm (cytoplasm). Muscle fibers have myofibrils that make the muscle look striated. Myofibrils are the contractile elements of skeletal muscle cells.

12. Microscopic Anatomy Cigar shaped multinucleated cells Voluntary via nervous system controls and reflexes Slow to fast speed of contraction No rhythmic contraction

13. C. Parts of a Myofibril Sarcomere- segment of myofibril between Z lines; functional unit of skeletal muscle A band- wide, dark stripe; thick (myosin) myofilaments I band- narrow, light stripe; thin (actin) myofilaments H zone- lighter band within the A band M line/ band- dark line bisecting the H zone

14. D. Myofilaments • Thin filaments- protein actin. • Also contains troponin & tropomyosin to wrap around actin at muscle rest to block it from interaction with myosin

15. D. Myofilaments • 2. Thick filaments- myosin with “head” attracted to actin

16. IV. Muscle Physiology Neuromuscular Junction Muscle Contraction

17. A. Neuromuscular Junction 1. Each skeletal muscle fiber connects to a fiber from a motor neuron. The connection is a neuromuscular junction or synapse. 2. Here the muscle fiber is specialized into a motor end plate or motor unit.

18. At the end of the neuron are many vesicles which store chemicals called neurotransmitters (ex: Acetylcholine or ACh) When a nerve impulse from the brain or spinal cord reaches the end of a motor neuron fiber, a bit of ACh is released into the gap (synaptic cleft) between the neuron & the motor end plate of the muscle fiber. This stimulates muscle contraction.

19. Sliding Filament Theory of Muscle Contraction States that a myosin cross-bridge can attach to an actin binding site and bend slightly, pulling the actin filament with it. This causes a contraction. Contractions require ATP and ACH.

20. When the muscle receives a nerve impulse, ACH is released into the neuromuscular junction. • Calcium diffuses into the sarcoplasm of the muscle fiber, where it binds to troponin. • When the concentration of calcium ions increases, tropomyosin shifts exposing the binding sites on the actin filaments This leads to linkages between actin and myosin. .

21. When a myosin cross-bridge binds to actin, it pulls actin in toward the H zone at the center of the sarcomere. • As the thin filaments slide past the thick filaments, the entire muscle shortens. • ACHase causes the contraction to cease by breaking down ACH. The Ca ions are actively transported into the sarcoplasmic reticulum. Troponin and tropomyosin return to their original position. • The linkages between the actin and myosin break and the muscle fiber relaxes.