Thursday, November 12, 2015 Put muscular worksheet in the blue basket Get a textbook Get a highlighter Get out paper & something to write with

FYI… A muscle cell is also called a muscle fiber

Read pgs on your paper answer the following

1. Describe the similarities and differences in the structure and function of the 3 types of muscle tissue, and indicate where they are found in the body.

2. Define muscular system. Organ system consisting of skeletal muscles and their connective tissue attachments

3. Define and explain the role of the following: endomysium, perimysium, epimysium, tendon, and aponeurosis.

Endomysium Connective tissue sheath that encloses each muscle fiber

perimysium Coarse fibrous membrane that encloses several sheathed muscle fibers / surrounds a bundle of fibers called a fascicle

Epimysium Tough, outer covering that bind together many fascicles; covers the entire muscles and blends into the tendons or aponeuroses; covered with fascia

Both connect muscles indirectly to bones, cartilages, or connective tissue coverings Tendons Cordlike Provide durability & conserve space Aponeuroses sheetlike

Thick and thin filaments Filaments Myofibrils Myofibril Muscle fibers (cells) Muscle fiber Sarcolemma Nucleus Sarcoplasmic reticulum Fascicles Fascicle Axon of motor neuron Blood vessel A skeletal muscle is composed of a variety of tissues Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Muscle Bone Tendon Fascia (covering muscle) Epimysium Perimysium Endomysium

4. Describe the microscopic structure of skeletal muscle and explain the role of actin- and myosin-containing myofilaments

Sarcolemma—specialized plasma membrane Myofibrils—long organelles inside muscle cell Sarcoplasmic reticulum—specialized smooth endoplasmic reticulum

Myofibrils are aligned to give distinct bands – I band = light band Contains only thin filaments – A band = dark band Contains the entire length of the thick filaments

Sarcomere—contractile unit of a muscle fiber Organization of the sarcomere –M–Myofilaments Thick filaments = myosin filaments Thin filaments = actin filaments

Thick filaments = myosin filaments – Composed of the protein myosin – Has ATPase enzymes – Myosin filaments have heads (extensions, or cross bridges) – Myosin and actin overlap somewhat Thin filaments = actin filaments – Composed of the protein actin – Anchored to the Z disc

At rest, there is a bare zone that lacks actin filaments called the H zone Sarcoplasmic reticulum (SR) – Stores and releases calcium – Surrounds the myofibril

Extra Credit Due Wednesday, November 18, 3015 Make a model of skeletal muscle Use Figure 6.1 as a guide Must label – Muscle fiber (cell) – Fascicle – Perimysium – Endomysium – Epimysium – fascia

Homework watch 5 videos on the Sliding Filament Theory of Muscle Contraction