Unit Five The Muscular System

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1 Unit Five The Muscular System I. Introduction A. Definition: the muscular system is composed of all the muscles of the body including the movements of the total body, as well as movements the body. B. Properties of Muscle Tissue 1. the ability of muscle tissue to shorten or contract. 2. the ability of muscle tissue to be extended or stretched within limits. 3. the ability of muscle tissue to return to its original state after being stretched. 4. the susceptibility of muscle tissue to react to external stimuli. 5. the state in which muscle is partially contracted allowing it to react instantly when stimulated. C. Classification of Muscle Based on Nervous Control 1. muscle is muscle not subject to conscious control A. and muscle are of this type 2. muscle is muscle subject to conscious control B. is of this type

D. Terminology 1. Special terms for cellular parts of the muscle: A. - muscle cell membrane B. - muscle cell cytoplasm C. - muscle cell SARKOS FLESH LEMMA HUSK PLASM - JELLY 2.

2 D. Terminology 1. Special terms for cellular parts of the muscle: A. - muscle cell membrane B. - muscle cell cytoplasm C. - muscle cell SARKOS FLESH LEMMA HUSK PLASM - JELLY 2. - connect muscle to bone, tough tissue fibers. 3. Origin- point of muscle attachment. 4. Insertion- point of muscle attachment. 5. Action- movement a particular muscle produces. 6. Innervation- supply to a muscle. 7. Muscle belly- that part of the muscle the origin and the insertion. Diagram of a muscle and its attachments:

II. Physiology of Skeletal Muscle Cells (or Muscle Fibers) A. Diagram of a muscle fiber: B. Enormous, large diameter and up to long. C. Multinucleated 1. Hundreds of just below the sarcolemma.

3 II. Physiology of Skeletal Muscle Cells (or Muscle Fibers) A. Diagram of a muscle fiber: B. Enormous, large diameter and up to long. C. Multinucleated 1. Hundreds of just below the sarcolemma. The many nuclei are needed because of the high metabolic rate and protein needed for muscle. D. Myoblasts (myo = muscle, blast = precursor) 1. During development, groups of called myoblasts fuse together to create individual skeletal muscle fibers. 2. Each in a skeletal muscle fiber is the result of a single myoblasts. E. Myofibril 1. A cylindrical structure as long as the entire muscle cell. 2. Each skeletal muscle cell contains hundreds to thousands of. 3. Myofibrils can actively due to their structure.

F. Sarcomere (sarkos = flesh, meros= part) 1. Myofibrils are divided into sections called sarcomeres. 2. The sarcomere is the functional unit of a myofibril. 3.

4 F. Sarcomere (sarkos = flesh, meros= part) 1. Myofibrils are divided into sections called sarcomeres. 2. The sarcomere is the functional unit of a myofibril. 3. The sarcomere contains sections of the actin and myosin microfilaments. A. filaments are thin and made up of the protein actin B. filaments are thick and made up of the protein myosin 4. The interactions between actin and myosin result in contraction. 5. Schematic of a sarcomere: The Sliding Filament Theory

5 III. Types of Muscle Tissue A. muscle (striated, voluntary) 1. Connected to and responsible for the movement of bones. 2. Has a band-like appearance (striated) because of alternating light and dark areas due to the arrangement of actin and myosin microfilaments. 3. Is controlled by the nervous system. 4. Has multinucleated cells due to their enormous size. B. muscle (striated, involuntary) 1. Is only in heart. 2. Striations visible because the actin and myosin microfilaments are Arranged the same way in both skeletal and cardiac fibers. 3. Cardiac muscle fibers do not require nerve activity to stimulate contraction, pacemaker cells establish a regular rate of contraction. C. muscle (nonstriated, involuntary) 1. Is found in many places (ex-blood vessels, digestive organs). 2. Can contract on their own or from nerve activity but the nerve control would still be involuntary. 3. A smooth muscle fiber is a small, spindle-shaped cell with tapering ends, containing a single nucleus. D. Microscopic appearance of muscle fibers: 1. Smooth muscle 2. Cardiac muscle 3. Skeletal muscle

6 What is muscle type: I? How did you know? II? How did you know? III? How did you know? Add as many more characteristics to the Venn Diagram as possible.

IV. Functions of Muscles A. Allows 1. Movement of - skeletal muscles move the body by on bones of skeleton. 2. Movement of : A. muscle tissues pushes blood through the circulatory system. B.

7 IV. Functions of Muscles A. Allows 1. Movement of - skeletal muscles move the body by on bones of skeleton. 2. Movement of : A. muscle tissues pushes blood through the circulatory system. B. muscle tissue regulates the diameters of arteries. 3. Movement of - muscle pushes fluids and solids along the digestive tract (alimentary canal). V. Structure of Skeletal Muscle A. Muscle fiber- multinucleated and surrounded by a connective sheath, called. B. Fasciculus- groups of muscle fibers surrounded by a connective tissue called. C. Muscle belly- groups of fasciculi come together and are surrounded by connective tissue called. C. Diagram of the cross section of a muscle belly: a. Layers of the muscle (perimysium, epimysium, endomysium)

8 VI. Skeletal Muscles A. Physiology 1. Must work in 2. Muscles bones (Biceps pull forearm up, triceps pull forearm down.) 3. Muscles can only ; they cannot stretch themselves (they relax and allow themselves to be stretched). B. Muscle growth and loss 1. Muscles hypertrophy: 2. Muscle hyperplasia: 3. Muscle atrophy: C. Match the following muscles to the diagram: 1. Biceps brachii 6. Pectoralis major 11. Sartorius 2. Rectus femoris 7. gluteus maximus 12. Deltoid 3. Latissimus dorsi 8. Sternocleidomastoid 13. Biceps femoris 4. Rectus abdominous 9. Triceps brachii 14. Trapezius 5. Gastrocnemius 10. Frontalis 15. Achilles tendon

The Muscular System. Biology 105 Lecture 12 Chapter 6

The Muscular System. Biology 105 Lecture 12 Chapter 6 The Muscular System Biology 105 Lecture 12 Chapter 6 Outline I. Characteristics of muscles II. Three types of muscles III. Functions of muscles IV. Structure of skeletal muscles V. Mechanics of muscle