Chapter 7 Muscular System PDF

# Seeley's Essentials of Anatomy & Physiology ### Tenth Edition Cinnamon Vanputte Jennifer Regan Andrew Russo See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. # Chapter 7 ## Muscular System ### Lecture Outline ## Types of Muscles ### Skelet...

# Seeley's Essentials of Anatomy & Physiology ### Tenth Edition Cinnamon Vanputte Jennifer Regan Andrew Russo See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. # Chapter 7 ## Muscular System ### Lecture Outline ## Types of Muscles ### Skeletal - attached to bones - striated - voluntarily controlled ### Cardiac - located in the heart - striated - involuntarily controlled ### Smooth - located in blood vessels, hollow organs - non-striated - involuntarily controlled ## Comparison of Skeletal, Cardiac, and Smooth Muscles | Characteristics | Skeletal | Cardiac | Smooth | |-------------------------|-----------------------------------------------|--------------------------------------------------------------|----------------------------------------------------------------| | Body location | Attached to bones or, for some facial muscles to skin | Walls of the heart | Mostly in walls of hollow visceral organs | | Cell shape and appearance | Single, very long, cylindrical, multi-nucleate cells with very obvious striations | Branching chains of cells; uninucleate, striations; intercalated discs | Single, fusiform, uninucleate, no striations | | Connective tissue components | Epimysium, perimysium, and endomysium | Endomysium attached to the fibrous skeleton of the heart | Endomysium | | Regulation of contraction | Voluntary, via nervous system control | Involuntary; the heart has pacemaker; nervous system control; hormone | Involuntary; nervous system controls; hormones, chemicals | | Speed of Contraction | Slow to fast | slow | Very slow | | Rhythmic contraction | No | Yes | Yes, in some | ## Muscle Fiber Structure ### Skeletal Muscle Fiber - A single cylindrical cell with several nuclei located at its periphery - Range in length 1 cm to 30 cm and are generally 0.15 mm in diameter - Skeletal muscle fibers contain several nuclei that are located at the periphery of the fiber. - The *sarcolemma* (cell membrane) has many tubelike inward folds, called transverse tubules, or *T tubules*. ### T Tubules - Occur at regular intervals along the muscle fiber and extend into the center of the muscle fiber. - Are associated with enlarged portions of the smooth endoplasmic reticulum called the *sarcoplasmic reticulum*. ### Sarcoplasmic Reticulum - The enlarged portions are called *terminal cisternae*. - T tubules connect the sarcolemma to the terminal cisternae to form a *muscle triad*. ### Sarcoplasm - Is the cytoplasm of a muscle fiber - Which contains many bundles of protein filaments. ### Myofibrils - Are bundles of protein filaments. - Consist of the *myofilaments*, *actin*, and *myosin*. ## The Muscular System ### Functions - Movement - Maintain posture - Respiration - Production of body heat - Communication - Heart beat - Contraction of organs and vessels ## Properties of Muscles ### Contractility - The ability of muscle to shorten forcefully, or contract ### Excitability - The capacity of muscle to respond to a stimulus ### Extensibility - Ability to be stretched beyond it normal resting length and still be able to contract ### Elasticity - Ability of the muscle to recoil to its original resting length after it has been stretched ## Skeletal Muscle Structure ### Skeletal Muscle - Also called *striated muscle* because transverse bands, or striations. ### Connective Tissue Coverings - **Epimysium:** A connective tissue sheath that surround each skeletal muscle. - A skeletal muscle is subdivided into groups of muscle cells, termed **fascicles**. - **Perimysium:** Surround the fascicle. - **Endomysium:** Surround each skeletal muscle cell (fiber). ## Muscles of the Head and Neck - Facial muscles - Mastication or chewing tongue - Swallowing muscles - Eyes muscles - Head and neck muscles ## Muscles of Facial Expression and Mastication ## Chewing Muscles 1. **Masseter:** Closes the jaw by elevating and pushing the mandible anteriorly. 2. **Temporalis:** Elevates and draws mandible posteriorly 3. **Pterygoid:** - **Lateral:** Pushes the mandible anteriorly and depresses mandible; close the jaw - **Medial:** Pushes the mandible anteriorly and elevates mandible: closes the jaw ## Tongue and Swallowing Muscles ### Tongue Muscles - **Intrinsic:** Change the shape of the tongue - **Extrinsic:** Moves the tongue ### Hyoid Muscles - **Suprahyoid (geniohyoid, stylohyoid, hyoglossus):** Elevates or stabilizes hyoid - **Infrahyoid:** Depresses or stabilizes hyoid ## Deep Neck Muscles 1. **Neck Flexors:** Originate on the anterior side of the vertebrae which flex the head and neck. 2. **Neck Extensor:** Originate on the posterior side of the vertebrae that extend the head and neck. - **Sternocleidomastoid:** Individually rotate the head; together it flexes the neck. - **Platysma:** Pull the corners of the mouth inferiorly - **Trapezius:** Extends and laterally flexes the neck. ## Trunk Muscles - Vertebral column - Thorax - Abdominal wall - Pelvic floor ### Muscles of the Vertebral Column - **Erector Spinae:** Extends vertebral column and maintains posture, divides in 3 column; Iliocostalis, longissimus, Spinalis. ### Deep Neck and Back Muscles - Located between spinous and transverse processes adjacent to vertebrae - Responsible for movement of vertebral column including extension, lateral flexion, and rotation. - Torn or stretched of these muscles cause sprain and strain. ### Thoracic Muscles - **Scalenes:** Elevates the ribs during inspiration - **External intercostals:** Elevate ribs for inspiration. - **Internal intercostals:** Depress ribs during forced expiration. - **Diaphragm:** Moves during quiet breathing. ### Muscles of the Thorax - **Scalenes** - **External intercostals** - **Internal intercostals** - **Diaphragm** ### Abdominal Wall Muscles 1. **Rectus abdominis:** - Center of abdomen - Compresses abdomen 2. **External abdominal oblique:** - Sides of abdomen - Compresses abdomen ### Abdominal Wall Muscles 1. **Internal abdominal oblique:** Compresses abdomen 2. **Transverse abdominis:** Compresses abdomen