NURS 215 Topic 6 Muscular System PDF

https://www.pinterest.ca/pin/15199717463466154/ Parts of Chapters 4, 9 and 10  There are 3 types of muscle tissue:  Smooth  Cardiac  Skeletal  Skeletal muscles form the “muscular system”  Smooth and cardiac muscle tissue is found in other organ systems  Description...

https://www.pinterest.ca/pin/15199717463466154/ Parts of Chapters 4, 9 and 10  There are 3 types of muscle tissue:  Smooth  Cardiac  Skeletal  Skeletal muscles form the “muscular system”  Smooth and cardiac muscle tissue is found in other organ systems  Description: elongated shape, single central nuclei, no striations, arranged in a sheet-like structure  Function: mainly to move substances along internal passageways (involuntary)  Locations: mainly inside hollow organs  Description: branching cells separated by “intercalated discs”, striated, single nucleus  Function: contract to propel blood (involuntary)  Location: walls of heart  Description: long, cylindrical, multinucleate, striations  Function: voluntary movement  Location: attached to bones, sometimes cartilage and skin  *The rest of this section will focus on skeletal muscle Skeletal Muscles are considered organs There are over 700 skeletal muscles and together they form the muscular system Functions: 1. Body movement 2. Maintenance of posture 3. Temperature regulation 4. Storage of materials 5. Support  Each muscle is comprised of muscle fibers organized into bundles called fascicles  Muscle fibers contain myofibrils  Myofibrils are composed of myofilaments  3 layers of connective tissue surrounding muscles  Provides:  Protection  Sites for blood vessel and nerve distribution  Attachment of the muscle to the skeleton  Endomysium  Electrical insulation  Perimysium  Surrounds fascicles  Epimysium  Entire muscle  Comprised of thick and thin filaments  Thick filaments:  Hundreds of myosin molecules  Each comprised of heads and tails  Heads bind to thin filaments  Thin filaments:  Composed mainly of two strands of filamentous actin (F-actin) twisted around each other  Contains myosin binding sites  Functional unit of thick and thin filaments: sarcomere  Impulse travels (voluntary)  From nervous system to muscle  Each fiber controlled by one motor neuron  The neuromuscular junction  Neuron + muscle  Myofilament interaction  Generates tension  Sliding filament theory:  Myosin heads of thick filaments slide thin filament along  Sarcomere becomes smaller  Lengths of filaments don’t change  Video  Tendon: merger of connective tissue at muscle end  Attachment ▪ Bone, skin, or another muscle  Aponeurosis: thin flattened connective tissue attachment  Cross a joint (generally)  Insertion  The bone which moves (the most)  Origin  The bone which doesn’t move (or moves less)  Muscle tone refers to the constant tension in a resting muscle  Motor units are stimulated randomly to avoid fatigue  Two types of muscle contraction: 1. Isometric contraction: Length is constant; tension is changing 2. Isotonic contraction: Tension is constant; length is changing  Agonist: Contraction produces the movement; also called the prime mover  Example: The triceps brachii is the agonist for forearm extension  Antagonist: A muscle whose action opposes that of an agonist  Example: The biceps brachii is the antagonist for forearm extension; it is antagonistic to the triceps brachii  Synergist: A muscle that assists the agonist in performing its action  Includes stabilizing fixators  What is the name of the connective tissue which surrounds the entire muscle? What about each fascicle?  Briefly describe the sliding filament theory (in general)  What is the difference between the origin and insertion of a muscle?  We will cover several specific muscles in more detail  You are only required to know information on the muscles mentioned here  Please make sure you know the actions, origins and insertions  *For origin and insertion you only need to know the bone(s), not the https://www.magzter.com/articles/3401/223093/5927cc05357b2 specific parts of the bone(s) (I have them listed)  Origin: occipital bone, C7, and all thoracic vertebrae  Insertion: scapula and clavicle  Actions:  Superior fibers: elevate scapula  Middle fibers: retract scapula  Inferior fibers: depress scapula   Origin: Clavicle, sternum, cartilage of ribs  Insertion: humerus  Actions: adducts arm (prime mover), medially rotates arm. Can also aid in arm flexion and pull ribs upwards. (a) Anterior view  Origin: thoracic vertebrae, lumbar vertebrae, illium (os coxae)  Insertion: Humerus  Actions: arm extension (prime mover). Also, can adduct and medially rotate arm  Origin: clavicle and scapula  Insertion: Humerus  Actions:  All fibers contracted: prime mover of arm abduction  Anterior fibers: arm flexion  Posterior fibers: arm extension  Anterior compartment  Flexors 1. Biceps brachii  Posterior compartment  Extensors 1. Triceps brachii *There are others as well  Origin: 2 “heads” with different origins on scapula  Insertion: radius  Actions: Flex forearm (prime mover). Can also supinate forearm. Weak flexor of arm.  3 heads, different origins:  Long head: scapula  Lateral and medial heads: humerus  Insertion: Ulna  Actions: Extend the forearm (prime mover). May also stabilize shoulder joint.  Illiacus:  Origin: os coxae (ilium) and sacrum  Insertion: femur (same as psoas major)  Action: thigh flexion (prime mover).  Psoas major:  Origin: lumbar vertebrae and T12  Insertion: femur (same as illiacus)  Actions: thigh flexion (prime mover). Can also flex vertebral column laterally, and maintain posture.  Origin: os coxae (ilium), sacrum, coccyx  Insertion: femur  Action: Thigh extension (prime mover). Can also abduct and laterally rotate thigh.  Origins (2 heads):  Long head: os coxae (ischium)  Short head: femur  Insertion: fibula and tibia (same for both heads)  Actions: flex leg at knee (prime mover). Can also extend thigh.   Origins (4 heads)  Rectus femoris: os coxae  Vastus lateralis: femur  Vastus medialis: femur  Vastus intermedius : femur  Insertion (same for all heads): patella and tibia  Actions:  All: extends leg at knee (prime mover)  Rectus femoris only: flexes thigh *Vastus intermedius not shown is deep (under) the rectus femoris  Compare and contrast the biceps brachii and the triceps brachii in terms of structure, action and location  Name the action, origin and insertion the of the following muscles:  Pectoralis major  Latissimus dorsi  Biceps femoris  Please describe how the muscles (that we covered) allow you to walk forward