Muscular System Tracie Haan M.E. Meyerhofer Chelsea Friesen

Muscular System Physiology  4 main functions of the muscles:  Produces movement  Maintain posture  Reinforces and stabilizes joints  Generates heat

Muscle Types  There are three main muscle types:  Skeletal  Cardiac  Smooth

Skeletal Muscles  The four primary functions of skeletal muscles: Movement Posture Support Heat regulation  Controlled under somatic nervous system  Voluntarily Controlled  Striated  Most skeletal muscles are attached to bones by bundles of collagen fibers known as tendons.

Skeletal Muscle Structure  Skeletal Muscle Cells (myocytes) myoblasts ○ Myofibrils  Skeletal Muscles Belly ○ Fascia: Epimysium Perimysium Endomysium ○ Muscle Fiber (Cell) Tendon

6 Skeletal Muscles Major Muscles: 6

Mechanics Of Movements Demo

Cardiac Muscles  Two types of cardiac cells: Electrical and myocardial  Heats contracts rhythmically the whole life of an organism.  Autonomically controlled, involuntary muscle, polarized  Striated  Cardiac muscles are auto-rhythmic Muscles contract even in the absence of neuronal innervation (pacemaker cells)

Smooth Muscles  All involuntary actions within body with exception to the heart  2 types: Visceral smooth muscle Multiunit smooth muscle  No striations due to the absence of sarcomeres  Some smooth muscle areas include: the walls of the viscera, iris of the eye, urinary tract and blood vessels.  Stimulate movement such as peristalsis

Common Muscular Diseases  Muscular Dystrophy- Group of genetic disorders Muscle weakness and loss of muscle tissue Gets worse over time No cure  Sprains and Strains- Sprain- ○ Stretched or torn ligament ○ Ligaments connect bones at the joints Strain- ○ Stretched or torn tendon or muscle ○ Tendons connect the muscle to the bone

Common Muscular Diseases  Myositis- Inflammation of muscle fibers Swelling of skeletal muscles Group of diseases Causes muscle weakness and degeneration

Contraction and Relaxation Lab 12

Sources   gy__and_Elect/anatomy__physiology__and_elect.html gy__and_Elect/anatomy__physiology__and_elect.html  physiology-muscular-system/ physiology-muscular-system/   