The Muscular System
•An organ system consisting of over 640 muscles •Main functions – •Allows movement in the body •Maintain posture •Stabilize joints Generates heat •Each muscle is a discrete organ made of skeletal muscle tissue, blood vessels, tendons, and nerves. •Also found in the heart, digestive organs, and blood vessels •Muscles serve to move substances throughout the body. Properties of muscles •Excitable or Irritable – capable of receiving and responding to stimulation by nerves (A) •Contractible – capable of shortening (B) •Extensible – can be stretched without damage (C) •Elasticity – able to return to resting shape after being contracted or extended (D) •Adaptability – can change in response to how it’s used, get bigger or smaller (E) Muscle Movement •Voluntary – controlled consciously by a person such as speaking, walking, writing •Involuntary – controlled by the unconscious part of the brain such as heartbeat, intestine moving waste, breathing Types of Muscles •Cardiac – form the wall of the heart and controls your heartbeat – involuntary •Smooth (visceral) –Weakest of all muscle tissues found in organs and perform unique functions like grinding, churning or moving – involuntary •Skeletal – connect to the skeleton in at least one place to move parts of bones closer to each other - voluntary Location of Muscle •Named for the structure near which a muscle is found •Muscle near the Tibia = Tibialis anterior Size of Muscle •Maximus – largest –Gluteus Maximus •Medius – medium -Gluteus Medius Direction of muscle •Rectus– muscle fibers run parallel to midline •Transverse – muscle fibers run perpendicular to midline •Oblique – muscle fibers run diagonal to midline Number of origins of muscle Number of tendons of origin. Prefix determines the number. •Biceps = two •Triceps = three •Quadriceps = four Shape of muscle •Deltoid –having a triangular shape •Trapezius – having a trapezoid shape •Rhomboideus – having a diamond shape •Serratus – having a saw-toothed shape Origin and Insertion •Origin – attached to less or immovable bone •Insertion – attached to the movable bone Connective Tissue Dense layered collagen fibers •Tendons - attach muscle to bone (A) •Facia - surrounds muscles and connects muscle to muscle (B) •Nervous system (3)working with the muscular (2)and skeletal system(1) is essential to the voluntary skeletal muscles. •If nerves are severed, they will not be able to produce muscle movement. Diseases of the Muscular System •Muscular Dystrophy – genetic disease that cause damage of muscle fiber causing weakness, immobility, and imbalance •Cerebral Palsy – congenital disorder that affects the posture, balance, and motor functions •Amyotrophic Lateral Sclerosis (ALS) – Lou Gehrig’s disease – neurodegenerative disease that causes loss of control on voluntary muscles. •Tendonitis – tendons get inflamed or irritated most common in wrists, elbows, shoulders and heels causing pain and swelling Comments are closed.
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Erik E. Mason
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