muscular system. the muscular system muscles are responsible for all types of body movement three...
TRANSCRIPT
Muscular System
The Muscular System•Muscles are responsible for all types of body movement
•Three basic muscle types are found in the body
•Skeletal muscle•Cardiac muscle•Smooth muscle
Characteristics of Muscles
• Muscle cells are elongated (muscle cell = muscle fiber)
• Contraction of muscles is due to the movement of microfilaments
• All muscles share some terminology
• Prefix myo refers to muscle• Prefix mys refers to muscle• Prefix sarco refers to flesh
Muscular System Functions
• The main function of the muscular system is to move your bones.
Voluntary Muscle
• Voluntary muscles are under your conscious control for things like running, grabbing, and other activities.
Video Notes Anatomy Muscular System Voluntary
Skeletal Muscle
• Skeletal muscles are voluntary, connected to bones, and are responsible for your movement.
Skeletal Muscle Characteristics• Most are
attached by tendons to bones
Skeletal Muscle Characteristics• Cells are multinucleate• Striated – have visible banding• Voluntary – subject to conscious control• Cells are surrounded and bundled by connective
tissue
Function of Muscles• Produce movement
• Maintain posture
• Stabilize joints
• Generate heat
Nerve Stimulus to Muscles
• Skeletal muscles must be stimulated by a nerve to contract
• Motor unit• One neuron• Muscle cells stimulated
by that neuron
Muscles and Body Movements• Movement is attained
due to a muscle moving an attached bone
Muscles and Body Movements
• Muscles are attached to at least two points
• Origin – attachment to a moveable bone
• Insertion – attachment to an immovable bone
Muscles work in pairs.
• Muscles can only contract or pull, not push and are controlled by electrical impulses from the brain.
Muscles work in pairs.
• Because muscle cells can only contract, not extend, skeletal muscles must work in pairs.
Muscles work in pairs.
• While one muscle contracts, the other muscle in the pair returns to its original length.
Muscles work in pairs.
• Flexors bend parts of your body.
• Extensors straighten parts of your body.
Levers In Your Body
• Bones and muscles make levers which are machines that make it easier to lift and move things.
Lever Systems and Leverage• bones act as levers
• joints are the fulcrums
• levers can operate • at a mechanical advantage
• when a smaller effort can move a heavier load
• mechanical disadvantage • when a larger effort moves lighter load
• position of effort, load, and fulcrum on lever determine mechanical advantage or disadvantage
Levers In Your Body
• Levers achieve mechanical advantage: a measure of how much easier it is to lift or move something.
Naming Skeletal Muscles• Most skeletal muscle names contain
combinations of word roots for their features1. size
2. shape
3. action
4. number of origins
5. location of muscle
6. sites of origin and insertion
Involuntary Muscle
• Involuntary muscles are not under your conscious control and are responsible for things like breathing and digesting food.
Video Notes Anatomy Muscular System Involuntary
Muscular System Functions
• The muscular system is responsible for the beating of your heart.
Cardiac Muscle
• Cardiac muscle is involuntary and only found in the heart.
Video Notes Anatomy Muscular System Smooth and Cardiac Muscle
Cardiac Muscle Characteristics• Has striations
• Usually has a single nucleus
• Joined to another muscle cell at an intercalated disc
• Involuntary
• Found only in the heart
Muscular System Functions
• The muscular system pushes food and other materials through your body.
Smooth Muscle
• Smooth muscle is involuntary, found in the digestive tract, and helps to move food and materials through your body.
Smooth Muscle Characteristics
• Has no striations
• Spindle-shaped cells
• Single nucleus
• Involuntary – no conscious control
• Found mainly in the walls of hollow organs
Effects of Exercise on MuscleAerobics result in stronger muscles due to increase blood supply Muscle fibers increase mitochondria and oxygen storage Muscle becomes more fatigue resistantHeart enlarges to pump
more blood to bodyDoes not increase skeletal
muscle size
• Results of increased muscle use from resistance training
• Individual muscle cells make more contractile filaments & connective tissue increases
• Increase in muscle size• Increase in muscle strength
Effects of Exercise on Muscle
Types of Ordinary Body Movements
• Flexion
• Extension
• Rotation
• Abduction
• Circumduction
Body Movements
Body Movements
Muscular Dystrophy
• Congenital muscle-destroying disease affect specific muscle groups
• Muscle fibers degenerate & atrophy due to an absence of dystrophin, a protein that helps keep muscle cells intact
• Most common & serious—Duchenne’s M.D.• Mostly in males (diagnosed between2-6 yrs)• Survival is rare beyond early 30’s• X-linked recessive
Myasthenia gravis
• Rare adult disease caused by antibodies to acetylcholine receptors at the neuromuscular junction which prevents the muscle contraction from occurring
• Drooping upper eyelids, difficulty swallowing & talking, muscle weakness & fatigue
• Death occurs when respiratory muscles cease to function
Aging
• Connective Tissue increases• Amount of Muscle tissue decreases• Muscles become stringier (sinewy)• Body weight declines due to loss of
muscle mass• By age 80, muscle strength usually
decrease by 50% without weight training exercises