Human Systems Muscular System

Definition: Definition: All the muscles in your body All the muscles in your body Muscles: Muscles: Body tissue that can change shape & length, causing movement Body tissue that can change shape & length, causing movement

Muscular System

Muscles Main Action Deltoid Raises your arm sideways at the shoulder. Biceps Bends your arm at the elbow. Abdominals (4 muscles) Pull in the abdomen. Flex the spine so you can bend forward. Quadriceps (4 muscles) Straighten the leg at the knee. Keep it straight when you stand. Pectoral Raises your arm at the shoulder. Draws it across your chest. Latissimus Dorsi (lats) Pulls your arm down at the shoulder. Draws it behind your back. Trapezius Holds and rotates your shoulders. Moves your head back and sideways. Triceps Straightens your arm at the elbow joint. Gluteals (3 muscles) Pull your leg back at the hip. Raise it sideways at the hip. Hamstrings (3 muscles) Bend your leg at the knee. Gastrocnemius Straightens the ankle joint so you can stand on your tiptoes.

Muscles - Structures Skeletal – move the bones of skeleton Skeletal – move the bones of skeleton Athletic activity: arms, legs, abdomen, chest & shoulders Athletic activity: arms, legs, abdomen, chest & shoulders Bundles of fibers Bundles of fibers Striped – two proteins make up fibers Striped – two proteins make up fibers Voluntary: muscles you can control Voluntary: muscles you can control Animal tissue you eat Animal tissue you eat

Muscles - Structures

Cardiac – makes up heart Cardiac – makes up heart Only body organ of this type Only body organ of this type Bundles of fibers Bundles of fibers Striped – two proteins make up fibers Striped – two proteins make up fibers Tight weave of fibers Tight weave of fibers Involuntary: muscles you can’t control Involuntary: muscles you can’t control

Muscles - Structures

Smooth – makes internal organs, stomach, intestines & walls of blood vessels Smooth – makes internal organs, stomach, intestines & walls of blood vessels Spindle-shaped Spindle-shaped Not striped Not striped Involuntary: muscles you can’t control Involuntary: muscles you can’t control

Muscles - Structures

Muscles - Function Brain sends messages for muscle to move Brain sends messages for muscle to move Voluntary: you think about movement Voluntary: you think about movement Involuntary: part of your brain programs movement without your thinking about it Involuntary: part of your brain programs movement without your thinking about it

Muscles - Function

Muscles change length and work in PAIRS Muscles change length and work in PAIRS Muscle shortens & thickens: contracting Muscle shortens & thickens: contracting Muscle lengthens: relaxing Muscle lengthens: relaxing Move bones by pulling: connected by tendon – tough, fibrous tissue that connects muscle to bone Move bones by pulling: connected by tendon – tough, fibrous tissue that connects muscle to bone

Muscles - Function Muscles Working in Pairs