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MUSCULAR SYSTEM. FUNCTION. THE MAIN FUNCTION OF THE MUSCULAR SYSTEM IS TO MOVE THE BODY. FUNCTION. OTHER FUNCTIONS: Posture or muscle tone Heat production. DID YOU KNOW…. THAT THERE ARE OVER 600 MUSCLES IN THE BODY!!!. MUSCLES ARE ATTACHED TO BONES BY TENDONS
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FUNCTION THE MAIN FUNCTION OF THE MUSCULAR SYSTEM IS TO MOVE THE BODY
FUNCTION OTHER FUNCTIONS: • Posture or muscle tone • Heat production
DID YOU KNOW… THAT THERE ARE OVER 600 MUSCLES IN THE BODY!!!
MUSCLES ARE ATTACHED TO BONES BY TENDONS • LIGAMENTSATTACH BONE TO BONE
TYPES OF MUSCLES There are three different types of muscles: • Skeletal muscle • Smooth muscle • Cardiac muscle
SKELETAL MUSCLE • Attaches to bones • Responsible for skeletal movements • CNS controls the skeletal muscles • Under conscious, or voluntary, control • The basic unit is the muscle fiber with many nuclei • These muscles are located all over the body (there are approximately 639 skeletal muscles)
SMOOTH MUSCLE • Found in the walls of the hollow internal organs • Under control of the autonomic nervous system • Cannot be controlled consciously • Smooth muscle cell is spindle-shaped and has one central nucleus • Contracts slowly and rhythmically
CARDIAC MUSCLE • Found in the walls of the heart • Under control of the autonomic nervous system • Has one central nucleus • Cardiac muscle cell is rectangular in shape • The contraction of cardiac muscle is involuntary, strong, and rhythmical
SKELETAL MUSCLES • ORIGIN OF MUSCLE – THE MORE IMMOBILE OR STATIONARY ATTACHMENT (USUALLY PROXIMAL) • INSERTION OF MUSCLE – THE MORE MOVABLE PART (USUALLY DISTAL) • THE MUSCLE CROSSES THE JOINT AND PULLS THE INSERTION SITE FOR CONTRACTION OF THE MUSCLE
SYNERGISTIC MUSCLES • MUSCLES WITH THE SAME FUNCTION OR THAT WORK TOGETHER TO PERFORM A PARTICULAR FUNCTION
ANTAGONIST MUSCLES • MUSCLES WITH OPPOSITE FUNCTIONS • ARE NECESSARY BECAUSE IT CAN ONLY PULL A BONE IN 1 DIRECTION
ROLE OF THE BRAIN • THE NERVE IMPULSES FOR MOVEMENT COME FROM THE FRONTAL LOBES OF THE CEREBRUM • THE MOTOR AREA GENERATES IMPULSES AND CAUSES CONTRACTION
ROLE OF THE BRAIN • THE CEREBELLUM CONTROLS CONTRACTION AND RELAXATION OF MUSCLES AND COORDINATION
MUSCLE TONE • A STATE OF SLIGHT CONTRACTION • ONLY SOME OF THE MUSCLE FIBERS CONTRACT AT A TIME AND THEY ALTERNATE TO PREVENT FATIGUE
MUSCLES NEED ATP TO CONTRACT • MUSCLE FIBERS PRODUCE HEAT, ABOUT 25% OF THE TOTAL BODY HEAT AT REST
ENERGY USE • ATP BUT IT IS DEPLETED IN A FEW SECONDS • CREATINE PHOSPHATE • GLYCOGEN – THE MOST ABUNDANT ENERGY SOURCE
GLYCOGEN GLUCOSE CELL RESPIRATION BREAKS DOWN GLUCOSE AND ATP IS PRODUCED GLUCOSE + OXYGEN CARBON DIOXIDE + WATER + ATP + HEAT
TYPES OF EXERCISE • ISOTONIC – MUSCLES CONTRACT TO BRING ABOUT MOVEMENT • AEROBIC • IMPROVES MUSCLE TONE, STRENGTH, AND SIZE OF MUSCLES
TYPES OF EXERCISE • ISOMETRIC – INVOLVES THE CONTRACTION OF A MUSCLE WITHOUT MOVEMENT • INCREASES MUSCLE TONE AND STRENGTH • NOT AEROBIC
MUSCLE SENSE • THE BRAIN’S ABILITY TO KNOW WHERE OUR MUSCLES ARE AND WHAT THEY’RE DOING
EACH MUSCLE FIBER HAS THOUSANDS OF CONTRACTING UNITS CALLED SARCOMERES THAT ARE ARRANGED END TO END IN CYLINDERS CALLED MYOFIBRILS • Z LINES ARE THE BOUNDARIES OF A SARCOMERE
OXYGEN SOURCES • HEMOGLOBIN (Hgb) – CARRIES OXYGEN ON THE RED BLOOD CELLS • MYOGLOBIN – THE PROTEINS IN MUSCLE FIBERS THAT STORE OXYGEN • IRON IS NECESSARY TO BIND THE OXYGEN
LACTIC ACID • WHEN THE BODY RUNS OUT OF OXYGEN, IT’S CALLED OXYGEN DEBT • THE INTERMEDIARY IS CALLED LACTIC ACID • IT CAUSES MUSCLE FATIGUE
HOW CONTRACTIONS OCCUR • SLIDING FILAMENT THEORY – THE NERVE IMPULSE ARRIVE AT THE AXON TERMINAL AND STIMULATES THE RELEASE OF ACETYLCHOLINE • THIS GENERATES ELECTRICAL IMPULSES AT THE SARCOLEMMA • MYOSIN FILAMENTS PULL ACTIN FILAMENTS TO THE CENTER OF THE SARCOMERE
MUSCLE FIBERS • EACH MUSCLE FIBER HAS ITS OWN MOTOR NERVE ENDING CALLED THE NEUROMUSCULAR JUNCTION • THIS IS WHERE THE MOTOR NEURON TERMINATES ON THE MUSCLE FIBER
THE AXON TERMINAL IS THE ENLARGED TIP OF THE MOTOR NEURON AND IT CONTAINS SACS OF NEUROTRANSMITTERS • THE MEMBRANE OF THE MUSCLE FIBER IS THE SARCOLEMMA THAT CONTAINS RECEPTOR SITES FOR NEUROTRANSMITTERS • THE SYNAPSE IS BETWEEN THE AXON TERMINAL AND THE SARCOLEMMA
MYOSIN AND ACTIN ARE THE CONTRACTILE PROTEINS • TROPONIN AND TROPOMYOSIN ARE THE INHIBITORY PROTEINS