THE MUSCULAR SYSTEM UNIT F

The Power system! Nearly half our weight comes from muscle tissue. There are 650 different muscles in the human body. Muscles give us form and shape. Muscles produce most of our body heat.

3 main functions Responsible for all body movement Responsible for body form and shape (posture) Maintain body temp. and producing heat

Types of muscle TYPES OF MUSCLES SKELETAL SMOOTH CARDIAC

SKELETAL MUSCLE Attached to bone Striated (striped) appearance VOLUNTARY!!!!!

SKELETAL MUSCLE cont. Sarcolemma = cell membrane Multinucleated muscle cell bundles Muscle cell =muscle fiber Contract quickly, fatigue easily, can’t contract for a long time

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Types of Muscles Skeletal muscle.Skeletal muscle. Attached to bone.Attached to bone. Striated (striped) appearance.Striated (striped) appearance. Voluntary.Voluntary. Multinucleated muscle cell bundles (muscle cells = muscle fibers).Multinucleated muscle cell bundles (muscle cells = muscle fibers). Sarcolemma = cell membrane.Sarcolemma = cell membrane. Contract quickly, fatigue easily, can’t maintain contraction or long period of time.Contract quickly, fatigue easily, can’t maintain contraction or long period of time.

SMOOTH MUSCLE Only one nucleus Unattached to bones They do not tire easily and contract for long periods Involuntary

Smooth cont. Found in walls of digestive system, uterus and blood vessels Controlled by autonomic nervous system

Types of Muscles Cont. Smooth muscle.Smooth muscle. Visceral (organ) muscle.Visceral (organ) muscle. Found in walls of digestive system, uterus and blood vessels.Found in walls of digestive system, uterus and blood vessels. Cells small and spindle-shaped.Cells small and spindle-shaped. Involuntary.Involuntary. Controlled by autonomic nervous system.Controlled by autonomic nervous system. Act slowly, do not tire easily, can remain contracted for long time.Act slowly, do not tire easily, can remain contracted for long time.

CARDIAC MUSCLE Found ONLY in the HEART Striated and branched Involuntary Cells are fused when 1 contracts they all do

Types of Muscle Cont. Cardiac muscle.Cardiac muscle. Found only in the heart. Striated and branched. Involuntary. Cells are fused- when one contracts, they all contract.

Sphincter Special circular muscles in openings of esophagus and stomach, stomach and small intestine, anus, urethra and mouth.

Characteristics of Muscles Contractibility = ability of a muscle to reduce the distance between the parts of its contents or space it surrounds

Characteristics cont. Excitability = (irritability) the ability to respond to certain stimuli by producing impulses

Characteristics cont. Extensibility – the ability to be stretched Elasticity – ability of muscle to return to its original length when relaxing

Movement Move bones by pulling on them As a muscle contracts it pulls the insertion bone closer to the origin bone. Movement occurs at the joint Go to video

RULE A muscle’s insertion bone moves toward its origin bone

Movement cont. Groups of muscles contract to produce a single movement

Movement Cont. Motor Unit – a motor neuron plus all the muscle fibers it stimulates

Movement cont. Neuromuscular Junction – the junction between the motor neuron’s fiber which transmits the impulse

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Movement cont. Acetylcholine – chemical neurotransmitter, diffuses across the synaptic cleft ( carries the impulse across synaptic cleft.)

Movement cont. Muscle Fatigue – Caused by the accumulation of lactic acid in the muscles

Muscle cont. Oxygen Debt - After exercise the amount of oxygen needed by the muscle to change lactic acid back to glucose

Muscle cont. Muscle Tone - Muscles are slightly contracted and ready to pull

Muscle cont. Diaphragm - Dome shaped muscle that separates the abdominal and thoracic cavities and aids in breathing.

The muscles

32DISORDERS32

33Atrophy Wasting away of muscle due to lack of use.Wasting away of muscle due to lack of use. 33

34Hypertrophy an increase in the size of the muscle cellan increase in the size of the muscle cell

35 Strain vs. Sprains Strain- affect muscles or tendonsStrain- affect muscles or tendons also called pulled musclealso called pulled muscle muscle becomes overstreched and tearsmuscle becomes overstreched and tears

36Sprains affect ligamentsaffect ligaments usually from traumausually from trauma you overstretch ligament or tear ligamentyou overstretch ligament or tear ligament PAINFULPAINFUL 36

37 Muscle Spasm CrampCramp sustaind contraction of musclesustaind contraction of muscle due to overusedue to overuse 37

38Myalgia Muscle PainMuscle Pain 38

39Tendonitis Inflammation of a tendonInflammation of a tendon 39

40 Muscular Dystrophy Gentic disorderGentic disorder weaking musclesweaking muscles Different degreesDifferent degrees

41 THE END