Presentation on theme: "MUSCULAR SYSTEM OVERVEIW “the power system”"— Presentation transcript:
1 MUSCULAR SYSTEM OVERVEIW “the power system” Nearly half our weight comes frommuscle tissue.There are 650 different muscles in thehuman body.Muscles give us form and shape.Muscles produce most of our body heat.
2 MUSCLE TYPESSKELETALSMOOTHTYPES OF MUSCLESCARDIAC
3 Skeletal MuscleAttached to boneStriated (striped) appearanceVOLUNTARYMultinucleated muscle cell bundles (muscle cells = muscle fibers)SARCOLEMMA = cell membraneContract quickly, fatigue easily, can’t maintain contraction for long period of time
4 Smooth MuscleVisceral (organ) muscleFound in walls of digestive system, uterus and blood vesselsCells small and spindle-shapedINVOLUNTARYControlled by autonomic nervous systemAct slowly, do not tire easily, can remain contracted for long time
5 Cardiac MuscleFound only in the heartStriated and branchedInvoluntaryCells are fused – when one contracts, they all contract
6 Four important roles in body: MAIN FUNCTIONSFour important roles in body:1. Responsible for all body movement.2. Responsible for body form and shape(posture)3. Stabilize joints4. Responsible for body heat and maintainingbody temperature.
7 SKELETAL MUSCLE ACTIVITY Stimulation and Contraction of Skeletal Muscle CellsEXCITEABILITY (IRRITABILITY) – the ability to respond to certain stimuli by producing impulses.CONTRACTIBILITY – the ability of a muscle to reduce the distance between the parts of its contents or the space it surrounds.
8 SKELETAL MUSCLE ACTIVITY MOTOR UNIT – a motor neuron plus all the muscle fibers it stimulates.NEUROMUSCULAR JUNCTION – the junction between the motor neuron’s fiber which transmits the impulse – and the muscle cell membrane.ACETYLCHOLINE – chemical neurotransmitter, diffuses across the synaptic cleft (carries impulse across synaptic cleft)MUSCLE FATIGUE – caused by the accumulation of lactic acid in the muscles.OXYGEN DEBT – after exercise, the amount of oxygen needed by the muscle to change lactic acid back to glucose.MUSCLE TONE - When muscles are slightly contracted and ready to pull.DIAPHRAGM – Dome-shaped muscle that separates the abdominal and thoracic cavities, aids in breathing
9 MUSCLE CONTRACTIONS Muscle Tone In order to function, muscles should always be slightly contracted and ready to pull.Muscle contractions may be isotonic or isometric.ISOTONIC CONTRACTIONWhen muscles contract and shorten. (Walk, talk, etc.)ISOMETRIC CONTRACTIONWhen the tension in a muscle increasesbut the muscle does not shorten.(exercises such as tensing the abdominal muscles.)
10 MUSCULAR SYSTEM MUSCLE MOVEMENT Muscles move bones by pulling on them. “the power system”MUSCLE MOVEMENTMuscles 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 between the origin and the insertion.2. Groups of muscles usually contract to produce a single movement.3. When the antagonist muscles contract, they produce a movement opposite to that of the prime movers.
11 Anterior Surface of Body Gross Anatomy of Skeletal MusclesAnterior Surface of BodyFrontalisOrbicularis orisSternocleidomastoidsDeltoidPectoralis majorBiceps brachiiIntercostals musclesRectus abdominusExternal obliqueSartoriusQuadriceps group
12 Gross Anatomy of Skeletal Muscles Posterior Surface of Body OccipitallisTrapeziusDeltoidtriceps brachiiLatissimus dorsiGluteus mediusGluteus maximusHamstringsGastrocnemiusSoleusAchilles tendon
13 Disorders and Related Terminology ATROPHY – wasting away of muscle due to lack of use.HYPERTROPHY – an increase in the size of the muscle cell.STRAIN – tear in the muscle resulting from excessive use. Bleeding inside the muscle can result in pain and swelling. Ice packs will help stop bleeding and reduce swelling.MUSCLE SPASM (cramp) – sustained contraction of the muscle, usually because of overuse.MYALGIA – muscle painTENDONITIS – inflammation of a tendon