5Skeletal Muscle Attached to bone Striated (striped) appearance VOLUNTARYContract quickly, fatigue easily, can’t maintain contraction for long period of time
6Skeletal Muscles Each skeletal muscle cell contains many nuclei Muscle cells are known as muscle fibersCell membrane is call sarcolemmaCytoplasm is called sarcoplasm
7Smooth Muscle Visceral (organ) muscle Found 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
8Cardiac Muscle Found only in the heart Striated and branched InvoluntaryCells are fused – when one contracts, they all contract
9Sphincterspecial circular muscles in openings of esophagus and stomach, stomach and small intestine, anus, urethra and mouth.
10CHARACTERISTICS OF MUSCLES CONTRACTIBILITY – the ability of a muscle to reduce the distance between the parts of its contents or the space it surrounds.EXCITEABILITY (IRRITABILITY) – the ability to respond to certain stimuli by producing impulses.
11CHARACTERISTICS OF MUSCLES EXTENSIBILITY – the ability to be stretched.ELASTICITY – ability of muscle to return to its original length when relaxing.
12Naming Muscles Location: Size: Direction of fibers: frontalis-foreheadSize:gluteus maximusDirection of fibers:external abdominal obliqueNumber of origins:Biceps-two headed muscle in humerusLocation of origin and Insertion: sternocleidomastoid- origin in sternum
13Naming muscles Action flexor: Extensor: Levator and Depressor: flexor carpi ulnaris- flexes the wristExtensor:extensor carpi ulnaris- extends the wristLevator and Depressor:depressor anguli oris-depresses the corner of the mouth, raises or lowers body parts
14MOVEMENT Muscles 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. Rule: A muscle’s insertion bone moves toward its origin bone.Groups of muscles usually contract to produce a single movement.
15Sarcolemma: muscle cell membrane Muscle ContractionSarcolemma: muscle cell membraneSynaptic Cleft: gap between the axon and the muscle cell.
16Muscle ContractionMOTOR 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)
17MUSCLE 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.
18Muscle Efficiency Improves: -Coordination of all muscles involved -Respiratory and circulatory system to supply needs of active muscular system-Elimination of excess fat-Joint movement involved with that muscle activity
19Muscle StrengthStrength (capacity to do work) is increased with trainingMuscle size increase due to change in the sarcoplasm (cytoplasm found in the individual skeletal muscle fibers) Not the increase in the number of muscle fiber cells
20Tendons: non-elastic cords that attach muscles to bones Muscle AttachmentsTendons: non-elastic cords that attach muscles to bonesBones are connected at joints
21DIAPHRAGMDome-shaped muscle that separates the abdominal and thoracic cavities, aids in breathing
22Disorders and Related Terminology ATROPHY – wasting away of muscle due to lack of use.If we fail to exercise our muscles weaken and become flaccid ex. Quadriplegics, elderly on bedrest, extremity in a cast, etc.
23Massage of these muscles is essential in providing the proper physiotherapy or a general sense of comfort and well-being to a patient, also prevents atrophy in debilitated patients
24HYPERTROPHY – an increase in the size of the muscle cell. when over exercise the size of the muscle fibers increase due to a change in the sarcoplasm (not due to an increase in number of muscle fiber cells)
25STRAIN – tear in the muscle resulting from excessive use 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. RICE : rest, ice, compression, elevation
26Rehabilitation: retaining of injured or unused muscles MYALGIA – muscle pain