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Muslces Group 4. Classification  Agonist: prime mover  Antagonist: reverses agonist  Synergist: prevents rotation  Fixator: stabilizes the origin.

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Presentation on theme: "Muslces Group 4. Classification  Agonist: prime mover  Antagonist: reverses agonist  Synergist: prevents rotation  Fixator: stabilizes the origin."— Presentation transcript:

1 Muslces Group 4

2

3 Classification  Agonist: prime mover  Antagonist: reverses agonist  Synergist: prevents rotation  Fixator: stabilizes the origin of the prime mover

4 Naming (LADSNOR!)  Direction of the muscle fibers  Ex) transverse, rectus, oblique  Relative size of muscles  Ex) major, minor  Location  Number and location of origin  Shape  Action of the muscle  Ex) extensor, flexor

5 Origin and Insertion  Origin: immovable end  Insertion: movable end

6 Characteristics  Muscle cells are elongated  Contractions are due to the movement of microfilaments

7 Structure (skeletal muscle)

8 Structure (cont.)  From outermost to innermost  Muscle>Fascicles>Muscle fibers>Myofibril>Thick and thin filaments  Fascia>Epimysium>Perimysium>Endomysiu m

9 Tissue layers of a skeletal muscle  Fascia: covering the whole muscle  Epimysium: lies beneath the fascia  Perimysium: separates cells of fascicle  Endomysium: separates individual muscle fibers

10 Fascicle  Collection of muscle fibers  Covered by blood vessels and axon of motor neurons  Each muscle fibers is separated by endomysium  It is surrounded by sarcolemma  Contains nucleus and sarcoplasmic reticulum  Each muscle fibers is composed of myofibril

11 Myofibril & Sarcomere

12 Sarcomere  It is a repeating pattern formed by striations

13 Sarcomere (cont.)  Troponin: protein that works with tropomyosin to block muscle contraction until calcium ions are present  Transverse tubule: set of membranous channels that contain extracellular fluid

14 Smooth muscle  It is shorter than skeletal muscle, and has single centrally located nuclei  It lacks troponin  It alternates between a state of relaxation and contraction

15 Cardiac muscle  Composed of striated cells, containing a single nucleus  It has a well developed sarcoplasmic reticulum  Its transverse tubule is larger than skeletal muscle’s

16 Contraction  Acetylcholine(ACh) is the neurotransmitter that contracts skeletal muscles  ACh binds with receptors on the motor endplate, which causes muscle impulse  Calcium ions diffuse from sarcoplasmic reticulum to sarcoplasm and binds to troponin

17 Contraction (cont.)  Tropomyosin moves, which allows actin and myosin to link  Actin is pulled to the center of the sarcomere, which allows muscle fibers to shorten

18 Threshold

19 Respiration  Anaerobic breaks down glucose and releases ATP  Aerobic requires oxygen to produce ATP

20 Oxygen debt  When cellular respiration is not able to sustain the muscle, lactic acid diffuses into the blood stream  This creates an oxygen debt, that must be repaid later

21 Muscle fatigue  When a muscle loses its ability to contract  Most likely occurs from accumulation of lactic acid

22 Types of contraction


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