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Muslces Group 4.

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Presentation on theme: "Muslces Group 4."— Presentation transcript:

1 Muslces Group 4


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>Endomysium

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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