Ansphy

    Cards (105)

    • What are the main functions of the muscular system?
      • Movement
      • Maintain posture
      • Respiration
      • Production of body heat
      • Communication
      • Heartbeat
      • Contraction of organs
    • What type of muscle is found in the heart?
      Cardiac Muscle
    • What are the characteristics of cardiac muscle?
      Striated, involuntary, and nucleus is central
    • Where is smooth muscle found?
      In the walls of visceral organs
    • What are the characteristics of smooth muscle?
      Involuntary, striated, and nucleus is central
    • What type of muscle is associated with the skeletal system?
      Skeletal Muscle
    • What are the characteristics of skeletal muscle?
      Striated, voluntary, attached to bones
    • What are the abilities of skeletal muscles?
      • Contractility: Ability to shorten
      • Excitability: Respond to stimulus
      • Extensibility: Can stretch
      • Elasticity: Recoil
    • What percentage of body weight do skeletal muscles make up?
      40%
    • What is the connective tissue that surrounds each muscle fiber called?
      Endomysium
    • What are the connective tissue coverings of skeletal muscle?
      • Epimysium: Surrounds entire skeletal muscle
      • Perimysium: Surrounds each muscle fasciculus
      • Endomysium: Surrounds each muscle fiber
    • What is the structure of a muscle fiber?
      Myofibril
    • What is the function of the sarcoplasmic reticulum?
      Stores and releases Ca2+^{2+} for contractility
    • What are the two types of filaments in skeletal muscle?
      Actin and Myosin
    • What is the role of troponin in muscle contraction?
      It is the attachment site on actin for Ca2+^{2+}
    • What is the role of tropomyosin in muscle contraction?
      It is a filament on grooves of actin that blocks myosin binding sites
    • What are the components of a sarcomere?
      • Z-disk: Attachment site for actin
      • H zone: Center of sarcomere with only myosin
      • I-band: Contains only actin
      • A-band: Where actin and myosin overlap
      • M line: Where myosin are anchored
    • What is the resting membrane potential inside a muscle cell?
      Negative charge due to K+^{+} ions
    • Why is the inside of a cell negative if K+^{+} is positive?

      K+^{+} can diffuse out freely while larger negative molecules cannot
    • What happens during depolarization?
      The inside of the cell becomes more positive and the outside more negative
    • What are the steps of muscle contraction according to the sliding filament theory?
      1. Action potential travels down the motor neuron.
      2. Ca2+^{2+} channels open, releasing acetylcholine.
      3. Acetylcholine binds to Na+^{+} channels, causing depolarization.
      4. Na+^{+} increases permeability of sarcoplasmic reticulum.
      5. Ca2+^{2+} binds to troponin, exposing myosin binding sites.
      6. Myosin heads bind to actin.
      7. ATP is released, causing myosin heads to bend.
      8. Actin slides over myosin.
      9. Acetylcholinesterase breaks down acetylcholine, stopping contraction.
    • What is the role of ATP in muscle contractions?
      ATP supplies energy and helps form cross-bridge formation between myosin and actin
    • What happens to ATP during muscle contractions?
      ATP is released as ADP + P
    • What is rigor mortis?
      It occurs when no ATP is available to release muscle contraction after death
    • What are the characteristics of slow twitch fibers?
      • Contract slowly
      • Fatigue slowly
      • Use aerobic respiration
      • Energy from fat
      • Dark meat due to myoglobin
    • What are the characteristics of fast twitch fibers?
      • Contract quickly
      • Fatigue quickly
      • Use anaerobic respiration
      • Found in sprinters
    • What type of respiration do slow twitch fibers use?
      Aerobic respiration
    • What type of respiration do fast twitch fibers use?
      Anaerobic respiration
    • Why are slow twitch fibers red or dark in color?
      Due to the presence of myoglobin
    • What is the primary energy source for slow twitch fibers?
      Fat
    • What is the primary energy source for fast twitch fibers?
      Glucose
    • What is the main difference between slow and fast twitch fibers?
      Slow twitch fibers contract slowly and fatigue slowly, while fast twitch fibers contract quickly and fatigue quickly
    • How do slow twitch fibers contribute to endurance activities?
      They provide sustained energy through aerobic respiration
    • How do fast twitch fibers contribute to sprinting activities?
      They provide quick bursts of energy through anaerobic respiration
    • What is the significance of myoglobin in muscle fibers?
      • Helps bind oxygen in muscle
      • Important for aerobic respiration
      • Contributes to the red or dark color of slow twitch fibers
    • Compare the characteristics of slow twitch and fast twitch fibers.
      Slow Twitch Fibers:
      • Contract slowly
      • Fatigue slowly
      • Use aerobic respiration
      • Dark meat due to myoglobin

      Fast Twitch Fibers:
      • Contract quickly
      • Fatigue quickly
      • Use anaerobic respiration
      • Light meat due to less myoglobin
    • What is the role of bending forces in muscle contraction?
      Bending forces cause actin to slide over myosin.
    • What is the function of acetylcholinesterase in muscle contraction?
      It breaks down acetylcholine, leading to the closure of Na+ channels and stopping muscle contraction.
    • What is the process of ATP production and its role in muscle contractions?
      • Energy for muscle contractions is supplied by ATP.
      • Energy is released as ATP converts to ADP + P.
      • ATP is stored in myosin heads.
      • ATP is necessary for cross-bridge formation between myosin and actin.
      • New ATP must bind to myosin to release the cross-bridge.
    • What happens to muscles after death due to lack of ATP?
      Rigor mortis occurs, causing muscles to harden.
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