42 Questions
What is the primary function of skeletal muscle?
Voluntary movement
Which of the following is NOT a part of the excitation-contraction coupling process?
Glycolytic system
What is the role of Ryanodine receptors in muscle contraction?
Release of calcium ions
What is the purpose of the SarcoEndoplasmic Reticulum Calcium ATPase (SERCA)?
To pump calcium ions out of the muscle cell
What is the primary source of ATP for muscle contraction?
Phosphocreatine
What is the result of muscle fatigue?
Decreased muscle strength
Which type of muscle is responsible for involuntary movement?
Smooth muscle
What is the role of the Neuromuscular Junction (NMJ) in muscle contraction?
Transmission of action potential
What is the primary purpose of muscle cells?
To convert chemical energy into mechanical energy
What is the source of calcium for muscle contraction?
Intracellular storage
What is required for skeletal muscle contraction?
Depolarization and calcium release
Which type of muscle has a centrally located, cigar-shaped nucleus?
Skeletal muscle
What is the characteristic of skeletal muscle fibers?
Multinucleate and cylindrical
Which type of muscle is involuntary?
Cardiac muscle
What is the trigger for muscle contraction in all three types of muscle?
A rise in the free cytosolic calcium concentration
What is the characteristic of cardiac muscle fibers?
Striated with intercalated discs
What is the functional unit of a myofibril?
Sarcomere
What is composed of myofilaments?
Myofibril
What type of filaments are found in the I band?
Thin (actin) filaments
What is the center of the H-band?
M-line
What is the functional unit of the muscle cell?
Muscle fiber
What gives the striated appearance of skeletal and cardiac muscles?
Myofibril bands
What type of light does the A-band appear under the electron microscope?
Anisotropic
What is the portion of the myofibril that lies between two successive Z-disks?
Functional unit of the myofibril
What is the structure of filamentous actin (f-actin)?
Double helix
What is the function of tropomyosin?
Blocks actin binding sites
What is the function of troponin I?
Helps inhibit actin-myosin binding
What is the function of nebulin?
Regulates the length of the thin filament
What occurs when the head of myosin attaches to actin at the binding site?
Cross-bridge formation occurs
What is the function of titin?
Anchors myosin to Z disk
What is the function of troponin C?
Binds calcium ions
What is the largest protein found in the body?
Titin
What is the function of the alkali or 'essential light chains' in the myosin head?
Critical for ATPase activity
What is the role of the regulatory light chains in the myosin head?
Influence myosin-actin binding kinetics
What is the function of the Transverse (T) Tubules?
Transmit action potential to the terminal cisternae
What is the role of the Sarcoplasmic Reticulum?
Store Ca2+
What is the function of the terminal cisternae?
Connects with T-tubules via the sarcoplasmic reticulum
What is the result of the action potential moving down the sarcolemma from the synapse?
Transmission of action potential to the T-tubules
What is the role of the integrins in muscle contraction?
Usually used in cell signaling
What is the composition of the TRIAD?
Sarcoplasmic Reticulum + T-tubules
What is the function of the Desmin?
Other protein involved in muscle contraction
What is the result of the action potential transmitting to the terminal cisternae?
Release of Ca2+ from the sarcoplasmic reticulum
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