Muscle Contraction Flashcards
(20 cards)
What are the three types of muscle tissue?
Skeletal, cardiac, and smooth.
Which muscle type is voluntary and striated?
Skeletal muscle.
Which muscle type is involuntary and found in hollow organs?
Smooth muscle.
What is a sarcomere?
The basic contractile unit of muscle fiber.
What proteins form the thick and thin filaments in sarcomeres?
Myosin (thick) and actin (thin).
What triggers muscle contraction at the cellular level?
Depolarization of the sarcolemma leading to Ca2+ release.
What role does calcium play in muscle contraction?
Binds to troponin, allowing actin-myosin interaction.
What is the role of troponin in skeletal muscle?
It binds calcium and moves tropomyosin away from actin-binding sites.
What is the cross-bridge cycle?
The repeated formation and breaking of cross-bridges between actin and myosin.
What provides energy for muscle contraction?
ATP.
What neurotransmitter is released at the neuromuscular junction?
Acetylcholine (ACh).
What is the motor end plate?
The region of the muscle fiber membrane that interacts with the motor neuron.
What type of receptor binds acetylcholine at the NMJ?
Nicotinic cholinergic receptor.
What enzyme breaks down acetylcholine?
Acetylcholinesterase.
What causes muscle relaxation?
Removal of calcium ions and degradation of ACh.
What is rigor mortis and what causes it?
Post-death muscle stiffening due to lack of ATP to release myosin heads.
What is the function of the sarcoplasmic reticulum in muscle cells?
Stores and releases calcium ions.
What is the role of T-tubules in muscle fibers?
Transmit action potentials deep into the muscle fiber.
How is muscle contraction graded?
By recruitment of motor units and frequency of stimulation.
What is the difference between isotonic and isometric contraction?
Isotonic: muscle changes length; Isometric: muscle length stays the same.
