Muscle Anatomy
What connective tissue surrounds the entire muscle?
Epimysium
What are the three types of muscle tissue?
Skeletal, cardiac, and smooth muscle
What is the plasma membrane of a muscle fiber called?
Sarcolemma
What neurotransmitter is released at the neuromuscular junction?
Acetylcholine (ACh)
What is a motor neuron plus all the muscle fibers it controls called?
Motor unit
What connective tissue surrounds a fascicle?
Perimysium
Which type of muscle is voluntary, striated, and attached to bones or skin?
Skeletal muscle
What is the cytoplasm of a muscle fiber called?
Sarcoplasm
What ion binds to troponin during skeletal muscle contraction?
Calcium (Ca²⁺)
Which skeletal muscle fiber type is highly resistant to fatigue and suited for endurance activities?
Slow oxidative fibers
What connective tissue surrounds each individual muscle fiber?
Endomysium
Which muscle tissue is found only in the heart?
Cardiac muscle
What is the smallest functional contractile unit of a muscle fiber?
Sarcomere
When calcium binds troponin, what protein moves away and exposes the myosin-binding sites on actin?
Tropomyosin
Which fiber type is best suited for short, intense, powerful movements?
Fast glycolytic fibers
What is a bundle of muscle fibers called?
Fascicle
What four characteristics are shared by all muscle tissue?
Excitability, contractility, extensibility, and elasticity
A sarcomere extends from one _____ to the next.
Z disc
What are the four major steps leading to skeletal muscle contraction?
Events at NMJ → muscle fiber excitation → excitation-contraction coupling → cross-bridge cycling
What happens to skeletal muscle during resistance exercise such as weightlifting?
Muscle hypertrophy
Put these in order from largest to smallest: muscle fiber, muscle, myofibril, fascicle.
Muscle → fascicle → muscle fiber → myofibril
Name the four major functions of muscle tissue
Produce movement, maintain posture/body position, stabilize joints, and generate heat
Which filament is thin, and which is thick?
Actin = thin; myosin = thick
During contraction, what structure releases Ca²⁺ into the muscle fiber?
Sarcoplasmic reticulum (SR)
Why does rigor mortis occur after death?
ATP is no longer produced, so Ca²⁺ cannot be pumped back into the SR and cross-bridges cannot detach.