Skeletal Muscle Anatomy
This contractile protein forms the thick filaments within a sarcomere.
What is myosin?
These muscle fibers are known as slow-twitch fibers and are highly resistant to fatigue.
What are type I muscle fibers?
This type of muscle action occurs when the muscle produces force while shortening.
What is a concentric contraction?
This molecule is the immediate source of energy for muscle contraction.
What is ATP (adenosine triphosphate)?
This rate-limiting enzyme breaks down phosphocreatine to rapidly regenerate ATP.
What is creatine kinase?
The basic functional unit of a myofibril is the region between these two structures.
What is the sarcomere between two z-discs.
Rank the muscle fiber types from greatest fatigue resistance to least fatigue resistance.
What is Type I → Type IIa → Type IIx?
Of the three muscle actions, this one generally allows the greatest force production.
What is an eccentric contraction?
This is the primary carbohydrate stored in skeletal muscle for energy production.
What is glycogen?
The end product of anaerobic glycolysis when oxygen is limited is this substance.
What is lactate?
This organelle surrounds myofibrils and serves as the primary storage site for calcium ions in skeletal muscle.
What is the sarcoplasmic reticulum?
This energy system is used predominantly by Type I fibers during prolonged exercise.
What is aerobic glycolysis (oxidative phosphorylation) ?
Holding a plank position primarily involves this type of muscle action.
What is an isometric contraction?
These are the main storage form of fat in adipose tissue.
What are triglycerides?
This organelle is the primary site of aerobic ATP production.
What are mitochondria?
This protein binds calcium, causing tropomyosin to move away from actin's binding sites.
What is troponin?
Most untrained individuals have approximately this percentage of Type I and Type II fibers.
What is about 50% Type I and 50% Type II fibers?
This relationship describes how muscle force changes as muscle length changes.
What is the length-tension relationship?
These are broken down into amino acids and can be used as an energy substrate during prolonged exercise.
What are proteins?
This final stage of aerobic metabolism produces the majority of ATP using oxygen.
What is the electron transport chain (oxidative phosphorylation)?
Damage to the T-tubules would most directly impair what muscle function?
What is the transmission of action potentials. Reducing contrations.
This laboratory technique is considered the gold standard for directly determining an individual's muscle fiber type composition.
What is a muscle biopsy?
This relationship describes how muscle force changes as the speed of contraction changes.
What is the force-velocity relationship?
As exercise intensity increases, reliance on this substrate increases most rapidly.
What is carbohydrate?
These two high-energy electron transporters are produced in the Krebs cycle and feed the electron transport chain.
What are NADH and FADH?