Diseases of the Muscular System
The disease described as inherited, caused by faulty genes for dystrophin, and often leads to progressive muscle weakness.
What is Muscular dystrophy
The three types of muscle tissue
What is Skeletal, Cardiac, & Smooth muscle tissue
The basic functional unit between two Z-lines.
What is the Sarcomere
The number of ATP molecules produced by cellular respiration when oxygen is available
What is 34
The name given to the muscle attachment on the more stationary bone?
The name given to the muscle attachment on the more movable bone?
What is Origin = more stationary bone;
What is Insertion = more movable bone.
This condition is believed to involve a change in nerve stimulation causing widespread musculoskeletal pain, fatigue, and sleep issues?
What is Fibromyalgia.
This muscle type is striated, branched, uninucleated, and involuntarily controlled
What is Cardiac muscle
The two myofilament proteins involved in the sliding filament model.
What are Actin and Myosin
How many ATP molecules are produced via anaerobic glycolysis/fermentation (when oxygen is NOT available),
What is 2 ATP
Define prime mover, synergist, and antagonist in the context of muscle pairs.
Prime mover = main contracting muscle; Synergist = helps the prime mover; Antagonist = opposes the action and relaxes during movement
Describe one cause and one symptom of Medial Tibial Stress Syndrome
Cause: Increased activity/microtears in connective tissue attaching muscles to tibia;
Symptom: tenderness, soreness, or pain along shin with mild swelling
Match each of the three membranes (epimysium, perimysium, endomysium) to what they cover.
Epimysium — covers whole muscle; Perimysium — covers a fascicle; Endomysium — covers an individual muscle fiber
Describe the role of myosin "heads" during contraction.
Myosin heads attach to actin active sites, pivot to pull actin toward the M-line, forming cross-bridges that shorten the sarcomere.
Define “oxygen debt”
The difference between oxygen available and oxygen required, experienced as being “out of breath”; after intense exercise, extra oxygen is needed to restore resting conditions.
Identify which is the prime mover and which is the antagonist during forearm flexion.
During forearm flexion: Biceps brachii = prime mover; Triceps brachii = antagonist
For muscular dystrophy, list two treatment approaches or management strategies.
What are: steroids; medicines to increase dystrophin; antiseizure drugs; immunosuppressants; physical therapy.
List and define the four characteristics common to all muscle tissues
Excitability (respond to stimulus), Contractility (shorten when stimulated), Extensibility (can be stretched), Elasticity (recoil to original shape)
Explain how calcium ions participate in the contraction cycle
Calcium exposes active sites on actin (by binding to troponin), allowing myosin heads to bind;
Explain the sequence of events during intense exercise that leads to muscle burning and fatigue
Sequence: (1) Intense exercise exhausts glucose; (2) ATP no longer efficiently used for cross-bridges (fatigue); (3) Muscles switch to anaerobic respiration causing burning sensation; (4) Oxygen debt occurs and breathing increases to repay it
Describe the hierarchical structural organization of a skeletal muscle from largest to smallest (use the terms: muscle, fascicle, muscle fiber, myofibril, myofilaments) and explain the protective membrane that surrounds an individual muscle fiber.
Hierarchy: Muscle -> Fascicle -> Muscle fiber (cell) -> Myofibril -> Myofilaments (actin & myosin). The endomysium surrounds an individual muscle fiber (protects fibers and allows sliding while preventing bursting).
Explain why aerobic capacity (oxygen availability) might influence susceptibility to muscular injury or cause muscular disease symptoms (pain/discomfort) during exercise.
When oxygen is limited, ATP production drops, so muscles fatigue more quickly and are more prone to damage during exertion; lactate threshold causes muscle fatigue (pain)
Compare and contrast skeletal and smooth muscle in terms of control (voluntary vs involuntary), appearance (striated vs nonstriated), typical contraction (quick, slow or both) and location.
Skeletal — voluntary, striated, can contract quickly or slowly, attached to bones;
Smooth — involuntary, nonstriated, slow sustained contractions, found in walls of internal organs.
Step-by-step: Outline the sliding filament theory cycle during a single contraction, including where ATP is used.
ATP energizes myosin head-> calcium exposes actin active sites -> myosin heads bind actin (cross-bridge forms) -> power stroke uses 1 ATP per cross-bridge cycle to move myosin head -> ATP converted into ADP + P to reset myosin head -> new ATP attaches to myosin head -> cycle repeats until stimulation ends and calcium is pumped back.
Discuss why a physically fit person is less likely to feel out of breath or sore after comparable exercise, referencing oxygen transfer and ATP production.
Fit individuals have more efficient cardiovascular and respiratory systems, delivering oxygen to muscles faster, supporting aerobic ATP production and reducing reliance on inefficient anaerobic pathways that cause fatigue and soreness.
Give three criteria used historically to name muscles (from the list in the notes) and provide an example muscle for each criterion.
Examples: Size (gluteus maximus — largest), Shape (deltoid — triangular like delta ∆), Location (pectoralis major — chest), Orientation (external obliques — fiber direction), Number of origins (biceps brachii — two origins), Function (adductor group — adducts thigh)