Skeletal Muscle Fiber Types Quiz

<p>Shortening requires overlapping actin and myosin (C)</p> Signup and view all the answers

<p>Reduced number of accessible cross bridges (D)</p> Signup and view all the answers

<p>Type I (B)</p> Signup and view all the answers

<p>Fast-glycolytic (C)</p> Signup and view all the answers

<p>Increased resistance to fatigue (A)</p> Signup and view all the answers

<p>Large amounts of mitochondria (C)</p> Signup and view all the answers

<p>They have a higher myosin-ATPase activity. (C)</p> Signup and view all the answers

<p>Type IIa (B)</p> Signup and view all the answers

<p>Glycolytic fibres primarily rely on anaerobic respiration. (C)</p> Signup and view all the answers

<p>They are primarily designed for high-intensity, short-duration activities. (C)</p> Signup and view all the answers

<p>Load remains constant (C)</p> Signup and view all the answers

<p>Isometric contraction (C)</p> Signup and view all the answers

<p>Isokinetic contraction (C)</p> Signup and view all the answers

<p>Eccentric contractions lengthen the muscle under load. (B)</p> Signup and view all the answers

<p>Greater likelihood of muscle damage occurs. (A)</p> Signup and view all the answers

<p>Some skeletal muscles can produce movement without an insertion. (A)</p> Signup and view all the answers

<p>Isokinetic contraction (A)</p> Signup and view all the answers

<p>During isometric contractions (D)</p> Signup and view all the answers

<p>They convey information about muscle length. (B)</p> Signup and view all the answers

<p>They cause contraction of intrafusal muscle fibers. (D)</p> Signup and view all the answers

<p>To convey information regarding muscle tension. (D)</p> Signup and view all the answers

<p>They send signals to the central nervous system when detecting stretch. (B)</p> Signup and view all the answers

<p>Contributing to muscle spindle sensitivity. (B)</p> Signup and view all the answers

<p>Muscle length. (A)</p> Signup and view all the answers

<p>Alpha motor neurons. (D)</p> Signup and view all the answers

<p>Contraction of intrafusal fibers. (A)</p> Signup and view all the answers

<p>Relative position and movement of the body. (D)</p> Signup and view all the answers

<p>Central pattern generators. (B)</p> Signup and view all the answers

<p>They detect changes in muscle length. (A)</p> Signup and view all the answers

<p>Monosynaptic. (B)</p> Signup and view all the answers

<p>Flexion of the affected limb. (C)</p> Signup and view all the answers

<p>They transmit sensory information to the CNS. (B)</p> Signup and view all the answers

<p>To maintain balance during withdrawal. (B)</p> Signup and view all the answers

<p>Extensor muscles of the knee. (D)</p> Signup and view all the answers

<p>Pain and discomfort in a limb. (C)</p> Signup and view all the answers

<p>Muscles that cause movement. (C)</p> Signup and view all the answers

<p>To transmit information to the muscle. (A)</p> Signup and view all the answers

<p>Involuntary reflex pathways. (A)</p> Signup and view all the answers

<p>Genetic endowment and activity level (C)</p> Signup and view all the answers

<p>High-intensity training and increased muscle fiber size (B)</p> Signup and view all the answers

<p>High levels of testosterone (C)</p> Signup and view all the answers

<p>By pulling of actin filaments by myosin within sarcomeres (A)</p> Signup and view all the answers

<p>They function as levers that pivot at joints. (A)</p> Signup and view all the answers

<p>Tension is first generated in the muscle fibers. (C)</p> Signup and view all the answers

<p>Closer insertion points increase the force required to lift a load. (C)</p> Signup and view all the answers

<p>Muscle endurance training (A)</p> Signup and view all the answers

<p>Transmission of force to the bones (A)</p> Signup and view all the answers

<p>Muscle fibers adapt to specific training regimes. (D)</p> Signup and view all the answers

<p>Skeletal muscles only pull bones to create movement. (C)</p> Signup and view all the answers

<p>To connect muscle fibers to bones. (B)</p> Signup and view all the answers

<p>Increased muscle fiber size and strength (A)</p> Signup and view all the answers

<p>The lever system (A)</p> Signup and view all the answers

Slow-twitch fibers that rely on aerobic pathways for energy production; have high mitochondria, capillary, and myoglobin content, resisting fatigue.

Fast-twitch fibers that use both aerobic and anaerobic pathways for energy; possess moderate mitochondria and myoglobin content, and are moderately resistant to fatigue.

Fast-twitch fibers that rely primarily on anaerobic glycolysis for energy; have high enzyme levels for rapid energy production but fatigue quickly.

Energy production using oxygen, creating more ATP than anaerobic methods, allowing for longer activities.

Energy production without oxygen; creates ATP quickly but less efficiently, leading to fatigue.

The rate at which myosin hydrolyzes ATP, impacting the speed of cross-bridge cycling and muscle contraction.

The decline in muscle power output due to sustained or intense exercise, often linked to energy depletion or metabolic factors.

Muscle fibers categorized based on their primary energy production method, impacting their endurance and fatigue resistance.

Muscle contraction where muscle length changes while tension remains constant. This is the most common type of contraction used in daily activities.

Muscle contraction where muscle length remains constant while tension increases. No visible movement is observed.

Muscle contraction where the speed of movement remains constant, regardless of the load.

Muscle contraction where the muscle lengthens under load. This occurs when resisting gravity or slowing down a movement.

Muscle contraction where the muscle shortens under load. This is the most common type of contraction used in activities like lifting.

Damage to muscle fibers caused by intense or unaccustomed exercise, primarily during eccentric contractions.

Eccentric contractions involve more stress on muscle fibers, leading to greater damage compared to concentric or isometric contractions.

Load refers to the resistance against which a muscle contracts. It affects the type of contraction and the amount of force required.

The ideal length for a muscle to generate maximum force is where there is optimal overlap between actin and myosin filaments. This allows for the maximum number of cross-bridges to form and efficiently pull the actin filaments.

If a muscle is too short, the actin filaments overlap excessively, leading to inefficient force production. Cross-bridges cannot form optimally, resulting in a weaker contraction.

When a muscle is too stretched, the actin and myosin filaments are too far apart, resulting in fewer cross-bridge formations and a weak contraction. The muscle can't generate much tension.

The ideal length of a muscle fiber for maximum force generation is when there is a sufficient overlap of actin and myosin filaments. This allows for many cross-bridges to form and exert strong pulling forces.

Muscle fatigue can be caused by either excessive use of the muscle or a lack of use. Extreme use can lead to energy depletion and metabolite buildup, while disuse can result in muscle atrophy and weakness.

The percentage of each muscle fiber type is largely determined by genes and partly by activity.

Muscle fibers adapt to demands like increased oxidative capacity (aerobic endurance) or hypertrophy (increased size).

The ability of muscles to use oxygen efficiently.

Increase in muscle fiber size due to high-intensity training.

Testosterone promotes the synthesis and assembly of active myosin in muscle.

Muscle fiber types can transform (change) with proper exercise.

Whole muscles are bundles of muscle fibers attached to bones by tendons.

Muscle contractions pull on bones to create movement. Tension is first generated internally within sarcomeres.

Bones act as levers, joints as fulcrums, and muscles provide force. This system amplifies velocity and distance.

The pivot point of a lever system. E.g., a joint is a fulcrum in the body.

Tension produced within muscle fibers is transmitted through tendons to bones, leading to movement.

The attachment point of the muscle closer to a joint influences the force needed to move a load.

High intensity exercise leads to increase in overall muscle size by increasing muscle fiber size (cross-sectional area).

Neural circuits in the spinal cord that produce rhythmic patterns of muscle activity, like walking, without conscious effort.

Sensory information carried from the body to the central nervous system (brain and spinal cord).

The sense of body position and movement, allowing us to understand where our body parts are in space.

Sensory receptors within muscles that detect changes in muscle length.

Specialized muscle fibers within muscle spindles that detect stretch and send signals to the central nervous system.

Regular muscle fibers that are responsible for generating force and movement.

Nerve cells that stimulate the contraction of extrafusal muscle fibers.

Nerve cells that control the tension within intrafusal fibers, ensuring accurate length sensing.

Sensory receptors located in tendons that detect changes in muscle tension.

Simultaneous activation of alpha and gamma motor neurons, ensuring muscle spindle sensitivity during contraction.

Specialized sensory receptors found within muscles that detect changes in muscle length (stretch) and rate of change.

Muscle spindles detect muscle stretch, transmitting signals to the spinal cord via sensory neurons, triggering an involuntary muscle contraction to resist further stretching.

A reflex pathway involving only one synapse between the sensory neuron and the motor neuron, resulting in a rapid and direct response.

By detecting and resisting sudden stretches, the stretch reflex protects muscles from overstretching and potential injury.

A reflex triggered by a painful stimulus, causing an involuntary withdrawal of the affected body part.

Agonistic muscles contract to create movement, while antagonistic muscles relax to allow for the movement. This coordinated action allows for effective withdrawal.

A reflex that occurs simultaneously with the withdrawal reflex, where the opposite limb extends to maintain balance and support the body.

By extending the opposite limb, the crossed extensor reflex helps to maintain balance and prevent falling during withdrawal reflexes.

The three main types of reflexes are: the stretch reflex (muscle stretch), the withdrawal reflex (painful stimulus), and the crossed extensor reflex (balance during withdrawal) .

Reflexes are critical for survival, protecting the body from harm by triggering rapid, involuntary responses to stimuli.