Muscle Physiology and Proprioception Lecture Notes R2

These flashcards review key concepts related to muscle physiology, contraction mechanisms, and proprioceptive feedback.

A relaxed sarcomere has __ overlap between actin and myosin.

not a lot of

In a contracted sarcomere, __ is more prominent between myosin and actin.

overlap

The myosin heads form a __ with actin during contraction.

cross bridge

Calcium ions bind to __, revealing the binding sites on actin.

troponin

The process of ATP being converted to ADP releases energy, allowing for the __ stroke.

power

In rigor mortis, the lack of __ prevents myosin from releasing actin, causing muscles to remain contracted.

ATP

The __ muscles are characterized by aerobic metabolism and endurance.

red

The __ muscle fibers are known for their rapid contraction and anaerobic metabolism.

white

Muscle spindle fibers and Golgi tendon organs contribute to __ in muscle movement.

proprioception

ADP remains attached to the myosin head during the __ phase of contraction.

cross bridge formation

The __ band shows the area of overlap between actin and myosin during contraction.

A

The myosin head pivots during the __ stage, contributing to a sliding motion.

power stroke

Calcium binding to troponin causes __ of tropomyosin, unblocking actin's binding sites.

shift

The Golgi tendon organ monitors __ in a muscle, providing feedback to the CNS.

tension

The muscle spindle fibers respond to __, providing information on muscle stretch.

stretch

During a muscle contraction, the myosin heads pull the actin filaments toward the __ line.

Z

The role of __ in muscle contraction is crucial for releasing the myosin head from actin.

ATP

The sliding filament hypothesis explains how actin and myosin __ during muscle contraction.

slide past one another

The absence of calcium ions allows the muscle to return to a __ state.

relaxed

The __ response involves adjusting the number of motor units recruited based on sensory feedback.

proprioceptive

Twitching of muscles due to excitation is primarily controlled by action potentials delivered via __.

motor neurons

Fast twitch fibers use __ primarily for energy, making them fatigue quickly.

glycolysis

The process of __ allows for improved oxygen delivery and ATP production in muscles.

increased mitochondrial density

The alpha motor neurons activate the muscle fibers, while __ neurons adjust sensitivity within the muscle spindle.

gamma

During a power stroke, ADP and __ are released from the myosin head.

inorganic phosphate

The myofilaments are organized into functional units called __ within a muscle fiber.

sarcomeres

The contraction of muscles is ultimately a result of the interaction between actin and __.

myosin

When performing endurance activities, favoring the recruitment of __ fibers can improve performance.

slow twitch

The combination of __ and troponin regulates the contraction process in skeletal muscle.

tropomyosin

The muscle fiber type that is suited for short bursts of power and speed is __.

fast twitch

Rapid contractions of fast twitch muscle fibers result from quick recycling of __ and rapid calcium reuptake.

actin-myosin cross bridges

The muscle spindle fibers are primarily involved in monitoring __ during muscle activity.

muscle length

Increased __ allows muscles to utilize oxygen more effectively, enhancing endurance.

capillary density

The __ reflex involves muscle spindle fibers detecting stretch and initiating a muscle contraction response.

stretch

Motor units consist of a single motor neuron and all the muscle fibers it innervates, enabling __ control over muscle contractions.

fine

Calcium is released from the __ reticulum to initiate muscle contractions.

sarcoplasmic

The interaction of the thick and thin filaments during contraction supports the __ hypothesis.

sliding filament

Skeletal muscle fibers contain multiple __ to facilitate high energy demands during contraction.

mitochondria

For a muscle to relax, calcium must be pumped back into the __.

sarcoplasmic reticulum

The phenomenon where one muscle group contracts while another is inhibited is known as __.

reciprocal inhibition

The contraction phase of muscle activity involves __ energy stored in ATP being converted into mechanical work.

chemical

During intense exertion, fast twitch fibers rely primarily on __ for energy production.

anaerobic metabolism

Muscle spindle fibers respond to __ by sending signals to the central nervous system.

changes in muscle length

The __ reflex prevents muscle injury by regulating the amount of tension placed on muscles and tendons.

Golgi tendon

The area where actin and myosin filaments overlap increases during __.

muscle contraction

Returning to resting length after contraction is primarily due to the __ of elastic components in the muscle.

recoil

Muscle type that demonstrates fatigue resistance and is rich in myoglobin is __ fiber.

red slow twitch

In muscles, __ refers to the tension generated during a contraction and varies by length.

force production

Tropomyosin acts as a regulatory __ that inhibits cross-bridge formation in muscles at rest.

protein

The __ step in cross-bridge cycling is when the ATP binds to myosin, causing it to release from actin.

detachment

Serum calcium levels and muscle contraction are inversely related, as a decrease in calcium causes __.

muscle relaxation

After death, the absence of ATP causes muscles to become rigid due to a sustained __ state.

contracted

The serine residue on troponin is phosphorylated to allow for __ and cross-bridge cycling.

calcium binding frequency

Proprioceptive feedback about the load on muscles prevents excessive tension potentially leading to __.

muscle injury

Skeletal muscle has unique fibers for rapid, high-intensity activities known as __ fibers.

Type II

Muscle hypertrophy is the result of increased __ in response to strength training.

muscle fiber size

Type I muscle fibers are also known as __ fibers due to their high endurance capabilities.

slow twitch

The primary role of __ is to facilitate movement by shortening the muscle fibers.

contraction

The __ structure allows for the organization and efficiency of muscle contraction.

sarcomere

To effectively generate power, muscle fibers rely on the availability of __ and oxygen.

ATP

The __ process includes both increasing the recruitment of fibers and the frequency of their activation.

tension generation

Stimulation of muscle comes from action potentials generated through the __ mechanism of motor neuron activation.

electrical

The unique mechanical characteristics of actin and myosin filaments are critical for enabling __ forces in muscle systems.

contractile