Muscle Physiology Vocabulary

Flashcards covering vocabulary terms related to muscle physiology, including muscle tissue types, properties, connective tissues, muscle fiber structure, proteins, contraction mechanisms, and pharmacology of the neuromuscular junction.

Skeletal muscle tissue

Primarily attached to bones. It is striated and voluntary.

Cardiac muscle tissue

Forms the wall of the heart. It is striated and involuntary.

Smooth muscle tissue

Located in viscera. It is nonstriated and involuntary.

Excitability

Ability to respond to chemicals released from nerve cells.

Conductivity

Ability to propagate electrical signals over membrane.

Contractility

Ability to shorten and generate force.

Extensibility

Ability to be stretched without damaging the tissue.

Elasticity

Ability to return to original shape after being stretched.

Epimysium

Surrounds the whole muscle (dense irregular CT).

Perimysium

Surrounds bundles (fascicles) of 10-100 muscle cells (looser areolar CT).

Endomysium

Separates individual muscle cells (loose areolar CT).

Tendon

Cord of dense connective tissue that attaches a muscle to the periosteum of a bone.

Aponeurosis

Tendon that extends as a broad, flat layer.

Sarcolemma

Muscle cell membrane.

Sarcoplasm

Filled with myofibrils & myoglobin (red-colored, oxygen-binding protein).

T tubules

Tiny invaginations of the sarcolemma that quickly spread the muscle action potential to all parts of the muscle fiber.

Sarcoplasmic reticulum

Releases calcium during muscular contraction.

Sarcomeres

Compartments separated by Z discs where thick and thin filaments overlap.

Myosin

Contractile protein found in thick filaments.

Actin

Contractile protein found n thin filaments.

Troponin and Tropomyosin

Regulatory proteins that turn contraction on and off.

Titin

Anchors thick filament to the M line and the Z disc; contributes to elasticity and extensibility.

Sliding Filament Mechanism

Myosin cross bridges pull on thin filaments, thin filaments slide inward, Z Discs come toward each other, Sarcomeres shorten.

Acetylcholine (ACh)

Neurotransmitter released at the neuromuscular junction.

Synaptic end bulbs

Swellings of axon terminals that contain synaptic vesicles filled with acetylcholine (ACh).

ATP hydrolysis

Splitting ATP to release energy to activate myosin heads.

Acetylcholinesterase (AChE)

Breaks down ACh within the synaptic cleft.

Botulinum toxin

Blocks release of neurotransmitter at the NMJ, causing muscle paralysis.

Curare

Plant poison that blocks ACh receptors, causing muscle paralysis.

Neostigmine

Anticholinesterase agent that strengthens weak muscle contractions.