Ch 9 & 10 Vocab Flashcards
Contraction
The process where muscles shorten and generate force.
Sarcomere
The basic unit of a muscle, made up of actin and myosin, responsible for contraction.
Sarcolemma
The membrane surrounding a muscle fiber.
Sarcoplasmic Reticulum
A structure that stores calcium ions, which are crucial for muscle contraction.
Sarcoplasm
The cytoplasm of a muscle cell, containing nutrients and organelles.
Muscle Fiber
A single muscle cell, capable of contraction.
Myoblast
An immature muscle cell that can develop into a muscle fiber.
Myofibril
A long, thread-like structure within a muscle fiber, made up of sarcomeres.
Myofilament
The filaments (actin and myosin) that make up myofibrils and are responsible for muscle contraction.
Fascicle
A bundle of muscle fibers grouped together.
Tendon
The connective tissue that attaches muscle to bone.
Endomysium
The thin layer of connective tissue that surrounds individual muscle fibers.
Perimysium
The connective tissue that surrounds a fascicle of muscle fibers.
Epimysium
The outer layer of connective tissue that surrounds the entire muscle.
Actin
A protein that forms thin filaments in muscle fibers and plays a key role in contraction.
Myosin
A protein that forms thick filaments in muscle fibers and interacts with actin to produce contraction.
Myosin Heads
Projections on myosin that attach to actin during contraction.
Cross-Bridges
Connections formed between myosin heads and actin during contraction.
Neuromuscular Junction
The site where a motor neuron communicates with a muscle fiber.
Motor End Plate
The part of the muscle fiber membrane that receives signals from the neuron.
Acetylcholine
A neurotransmitter released at the neuromuscular junction to trigger muscle contraction.
Troponin
A protein that helps regulate muscle contraction by binding calcium ions.
Tropomyosin
A protein that blocks actin sites for myosin, preventing contraction until calcium is present.
Calcium Ions
Ions that, when released from the sarcoplasmic reticulum, trigger muscle contraction.
Sliding Filament Theory
The explanation of how muscles contract by the sliding of actin over myosin.
Membrane Potential
The electrical charge difference across a cell membrane.
Transverse Tubules
Extensions of the sarcolemma that help transmit electrical signals into the muscle fiber.
Triads
Structures formed by a transverse tubule and two adjacent sarcoplasmic reticulum sacs, important for muscle contraction.
Depolarization
The process of a muscle cell’s membrane potential becoming less negative, leading to contraction.
Repolarization
The return of the membrane potential to its resting state after contraction.
Hyperpolarization
When the membrane potential becomes more negative than the resting state
Isotonic
Muscle contractions where the muscle changes length (shortens or lengthens) while generating force.
Isometric
Muscle contractions where the muscle generates force without changing length.
Tetanus
A sustained muscle contraction due to rapid stimulation.
Motor Unit
A single motor neuron and all the muscle fibers it controls.
Recruitment
The process of activating more motor units to increase muscle force.
Fast Fibers
Muscle fibers that contract quickly but tire out fast; good for short bursts of strength.
Slow Fibers
Muscle fibers that contract slowly but are more resistant to fatigue; good for endurance activities.
Cori Cycle
The process where lactate produced in muscles is converted back to glucose in the liver.
Appendicular muscle
those in the limbs
Axial Muscle
are in the trunk and head
