Muscular System Flashcards
Actin
A protein that forms microfilaments and is found in the cytoskeleton, the myofibrils of muscle fibers, and in spindle fibers during cell division
Actin Filaments
Formed by one of the 2 contractile proteins of muscle (the other is myosin) that slide over each other to produce the shortening of the muscle cell during muscle contraction
Smooth Muscle
Mononucleated, nonstriated, involuntary muscle that is found in soft internal organs and structures
Skeletal Muscle
Multinucleated, striated, voluntary muscle that enable conscious movement and moves the bones of the skeleton
Skeletal Muscle Fiber
Skeletal muscle cell that has a long, thin, fiber-like appearance
Striated
Meaning striped
Striated Muscle
Muscle that looks striped due to alternating light and dark bands
Voluntary Muscle
Skeletal muscle
Voluntary striated muscle
Skeletal muscle
Nonstriated Involuntary Muscle
Smooth muscle
Myosin
Protein present in muscle fibers that aids in muscle contraction and makes up the majority of muscle protein
Myosin Filaments
One of two contractile proteins of muscle (the other is actin) that slide over each other to cause muscle contraction
Muscle Tissue
Collection of tissues that support the body, enable it to move, thermoregulate, and transport materials
Involuntary striated muscle
Cardiac muscle
Involuntary muscle
Smooth muscle
Fascia
Arrangement of dense regular connective tissue that lies over muscle and helps to support, separate, and connect muscle to other structures
Diaphragm
- Thin, dome-shapes sheet of muscle that forms the boundary between the thoracic and abdominal cavities and helps produce inspiration when it contracts
- It is dome-shaped at rest with the convex surface directed cranially. The dome flattens when contracted, which causes air to be drawn into the lungs by increasing the volume of the thoracic cavity
Cardiac Muscle
Striated involuntary muscle found only in the heart, that is influenced by the autonomic nervous system, and that has one centrally located nucleus and intercalated discs that form special connections between the muscle branches
Belly
Thick central portion of a muscle
Adenosine diphosphate (ADP)
‘Discharged’ form of ATP that contains 2 phosphoric acid groups.
Adenosine triphosphate (ATP)
- High-energy molecule produced in mitochondria
- A nucleotide that contains 3 phosphoric acid groups
- Energy is released when one phosphoric acid group breaks off and produces ADP
Aerobic Metabolism
- “Oxygen-consuming metabolism”
- Type of metabolism in muscle in which the supply of available O2 is sufficient to keep up with the energy needs of the muscle fibers
- Extracts the maximum amount of energy from glucose molecules
Anaerobic Metabolism
- “Non-oxygen-dependent metabolism”
- Type of metabolism in muscle that occurs when the need for energy exceeds the available O2 supply.
- Not as efficient as aerobic metabolism
- Forms lactic acid, which can cause discomfort in the muscle tissue and requires O2 for conversion back to glucose
Antagonist
Muscle or muscle group that directly opposed the action of a prime mover muscle that is directly producing a desired movement
Aponeurosis
Broad sheet of fibrous connective tissue that attaches certain muscles to bones or other muscles
Creatinine Phosphate
Molecule in muscle cells that splits to release the energy necessary to reattach the detached phosphate group to an ADP molecule to convert it back to ATP
Cross-bridges
Tiny levers on myosin filaments that ratchet back and forth to pull actin filaments toward the center of the myosin filaments
Dense Bodies
- Structure in smooth muscle cells to which small contractile units of actin and myosin attach
- Correspond to Z discs of skeletal muscle
Endomesium
Thin, delicate layer of connective tissue that surrounds each individual skeletal muscle fiber
Epimysium
Tough, connective tissue layer that covers and delineates individual muscles and surrounds groups of skeletal muscle fascicles
Expiratory Muscle
A muscle whose action is to decrease the size of the thoracic cavity to squeeze air out of the lungs
Fascicle
Group of skeletal muscle fibers bound together by the perimysium
Fixator
Muscle that stabilizes a joint so that other muscles can produce effective movements of other joints
I Band
- Large, light bands in a skeletal muscle fiber that alternate with darker A bands to give a striated appearance
- Composed of actin filaments