Life 48- Musculoskeletal Systems Flashcards
T tubules
A system of tubules that runs throughout the cytoplasm of a muscle fibre, through which action potentials spread
Cancellous bone
A type of bone with numerous internal cavities that make it appear spongy, although it is rigid
Actin
A protein that makes up the cytoskeletal microfilaments in eukaryotic cells and is one of the two contractile proteins in muscle
Extensor
A muscle that extends an appendage
Ligament
A band of connective tissue linking two bones in a joint
Tropomyosin
One of the three protein components of an actin filament; controls the interactions of actin and myosin necessary for muscle contraction
Muscle fibre
A single muscle cell. In the case of skeletal muscle, a syncytial multinucleate cell.
Sliding filament theory
Mechanism of muscle contraction based on the formation and breaking cross ridges between actin and myosin filaments, causing the filaments to slide together.
Endoskeleton
An internal skeleton covered by other, soft body tissues.
Skeletal systems
Organ systems that provide rigid supports against which muscles can pull to create directed movements.
Tetanus
A state of sustained maximal muscular contraction caused by rapidly repeated stimulation.
Cartilage bone
A type of bone that begins its development as a cartilaginous structure resembling the future mature bone, then gradually hardens into mature bone.
Membranous bone
A type of bone that develops by forming on a scaffold of connective tissue
Bone
A rigid component of vertebrate skeletal systems that contains an extracellular matrix of insoluble calcium phosphate crystals as well as collagen fibres
Osteoclast
A cell that dissolves bone
Joint
In skeletal systems, a junction between two or more bones
Osteoblast
A cell that lays down the protein matrix of bone.
Motor unit
A motor neuron and the muscle fibres it controls
Osteocyte
An osteoclast that has become enclosed in lacunae within the bone it has built
Fast-twitch fibres
Skeletal muscle fibres that can generate high tension rapidly, but fatigue rapidly (“sprinter” fibres). Characterised by an abundance of enzymes of glycolysis
Tendon
A collagen-containing band of tissue that connects a muscle with a bone.
Myofibril
A polymeric unit of actin or myosin in a muscle
Myoglobin
An oxygen-binding molecule found in muscle. Consists of a heme unit and a single globin chain; carries less oxygen than hemoglobin
Sarcomere
The contractile unit of a skeletal muscle
Hydrostatic skeleton
A fluid-filled body cavity that transfers forces from one part of the body to another when acted on by surrounding muscles
Smooth muscle
Muscle tissue consisting of sheets of mononucleated cells innervated by the autonomic nervous system
Myosin
One of the two contractile proteins of muscle
Cartilage
In vertebrates, a though connective tissue found in joints, the outer ear, and elsewhere. Forms the entire skeleton in som animal groups.
Skeletal muscle
A type of muscle tissue characterised by multinucleated cells containing highly ordered arrangements of actin and myosin microfilaments
Compact bone
A type of bone with a solid, hard structure
Troponin
One of the three components of an actin filament; binds to actin, tropomyosin, and Ca2+
Titin
A protein that holds bundles of myosin filaments in a centred position within the sarcomeres of muscle cells. The largest protein in the human body.
Sarcoplasmic reticulum
The endoplasmic reticulum of a muscle cell
Flexor
A muscle that flexes an appendage
Sarcoplasm
The cytoplasm of a muscle cell
Cardiac muscle
A type of muscle tissue that makes up, and is responsible for the beating of, the heart. Characterised by branching cells with single nuclei and a striated (striped) appearance.
Slow-twitch fibres
Skeletal muscle fibres that generate tension slowly, but are resistant to fatigue (“marathon” fibres). They have abundant mitochondria, enzymes of aerobic metabolism, myoglobin, and blood supply.
Twitch
A single unit of muscle contraction
Haversian systems
Units of organisation in compact bone that reflect the action of intercommunicating osteoblasts.
