muscular system (2) Flashcards
What is the function of the muscular system?
Produce movement, maintain posture, stabilize joints, generate heat
What are the three basic muscle types?
Skeletal muscle, cardiac muscle, smooth muscle
What does ‘myo’ refer to?
Muscle
What does ‘mys’ refer to?
Muscle
What does ‘sacro’ refer to?
Flesh
What causes the contraction of muscles?
Movement of microfilaments
What type of control do skeletal muscles have?
Voluntary (subject to conscious control)
What is the connective tissue wrapping around a whole muscle called?
Perimysium
What is the connective tissue wrapping around a single muscle fiber called?
Endomysium
What is a fascicle?
A bundle of fibers
What covers the entire skeletal muscle?
Epimysium
What is the fascia?
Connective tissue on the outside of the epimysium
What are the sites of muscle attachment?
Bones, cartilages, and connective tissue coverings
What are the characteristics of smooth muscles?
No striations, spindle-shaped cells, single nucleus, involuntarily (no conscious control)
What does the epimysium blend into?
A connective tissue attachment (tendon or aponeurosis)
Where are smooth muscles found?
In the walls of hollow organs
What are the characteristics of cardiac muscle?
Striations, branching cells, single nucleus, involuntarily (no conscious control)
What is the microscopic anatomy of skeletal muscle?
Segment of muscle fiber, cells are multinucleate, nuclei are beneath sacrolemma
What is a sacrolemma?
Specialized plasma membrane
What is sacroplasmic reticulum?
Specialized smooth ER
What is a myofibril?
Bundles of myofilaments, aligned to give distinct bands
What is a sacromere?
Contractile unit of muscle fiber
What are the thick filaments composed of?
Myosin filaments; composed of protein myosin and has ATPase enzymes
What are the thin filaments composed of?
Actin filaments; composed of the protein actin
What are the properties of skeletal muscle activity?
Irritability (ability to receive and respond to a stimulus), contractility (ability to shorten and generate force)
What is the term for when an adequate stimulus is received?
Shortening
What stimulates skeletal muscles?
Nerve stimulus
What is a motor unit?
One neuron and the muscle cells it stimulates
Where do nerve and muscle associate?
Neuromuscular junctions
What is the gap between nerve and muscle called?
Synaptic cleft
