Chapter 11- Musculoskeletal System Flashcards
Skeletal muscle
Involved in support and movement. Propulsion of blood in the Venus system.
Thermal regulation.
Striated.
Under voluntary or somatic control. Polynucleated.
What are the two types of fibers in skeletal muscle?
Slow twitch fibers that carry out oxidative phosphorylation. White fast twitch fibers that rely on anaerobic metabolism.
Myoglobin
An oxygen carrier that uses iron in a heme group to bind oxygen. Present in slow and fast twitch fibers. More numerous in slow twitch fibers.
Smooth muscle
Present in the respiratory reproductive cardiovascular and digestive systems. Non-striated.
Under involuntary or autonomic control.
Uninucleated.
Can display myogenic activity (contraction without neural input)
Cardiac muscle
The contractile tissue of the heart. Striated.
Under involuntary or autonomic control.
Uninucleated,sometimes binucleated. Can display myogenic activity (contraction without neural input). Cells are connected with intercalated discs that contain a gap junctions. (Allows for full of ions directly between cells it allows for rapid uncoordinated depolarization of muscle cells)
Sarcomere
The basic contractile units of striated muscle. Contains thick myosin and thin actin filaments.
What are the bodyguards of actin filaments?
Troponins and tropomyosin that both are found on the thin filament of actin
M line of the sarcomere
Located in the middle of the sarcomere
I – band of the sarcomere
Contains only thin filaments
H zone of the sarcomere
Consists of only thick filaments
A band of the sarcomere
Contains thick filaments in their entirety. The only part of the sarcomere that does not change size during contraction.
Myocyte
Muscle cell/muscle fiber
Sarcomeres attach end to end to become what?
Myofibril. Each muscle cell or muscle fiber contains many myofibrils.
What surrounds myofibrils?
Sarcoplasmic reticulum And sarcolemma
Sarcoplasmic reticulum
A calcium containing modified endoplasmic reticulum.
A network of specialized smooth endoplasmic reticulum and transmits the electrical impulse as well as the storage of calcium ions.
Sarcolemma
Cell membrane of a myocytes or muscle cells/muscle fiber
T tubules transverse tubules
Allows for distribution of the action potential to all sarcomeres in a muscle. Oriented perpendicularly to myofibrils
Where does muscle contraction begin?
The neuromuscular junction.
Neuromuscular junction
Where the motor neuron releases acetylcholine that binds to receptors on the sarcolemma causing depolarization.
What causes depolarization in the musculoskeletal system?
Release of acetylcholine that binds to receptors on the sarcolemma 
Depolarization and muscle cells leads to what action?
Depolarization spreads down the sarcolemma to the T tubules and triggers release of calcium ions.