Musculoskeletal System Flashcards
Explain the function of the musculoskeletal system
Enables movement, supports the body, and maintains posture using bones, muscles, tendons, ligaments, and connective tissue.
Describe the three types of muscle
Skeletal Muscle: Striated, voluntary, attaches to bones for movement.
Smooth Muscle: Non-striated, involuntary, lines organs for processes like digestion.
Cardiac Muscle: Striated, involuntary, found only in the heart, contracts rhythmically.
What are skeletal muscles?
Voluntary, striated muscles attached to bones by tendons; responsible for movements like walking or lifting.
What are smooth muscles?
Involuntary, non-striated muscles in organs, regulating processes like blood flow and digestion.
What are cardiac muscles?
Striated muscles in the heart, working involuntarily for rhythmic contractions.
Explain the sliding filament theory and muscle contraction
Actin and myosin filaments slide past each other, shortening the sarcomere to produce contraction, powered by ATP.
What is the role of ATP in muscle contraction
ATP breaks actin-myosin cross-bridges and recocks myosin heads for repeated contractions.
Define sarcomere and its function
The functional unit of muscle contraction, containing actin and myosin filaments.
What is the neuromuscular junction? (NMJ)
The synapse where a motor neuron transmits action potential to a muscle fibre via acetylcholine.
List the components of the skeletal system
Bones, joints, cartilage, ligaments, tendons.
What are the three types of joints?
Fibrous Joints: Immovable, e.g., skull.
Cartilaginous Joints: Slightly movable, e.g., ribs.
Synovial Joints: Freely movable, e.g., hip.
describe the role of ligaments and tendons
Ligaments: Connect bones to bones, stabilizing joints.
Tendons: Connect muscles to bones, transmitting force for movement.
explain antagonist pairs of muscles
One muscle (agonist) contracts while the other (antagonist) relaxes to create smooth, controlled movement.
What are the functions of the musculoskeletal system?
Movement coordination.
Support and structure.
Blood cell production in red bone marrow.
Mineral storage (calcium and phosphate).
Why is calcium important in bones?
It aids nerve conduction, muscle contraction, and blood clotting.
Why is phosphate important in bones?
It is essential for DNA structure and energy metabolism.
describe how skeletal muscle appears under a microscope
Striated with alternating light (I bands) and dark (A bands) due to organized actin and myosin in sarcomeres.
Explain the cross-bridge cycle during muscle contraction
Myosin binds to actin, forming a cross-bridge.
Power stroke pulls actin towards the sarcomere’s center.
ATP breaks the cross-bridge, detaching myosin.
Myosin re-cocks, ready to bind again.
Explain the role of calcium ions in muscle contraction
Calcium binds to troponin, causing tropomyosin to move and expose actin-binding sites for myosin heads.
Describe the structure of a synovial joint
Bones covered with cartilage for cushioning.
Synovial capsule filled with synovial fluid for lubrication.
Ligaments stabilize and allow controlled movement.
Give two examples of synovial joints and their movements
Ball-and-socket joint (hip): Allows rotation, flexion, and extension.
Hinge joint (knee): Permits flexion and extension only.
Explain the role of synovial fluid in joints
Reduces friction, lubricates joint surfaces, and nourishes cartilage.
What are the main minerals stored in bones, and why are they important?
Calcium: Vital for muscle contraction, nerve conduction, and blood clotting.
Phosphate: Essential for DNA structure and energy metabolism.
Describe the process of blood cell production in bones
Red bone marrow produces red blood cells, white blood cells, and platelets from multipotent stem cells.
explain how bones contribute to movement
Bones act as levers for muscles to pull on, enabling movement at joints.
Explain the role of agonist and antagonist muscles in movement
The agonist contracts to create movement, while the antagonist relaxes to control and stabilize it.
give an example of an antagonist muscle pair
Biceps (agonist) and triceps (antagonist) during arm flexion.
A patient has a torn ligament. Explain why this affects joint stability
Ligaments connect bones and provide joint stability. A torn ligament reduces joint support, increasing the risk of dislocation.
Describe what happens at the neuromuscular junction when a muscle contracts
Nerve impulse triggers acetylcholine release.
Acetylcholine binds to receptors, opening channels for sodium ions.
Sodium influx generates an action potential in the muscle fibre, leading to contraction.
A patient is unable to produce ATP effectively. Explain how this impacts muscle function
ATP is needed to break cross-bridges and re-cock myosin heads. Without ATP, muscles remain contracted, causing stiffness (e.g., rigor mortis).
compare the movement allowed by fibrous cartilaginous, and synovial joints
Fibrous: Immovable (e.g., skull).
Cartilaginous: Slightly movable (e.g., ribs).
Synovial: Freely movable (e.g., hip).
Explain why cardiac muscle is unique
It is striated like skeletal muscle but involuntary like smooth muscle, and its intercalated discs allow synchronized contractions.
What happens to the sarcomere during muscle contraction
The sarcomere shortens as actin and myosin filaments slide past each other, but the filaments themselves do not change length.
describe two functions of the musculoskeletal system besides movement.
Blood cell production in red bone marrow.
Mineral storage (e.g., calcium and phosphate).
