Musculoskeletal system

Question 1

Muscle

Answer 1

made up of bundles of muscle cells/muscle fibres held together by connective tissue

Question 2

What makes muscle fibres

Answer 2

contain myofibrils, multinucleated

Question 3

What do myofibrils contain

Answer 3

Actin and Myosin

Question 4

Muscle fibres

Answer 4

responsible for contraction of the muscle as a whole, structure gives banded pattern (Striated muscle)- from repeating sections of sarcomeres which appear under the microscope as alternating dark and light bands, Consists of lots of sarcomeres next to each other, connect together at the “z” line

Question 5

Actin

Answer 5

Thinner lighter line, surrounds myosin

Question 6

Myosin

Answer 6

Thicker and darker lines, between actin protein

Question 7

How does contraction of muscle fibres occur

Answer 7

Myosin filaments pull (using ATP) on the actin filaments- contraction occurs as the “z” lines are forced closer together

Question 8

Sliding filament theory

Answer 8

Actin and myosin slide over each other to contract, Stimulus received (nervous system signal)- myosin uses energy to pull on actin which causes the muscle to contract, Nervous system stimulus stops- myosin and actin detach and muscle relaxes, All contract together as if one shortens they all do as they are attached at the “z” line

Question 9

Skeletal muscles

Answer 9

Attached to bones by tendons, Pull bones together (can’t push as they can only contract), Paired to perform opposite actions- antagonistic pairs

Question 10

Agonist muscles

Answer 10

brings about desired movement (prime mover), contracted, bicep contracting and pulling on the bone

Question 11

Antagonist muscle

Answer 11

brings about movement opposite to the agonist, relaxed, triceps

Question 12

Example of an antagonistic pair

Answer 12

biceps and triceps, Biceps pull to reduce the elbow angle (flection), triceps on other side pull on bone to increase angle