Role of the muscular system GCSE

Muscles and Movement

Aims: Know the role of the muscular system. Understand the particular movements that various muscles allow. Know the major movements specific muscles are responsible for.

Recap Quiz... What is the agonist muscle? What is the antagonist muscle? Identify one characteristic of CARDIAC muscle. What is the insertion of a muscle? Are skeletal muscles voluntary or involuntary?

Muscles and Movement Do muscles make up 20%, 40% or 60% of of total body mass? Muscles also allow us to move the body, stabilise joints, protects and keeps vital organs in place plus gives us our shape!

Muscle movement categories MovementDefinition Flexors the muscles that bend a limb at a joint by contracting Extensors the muscles that work with and against the flexors and that straighten a limb at a joint by contracting. Adductors the muscles that move a limb towards the body. Abductors The paired muscles for adductors, which move a limb away from the body.

Muscle contractions Type of contraction:Explanation: Isotonic contractions: These can be CONCENTRIC or ECCENTRIC. Concentric: muscle shortens(muscle bulges e.g. bicep) Eccentric: muscle gradually lengthens and returns to normal shape/length. Isometric contractions: No actual movement or limb or joint, because muscles work to keep joint stable.

Task... Place your left arm around your right forearm with right arm out straight. Clench right fist and you will feel the isometric contraction in forearm.

Major muscles & movement functions:

Biceps and triceps Mainly involved in any movement of the arms, especially at elbow, including any throw e.g. javelin, ball or smash in tennis, badminton or volleyball. Which is the flexor and which is the extensor?

Hamstrings and quadriceps Mainly involved in any movement of the legs, especially kicking, e.g. a football, as well as running movements. Which is the flexor and which is the extensor?

Abdominals Allow movement around stomach and waist. Important for keeping body straight and upright. Also for exercises such as sit- ups. What type of contraction do the abdominals do in a sit-up?

Pectorals Allow the arm to be raised at the shoulders, so involved in tennis drive, shot putt and swimming strokes. What type of contraction do the pectorals do in the downward part of the butterfly stroke?

Gastrocnemius Involved in initial movement of the legs, specifically running and take off for a jump. Can you perform an eccentric contraction with the gastrocnemius muscle? Try it!

Question time Create a 4 mark question and answer. Create a specific sport and movement that has to be analysed in relation to: Agonist/antagonist muscles, Types of muscle contraction, Flexors, extensors, adductors & abductors, Origin and insertion.