Paper 1 Topics

• The Structure of the Skeleton


  The skeleton provides a framework for movement. It is made up of bones and joints of different types, which provide something for muscles to hold on to.The skeletal system and the muscular system - known collectively as the musculoskeletal system - work together to allow movement, which occurs at the joints. Different types of joints allow for different types of movement.

  
• Bones

  There are 4 types of bones - Flat Bones - Often quite large and usually protect vital organs.Long Bones - Enable large movements.Short Bones - Enable fine movements.Irregular Bones - Shaped to protect.The human body contains articulating bones, which meet at a joint to enable movement.
• The Functions of the Skeleton

  Support,Protection,Movement,Shape and Structure,Blood Cell Production,Storage of Minerals.
• Synovial Joints


  Synovial joints, also known as free movable joints, are the most common joints in the human body. They are located at the shoulder, elbow, hip, knee and ankle. Thy have particular structural features that are shown in the following diagram of the knee.

  
• Types of Freely Movable Joints

  The different types of synovial joints allow different types of movements to occur. For example:Ball and socket joints can move away from the body, back towards the body, and can also rotate. This range of motion makes them the most movable joint in the body. The shoulder joint and the hip joint are ball and socket joints.Hinge joints can only move in one direction, towards and away from each other, like the hinge on a door. the elbow, knee and ankle joints are all hinge joints.
• Joint Action and Movements

  Different joints allow different types of movement. For example:The hinge joints at the knee and elbow can only move in one direction, enabling flexion and extension.The hinge joint at the ankle enables plantar flexion and dorsiflexion.The ball and socket joints at the hip and shoulder enable rotation, adduction, abduction, as well as flexion and extension.
• The Muscular System


  The majority of movement in then body occurs at the shoulder, hip,knee and ankle joints so it is important to be able to identify the major muscle groups that operate at these joints:Shoulder: Deltoid, trapezius, pectorals, latissimus dorsi, biceps, triceps, rotator cuff.Elbow: Biceps, Triceps.Hip: Gluteals, hip flexors.Knee: Quads, Hamstrings.Ankle: Gastrocnemius, tibialis anterior.
• Muscles and Movement

  Muscles can only pull, not push. They are therefore arranged in pairs on either sides of joints. One muscle contracts and pulls while the other relaxes, and vice versa. The muscle that contracts is called the prime mover or agonist. The muscle that relaxes is called the antagonist. Muscle work in agnostic pairs.
• Obvious Agnostic Pairs

  Biceps and Triceps, acting at the elbow to create flexion and extension.Hip flexors and Gluteals: Acting at the hip to create flexion and extension.Hamstring Group and Quads: Acting at the knee to create flexion and extension.Tibialis anterior and Gastrocnemius: Acting at the ankle to create dorsiflexion and plantar flexion.
• Isotonic Contractions


  Thes occur when the muscle changes length when it contracts, and they result in limb movement. Isotonic contractions can be concentric (where the muscle contracts and shortens) or eccentric (where the muscle contracts and lengthens usually in the downwards phase of a movement).

  
• What is a fulcrum?

  The part of a lever system that pivots
• What is resistance/load?

  The weight to be moved by a lever system
• What is effort?

  The force applied to move the load, in the body usually a muscle
• What is a first class lever?

  Found at the elbow joint, where the triceps causes extension of the lower arm
• What is a second class lever?

  Found at the ankle, where the gastrocnemius causes plantar flexion
• What is a third class lever?

  The majority of the body's joints act as third class levers. For example, the bicep acting at the elbow to cause flexion
• What is mechanical advantage?

  The benefit to a lever system of having either a short resistance arm, giving rapid movements over a large range of movement, or a long resistance arm, giving the advantage of being able to move a heavy weight
• How do you calculate mechanical advantage?

  Effort arm divided by the resistance arm
• What is an agonist?

  The prime mover, muscle that causes movement
• What is an antagonist?

  Muscle that relaxes to allow the agonist to contract
• What are tendons?

  Attach muscles to bone
• What is an isotonic contraction?


  Muscle action where the muscle changes length, causes movement
• What is an isometric contraction?

  Muscle action where the muscle stays the same length, used in balances
• What is a concentric contraction?

  Isotonic contraction where the muscle shortens
• What is an eccentric contraction?

  Muscle action where the muscle lengthens, used to control downward movements
• What is the deltoid?

  Muscle that causes flexion and abduction at the shoulder
• What is the latissimus dorsi?


  Muscle that causes extension adduction at the shoulder
• What is the biceps?

  Muscle that causes flexion at the elbow
• What is the triceps?

  Muscle that causes extension at the elbow
• What are the hamstrings?

  Group of muscles that cause flexion at the knee
• What are the quadriceps?

  Group of muscles that cause extension at the knee
• What are the hip flexors?

  Main agonists at the hip during hip flexion
• What are the gluteals?

  Main agonists at the hip during hip extension
• What is the tibialis anterior?

  Muscle that causes dorsiflexion at the ankle
• What is the gastrocnemius?

  Muscle that causes plantar flexion at the ankle
• What is the rotator cuff?

  Group of muscles causing rotation at the shoulder
• Flexion at shoulder =


  Humerus, scapula. main agonist is the deltoid, antagonist is the latissimus dorsi
• Extension at shoulder =

  Humerus, scapula. Main agonist is the latissimus dorsi, antagonist is the deltoid
• Adduction at shoulder =


  Humerus, scapula, latissimus dorsi and pectorals are agonists, concentric. deltoid is antagonist, eccentric.
• Abduction at shoulder =


  Humerus, scapula, deltoid is agonist, latissimus dorsi and pectorals are antagonists