Applied anatomy and physiology

• Musculoskeletal system


  The skeletal and muscular system working together to allow movement which occurs at the joints
• Joint


  Where two or more bones meet to produce movement
• Types of freely movable joints that allow different movements

  • elbow, knee and ankle - hinge joint

  • hip and shoulder - ball and socket
• Structure of a synovial joint

  • synovial membrane

  • synovial fluid

  • joint capsule

  • bursae

  • cartilage

  • ligaments.
• Synovial Membrane


  Make the synovial fluid which prevents friction
• Synovial Fluid


  Lubricates the joints to prevent the bones from wearing away by friction
• Joint Capsule


  Limits movement to prevent injury
• Bursae


  Prevents friction between the bone and a muscle or a tendon and a bone
• Cartilage


  Prevents friction between the bones and acts as a shock absorber
• Isotonic contraction


  If muscle changes length during contraction
• Articulating Bones


  Where two or more bones meet to allow movement at a joint
• Tendons


  Fibrous tissues that join bone to muscle
• Ligaments


  Strong, flexible fibre that connects bones to other bones
• Flexion


  Movement decreasing the angle between body parts (bending)
• Extension


  Movement increasing the angle between body parts (straightening)
• Dorsi-Flexion


  Flexing the toes so that they move closer to the shin
• Plantar-Flexion


  Extending the toes down, away from the shin
• Adduction


  Movement of a body part toward the body's midline
• Abduction


  Movement of a body part away from the body's midline
• Circumduction


  A circular movement of the limb
• Rotation


  The action of rotating around an axis or centre
• Voluntary Muscle


  A muscle which is controlled by an individual
• Involuntary Muscle


  A muscle which is not under an individual's control
• Cardiac Muscle


  An involuntary muscle found in the wall of the heart
• Antagonistic Pair


  Two muscles working together. One contracts while the other relaxes.
• Agonist


  Muscle or group responsible for the movement.
• Antagonist


  Acts to produce the opposite action of the agonist.
• Isometric Contraction


  Where a muscle contracts but the length of the muscle does not change (therefore it doesn't move)
• Eccentric Contraction


  Occurs when the muscle lengthens due to a greater opposing force.
• Concentric Contraction


  Occurs when the muscle shortens, therefore generating force.
• Is expiration (exhaling at rest) an active or passive process

  Passive
• Is inspiration (inhaling at rest) an active or passive process

  Active
• Pathway of air


  Mouth/nose

  Trachea

  Bronchi

  Bronchioles

  Alveoli
• Alveoli


  Small air sacs in the lungs where gaseous exchange occurs
• Gaseous exchange


  Where oxygen from the air in the alveoli moves into the blood in the capillaries, while carbon dioxide moves from the capillaries into the air in the alveoli
• Features that assist in gaseous exchange


  • large surface area of alveoli

  • moist thin walls (one cell thick)

  • short distance for diffusion (short diffusion pathway)

  • lots of capillaries

  • large blood supply

  • movement of gas from high concentration to low concentration
• Capillary structure and function


  Function - to exchange materials between blood and cells. Blood flow is slow (allows more time for exchange of materials).

  No outer layer, muscle layer or elastic layer - shortens diffusion distance, not necessary (low blood pressure).

  Endothelial layer - one cell thick (short distance)

  Numerous and branched - large surface area.

  Narrow diameter - can permeate tissues, short diffusion distance.

  Narrow lumen - forces red blood cells to squeeze flat against side of the capillary (shorter distance).

  Space between endothelial cells - white blood cells can exit.
• Artery structure and function


  Function - transport blood away from the heart rapidly and under high pressure.

  Thick muscle layer - smaller arteries can constrict/dilate to control volume.

  Thick elastic layer - elastic walls stretch at systole and recoils at diastole. (Maintains high blood pressure and smoothes surges of heart beating.

  Thick wall - prevents bursting.

  No valves - Not needed, high pressures prevents backflow.
• Vein structure and function

  Function - return blood to the heart, slowly w/ low pressure.

  Thin muscle layer - not necessary to control flow back to heart.

  Thin elastic layer - pressure too low to create recoil.

  Thin wall overall - pressure too low for risk of bursting. (allow veins to be compressed by body muscles).

  Valves throughout - prevent backflow of blood.

  Wide lumen
• Diffusion pathway


  The distance travelled during diffusion. The diffusion pathway is short in gaseous exchange.