B2: Circulatory System

1. Function

   Nota:

   • Carries Co2, hormones, glucose etc. 
2. Structure

   Nota:

   • Straw coloured liquid Contains dissolved substances and suspended cells.

1. Function

   Nota:

   • Carry oxygen to cells.
2. Structure

   Nota:

   • Biconcave disc shape - large surface area for absorbing O2 by diffusion.  No nucleus - makes more room for oxygen.  - cells die after 30 days Contain haemoglobin proten (iron) - allows O2 to bing to it, creating oxyhaemoglobin Flexible - can fit through small blood vessels

1. Function

   Nota:

   • Fight infection/defend against microbes
2. Structure

   Nota:

   • Lobed nucleus 2 mechanisms: - some engulf microbes - some produce antibodies to stick to microbes.

1. Function

   Nota:

   • Form clots which become scabs. - stops excess bleeding - prevents microbe infections
2. Structure

   Nota:

   • No nucleus Cell fragments Form mesh with blood platelets at site of cut.

1. Right Atrium
   1. Valve
      1. Right Ventricle
         1. Pulmonary Artery
            1. Lungs
               1. Pulmonary Vein
                  1. Left Ventricle
                     1. Valve
                        1. Left Atrium
                           1. Aorta

Nota:

• Carry blood away from heart High pressure Thick wall

Nota:

• Carry blood to heart Low pressure Valve to prevent backflow

Nota:

• Site of exchange between cells and blood. Thin walls for diffusion - lots of surface area Tiny holes for tissue fluid to leak