Very thin blood vessels with very thin walls

1. Trachea+Alveoli

b. X=o2 y=co2

c. 8.4

d. Diffusion

heart = Lungs=loss of co2 and blood gets oxygenated

           =tricuspid valve = prevents backflow

           =Heart Beat=0.3,3,75

Pez=surface area, blood supply and thin walls

Ojo= a,b,g,f,d

Graph= temp abajo

Veins have a bigger lumen than arteries to help blood Flow despite the lower pressure. They also have valves to help keep the blood Flowing in the right  direction.

Lymphocytes produce antibodies and some convert into Memory cells

Pathogens cause disease

Phagocytes detect foreign things to the body and they are Non specific