PLEASE HELP!!!

[White dove]

Hello,

Please can someone help, i have tried to search this everywhere but don't how to answer this question...


How does the heart initiates and coordinates the contraction of the artries and ventricles??????????

Also

What are the properties of the respiratory surface and why are they important????


Hope to hear from you.



Thanks

[Revenged]

electrical activity of heart

SA node -> atria contraction -> AV node -> ventricular contraction


respiratory surface...

large surface area, thin walls, short distance => increase diffusion

surfactant => stops alveoli collapsing

[Happydadtoo]

After AV node come Bundle of His (or Purkinje fibres - either will do. Note various spellings of the fibres!)
Resp surfaces Q's (and ANY Q relating to diffusion) ALWAYS needs you to mention Fick's Law.
Arteries simply respond to pressure - stretch and recoil of ELASTIC fibres (don't mention muscle fibres - that's arterioles only and nothing to do with this!)

HD2

[bluhm]

More about the heart conduction system here:
http://www.biologyguide.net/bya1/bya1-10-8.htm

electrical activity of heart

SA node -> atria contraction -> AV node -> ventricular contraction


respiratory surface...

large surface area, thin walls, short distance => increase diffusion

surfactant => stops alveoli collapsing