Rebecca Eddy (Wednesday December 8, 2009)

What we did:

• Marked the homework from Tuesday and then handed it in (blood flow from capillaries back to capillaries in reverse).
• Went through page 320.
• Learned about heart sounds.
• Learned about heart beats and took notes on them.
• SA and AV nodes. 
• Gave us the pig dissection sheet for Wednesday.

Key Definitions:

• Myogenic muscle: Muscle that contracts due to nerves within the tissue.
• Node: Cluster of nerves.
• SA and AV nodes: The SA node acts as a pacemaker and is located in the upper right atrium. The AV node acts as the conductor and they both send nerve impulses. The SA node activates the AV node.
• Purkinje fibres: Fibres coming from the AV node to the bottom of the ventricles and then branch upwards. 
• Systole: Pressure in circulatory system due to ventricle contraction.
• Diastole: Blood pressure in circulatory system due to relaxed ventricles.
• "Lubb": The sound that the closing of AV valves makes. It is louder than "dubb".
• "Dubb": The sound that the closing of semilunar valves makes.

Thoughts and Opinions:

I think that there was alot of definitions to take in. After studying a bit though, it was pretty easy to understand. I think the most difficult part to understand was the SA and AV nodes.  

Above and Beyond:

    
This is a picture of the heart that shows you where the AV and SA nodes are. It also shows you the way the nerve impulses go.