Topic 11: Cardiovascular System - Cardiac Physiology Flashcards
What are the 2 parts of the cardiovascular system?
- heart
- Conduction System
What is the heart? (2)
- dual pump with valves
- muscle cells connected by gap junctions
What type of cells is the conduction system made of?
- non-contractile cardiac muscle cells that are modified to initiate and distribute impulses throughout the heart
What does the conduction system produce?
- APs spontaneously (no stimulus) BUT at different rates
What are the 4 parts of the conduction system?
- sinoatrial node
- Atrioventricular node
- Bundle of His (AV bundle)
- Purkinje fibers
Where is the SA node located?
- right atrium
What is the rate of APs in the SA node? (2)
- 100 APs/min
- modifed by PSNS to be 75 AP/min at rest_
Why is the SA node called the pacemaker of the heart?
- produces APs faster than other areas
Where is the atrioventricular node located?
- right atrium
What is the rate of AP in the atrioventricular node?
- 50 APs/min
Where does the Bundle of His originate from?
- AV node
What is the Bundle of HIs for?
- only route for electrical activity to go from atria to ventricles and bundle branches (right and left)
What is the rate of APs in the bundle of His?
30 APs/min
in lecture, you can still have this rate but it would not be enough to survive
pathway of AP in the heart diagram
If the conduction system is damaged, which part then becomes the pacemaker? (3)
- the next fastest part
- ie. if SA node is damaged, AV node takes over
- but atria may not contract and ventricles contract at AV speed of 50 beats/min
