Cardiovascular Physiology 7 Flashcards
What kind of tissue is the Cardiac Skeleton made of?
Dense connective tissue
What does the Cardiac Skeleton include?
The valve rings of the heart and the dense connective tissue between the heart valves
What does the Cardiac Skeleton do for the heart?
Provides structure and support for the heart and physically separates the atria from the ventricles
What does the Cardiac Skeleton being electrically inactive do for the heart?
Blocks the direct spread of electrical impulses from atria to the ventricles
What is a Syncytium?
A set of cells that act together
How does an action potential spread from heart cell to heart cell?
Through gap junctions
Why is the Heart called a functional Syncytium?
Because when one heart cell is excited the it spreads over both ventricles or both atrium
What are the two functional Syncytia of the heart?
The atrial syncytium and the ventricular syncytium
What do the two Syncita give the heart?
An all or none property where either all the cells in a syncytia respond or none respond
What is Automaticity (autorhythmicity)?
The ability of the cardiac muscle to contract in the absence of neural or hormonal stimulation, as a result of action potentials it generates itself
What is the Automaticity (autorhythmicity) of the heart in origin?
Muscular in origin
What are the two types of cardiac muscle cells or myocytes?
- Contractile cells
* Conducting cells
What do the Contractile cells of the heart do?
Perform the mechanical work of pumping or contracting to propel blood forward
What percent of cells in the heart are contractile cells?
99%
What are contractile cells stimulated by?
An action potential transferred to them by gap junctions
