Chapter 1.1 The Cardiovascular System Flashcards
What valve is in between the left atrium and the left ventricle?
The bicuspid valve
What valve is in between the right atrium and right ventricle?
Tricuspid valve
What does myogenic mean?
The heart muscle can be described as being myogenic, this means that it has the capacity to generate its own impulses
What does the heart beat start with?
With an electrical signal in the sinoatrial node (SAN) - this electrical impulse then spreads through the heart in what is often described as a wave of excitation
What is the Sinoatrial node (SAN or SA node)?
A small mass of cardiac muscle found in the wall of the right atrium that generates the heart beat. Is is more commonly called the pace maker
What causes the walls of the atria to contract?
An electrical impulse from the SAN which spreads through the walls of the atria, causing them to contract and forcing blood pressure into the ventricles
What is the atrioventricular node (AVN or AV node)?
This node relays the impulse between the upper and lower sections of the heart
Where is the atrioventricular node (AVN)?
In the atrioventricular septum
What is systole?
When the heart contracts
Purkinje fibres
Muscle fibres that conduct impulses in the walls of the ventricles
Bundle of His
A collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles
Why does the AVN delay the transmission of the cardiac impulse?
it delays it for 0.1 seconds to enable the atria to fully contract before ventricular systole begins
Which chambers of the heart are larger and why?
The ventricles because they have to pump the blood further
What is cardiac output?
The amount of blood ejected by the heart per minute - formula: stroke volume x heart rate
What is stroke volume?
The amount of blood ejected by the heart per beat
