Layers of the heart Flashcards
How many layers of tissue form the heart wall?
3
What is the outer layer of the heart called?
Pericardium
What is the pericardium composed of?
Two sacs that surround the heart, the fibrous pericardium and the serous pericardium
How is the structure of fibrous pericardium adapted to support the heart?
Inelastic and fibrous in nature
Prevents the over distension of the heart
What is attached to the fibrous pericardium?
a double layer of serous pericardium
How many layers is the serous pericardium split into?
2 layers
What are the layers of the serous pericardium called?
The parietal layer (the outer layer)
followed by a space
Visceral layer (attached to the myocardium)
What is the myocardium?
The heart muscle
What can be found in the space between the layers of the serous pericardium, what is its purpose?
A fluid that prevents the parietal and visceral layers from friction as the heart beats
What is the myocardium composed of?
Special cardiac muscles
These are only found in the heart
Explain the varying thickness of the myocardium?
Thickest at the apex (the bottom of the heart)
Thins out as it goes towards the base of the heart
What are the atria and the ventricles separated by?
A ring of fibrous tissue, which does not conduct electricity
What happens when a wave of electricity is passed down from the atrial muscles?
It can only spread to the ventricles through the conductivity system that bridges the fibrous ring from the aorta to the ventricles
What is the endocardium?
The inner layer of the heart
Where can the endocardium be found?
Lines the chambers and the valves of the heart
