Module 7 Cardiovascular A & P Flashcards
Where is the heart located?
In the mediastinum, behind the sternum
What covers the heart?
Pericardium
Pericardium has 2 main parts, what are they?
Fibrous pericardium
Serous Pericardium
Fibrous pericardium
Superficial (surface) portion of pericardium
Tough, loose-fitting inextensible sac; ANCHORD TO SURROUNDING WALLS
Serous pericardium, what is its 2 divisions?
Moist; smooth, double layered.
Parietal and Visceral layer
Parietal layer of Serous pericardium?
fused to fibrous pericardium
Visceral layer of Serous pericardium?
epicardium (most inner part of the serous pericardium); integral part of heart wall.
Pericardial space? what does it do?
10-15 mL pericardial fluid
It separates 2 layers; which provides protection from friction.
Covering of heart order, from outside to in?
Fibrous pericardium
Serous pericardium:
- Parietal
- Visceral
Myocardium
Endocardium (literal edge)
which vessels do the pericardial sac attach to?
Large vessels that enter and exit the heart.
3 layers of the wall heart
Epicardium
myocardium
Endocardium
Epicardium:
Outer layer of the heart wall (visceral layer of serous pericardium)
Myocardium
hint think cardiac muscles
Thick, contractile middle layer of heart wall; compresses the heart cavities.
Endocardium
Delicate inner layer of endothelial tissue:
continuous with all blood vessels.
Myocardium: if one intercalated ‘disk’ contracts why do all myocardial fibers contract?
Myocardial cells are continuous and wrap around the heart through out. —disks are interconnected
Frank-starling mechanism
Increase in sarcomere length = increased cross-bridge cycling (contraction)
Sarcomere?
basic contractile unit of muscle fiber responsible for muscle contraction
Pre-contraction length = what?
“preload” of sarcomere
What does the frank-starling mechanism tell us?
The more the muscle stretches, the more force is used during contraction
The heart has 2 superior chambers known Atria/atriums. what is there purpose?
Receiving chambers…for blood coming from veins.
When Atria contract, what do they push blood into?
Ventricles.
Why is myocardial walls in each atria not thick compared to ventricles?
Little pressure is needed to move blood a small distance for the Atria.
The Ventricular have more distance to pump so they are thicker.
ventricles are the 2 lower chambers, what is their role?
Pumping chambers.
Both atria and ventricles are sepearted by the septum, If the atria are separated by the interatrial septum, what are the ventricles separated by?
Interventricular septum