Anatomy of the Heart and Coronary Circulation Flashcards
What is the mediastinum
The space between the pleural cavities , occupying the centre of the thoracic cavity
What is the pericardium
Fluid filled sac that surrounds the heart and the roots of the great vessels
What are the 2 parts of the pericardium
Fibrous pericardium
Serous pericardium
What is the fibrous pericardium
Tough connective tissue outer layer
What are the 2 layers of the serous pericardium
Parietal and visceral
Where are the parietal and visceral layers of the serous pericardium
Parietal - Lines the inner surface of the fibrous pericardium
Visceral - adheres to the heart and forms the outer covering
Where does the pericardial cavity lie and what does it contain
between the visceral pericardium and parietal pericardium filled with the pericardial fluid
What are the roles of the pericardial fluid
- Acts as a shock absorber by reducing friction between the pericardial membranes
- Keeps the heart contained in the chest cavity
- Prevents the heart from over expanding when blood volume increases
- Limits heart motion
What do the partitions that divide the heart into four chambers generate on the surface of the heart
Grooves/Sulci
What are the sulci found on the heart
Coronary sulcus
Anterior and posterior Interventricular sulci
Describe the coronary sulcus
Circles the heart, separating the atria from the ventricles
Describe the inter ventricular sulci
Separates the two ventricles
What valves are found between the right atrium and right ventricle
The atrioventricular (tricuspid) valve
Where does the right atrium receive blood from
Superior and inferior vena cava (from the body) and the coronary sinus (from walls of the heart itself)
What is the triscupid valve attached to
The papillary muscles of the ventricular wall by the chordae tendinae (heart strings)
What is the role of chordae tendinae
Helps to stabilise the valve and prevent back flow
What valve is found between the left atrium and ventricle
The mitral (bicuspid) valve
What does the right atrium receive blood from
4 pulmonary veins
What is the valve between the left ventricle and aorta
Aortic valve
Where are semi lunar valves found
Between the ventricles and arteries
Are aortic valves usually tricuspid or bicuspid
Tricuspid
What can occur if the aortic valve is bicuspid
Usually no symptoms but middle age may result in it becoming stiff and thick causing aortic stenosis
How is the “lub” (S1) sound caused
The turbulence caused by the closure of the mitral and tricuspid valves at the start of systole
How is the “dub” (S2) sound caused
Closure of the aortic and pulmonary valves marking the end of systole
What time periods makes up systole and diastole
Systole = Period between S1 and S2 Diastole = Period between D2 and S1
What is an incompetent valve
Allows blood back into the chamber from which it was expelled
What is a stenotic valve
impedes blood flow from one chamber to the next
What is a calcified aortic valve
Valve is narrow and densely calcified, can inly put fingertip through
What is the cardiac skeleton made of
Four rings of CT with interconnecting areas in a place between the atria and the ventricles
What are the roles and functions of the cardiac skeleton
Helps maintain integrity of the openings it surrounds and provides points of attachment for the cusps
Dense CT partition that electrically isolates the atria from the ventricles.
What is the only connection between the antra and ventricles
the atrioventricular bundle that passes through the anulus
How does coronary blood flow relate to oxygen demand
When oxygen consumption and cardiac activity increases, coronary blood flow increases proportionate to the increase in oxygen consumption
Name 2 important regulators of coronary blood flow
Adenosine
Nitric oxide
When in the cardiac cycle does most coronary flow occur
during diastole
therefore tachycardia decreases time for coronary flow
How does coronary blood flow relate to arterial pressures
Over a range (50-120mmHg) coronary blood flow is relatively independent of arterial pressure
When arterial pressure increases the smooth muscle in the wall of the arterioles contracts to maintain a constant flow (auto regulation)
What is ischemic heart disease
A condition where the flow of blood to the heart muscles is restricted, normally caused by narrowed arteries due to plaque
What is the dental relevance of ischemic heart disease
May present with tooth or jaw aches.
Dental treatment may provoke symptoms or acute complications
