Anatomy of the Heart and Coronary Circulation

Question 1

What is the mediastinum

Answer 1

The space between the pleural cavities , occupying the centre of the thoracic cavity

Question 2

What is the pericardium

Answer 2

Fluid filled sac that surrounds the heart and the roots of the great vessels

Question 3

What are the 2 parts of the pericardium

Answer 3

Fibrous pericardium

Serous pericardium

Question 4

What is the fibrous pericardium

Answer 4

Tough connective tissue outer layer

Question 5

What are the 2 layers of the serous pericardium

Answer 5

Parietal and visceral

Question 6

Where are the parietal and visceral layers of the serous pericardium

Answer 6

Parietal - Lines the inner surface of the fibrous pericardium
Visceral - adheres to the heart and forms the outer covering

Question 7

Where does the pericardial cavity lie and what does it contain

Answer 7

between the visceral pericardium and parietal pericardium filled with the pericardial fluid

Question 8

What are the roles of the pericardial fluid

Answer 8

• 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

Question 9

What do the partitions that divide the heart into four chambers generate on the surface of the heart

Answer 9

Grooves/Sulci

Question 10

What are the sulci found on the heart

Answer 10

Coronary sulcus

Anterior and posterior Interventricular sulci

Question 11

Describe the coronary sulcus

Answer 11

Circles the heart, separating the atria from the ventricles

Question 12

Describe the inter ventricular sulci

Answer 12

Separates the two ventricles

Question 13

What valves are found between the right atrium and right ventricle

Answer 13

The atrioventricular (tricuspid) valve

Question 14

Where does the right atrium receive blood from

Answer 14

Superior and inferior vena cava (from the body) and the coronary sinus (from walls of the heart itself)

Question 15

What is the triscupid valve attached to

Answer 15

The papillary muscles of the ventricular wall by the chordae tendinae (heart strings)

Question 16

What is the role of chordae tendinae

Answer 16

Helps to stabilise the valve and prevent back flow

Question 17

What valve is found between the left atrium and ventricle

Answer 17

The mitral (bicuspid) valve

Question 18

What does the right atrium receive blood from

Answer 18

4 pulmonary veins

Question 19

What is the valve between the left ventricle and aorta

Answer 19

Aortic valve

Question 20

Where are semi lunar valves found

Answer 20

Between the ventricles and arteries

Question 21

Are aortic valves usually tricuspid or bicuspid

Answer 21

Tricuspid

Question 22

What can occur if the aortic valve is bicuspid

Answer 22

Usually no symptoms but middle age may result in it becoming stiff and thick causing aortic stenosis

Question 23

How is the “lub” (S1) sound caused

Answer 23

The turbulence caused by the closure of the mitral and tricuspid valves at the start of systole

Question 24

How is the “dub” (S2) sound caused

Answer 24

Closure of the aortic and pulmonary valves marking the end of systole

Question 25

What time periods makes up systole and diastole

Answer 25

``` Systole = Period between S1 and S2 Diastole = Period between D2 and S1 ```

Question 26

What is an incompetent valve

Answer 26

Allows blood back into the chamber from which it was expelled

Question 27

What is a stenotic valve

Answer 27

impedes blood flow from one chamber to the next

Question 28

What is a calcified aortic valve

Answer 28

Valve is narrow and densely calcified, can inly put fingertip through

Question 29

What is the cardiac skeleton made of

Answer 29

Four rings of CT with interconnecting areas in a place between the atria and the ventricles

Question 30

What are the roles and functions of the cardiac skeleton

Answer 30

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.

Question 31

What is the only connection between the antra and ventricles

Answer 31

the atrioventricular bundle that passes through the anulus

Question 32

How does coronary blood flow relate to oxygen demand

Answer 32

When oxygen consumption and cardiac activity increases, coronary blood flow increases proportionate to the increase in oxygen consumption

Question 33

Name 2 important regulators of coronary blood flow

Answer 33

Adenosine | Nitric oxide

Question 34

When in the cardiac cycle does most coronary flow occur

Answer 34

during diastole | therefore tachycardia decreases time for coronary flow

Question 35

How does coronary blood flow relate to arterial pressures

Answer 35

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)

Question 36

What is ischemic heart disease

Answer 36

A condition where the flow of blood to the heart muscles is restricted, normally caused by narrowed arteries due to plaque

Question 37

What is the dental relevance of ischemic heart disease

Answer 37

May present with tooth or jaw aches. | Dental treatment may provoke symptoms or acute complications