Heart

Question 1

Auricles (auricular appendages)

Answer 1

outpouchings from the walls of the right and left atria

Question 2

Borders of the heart

Answer 2

• right border = right atrium
• Left border = left atrium
• Inferior border = right ventricle and part of left ventricle

Question 3

Surfaces of the heart

Answer 3

• base/ posterior surface = left atrium, part of right atrium
• Inferior / diaphragmatic surface = left ventricle, part of the right ventricle
• Anterior / sternocostal surface = right ventricle
• Left pulmonary surface = left ventricle
• Right pulmonary surface = right atrium

Question 4

Coronary circulation

Answer 4

major muscular arteries lie in sulci (grooves on external surface of heart)
• Left and right coronary arteries arise from ascending aorta and then branch further to supply specific heart regions
• Cardiac veins return venous blood to coronary sinus which enters right atrium

Question 5

Right coronary artery

Answer 5

supply parts of the conducting system of the heart, the right atrium, right ventricle, part of the left ventricle, and part of the interventricular septum.
• Branches to the sinoatrial node and atrioventricular node supply these major components of the electrical conducting system of the heart.
• The right marginal artery supplies the inferior border of the heart.
• The posterior interventricular artery (PIV) is the continuation of the right coronary artery on the inferior (diaphragmatic) surface of the heart - runs in the posterior interventricular sulcus and supplies both ventricles.

Question 6

posterior interventricular artery (PIV)

Answer 6

continuation of the right coronary artery on the inferior (diaphragmatic) surface of the heart - runs in the posterior interventricular sulcus and supplies both ventricles.

Question 7

Left coronary artery

Answer 7

supply parts of the conducting system of the heart, the left atrium, most of the left ventricle, part of the right ventricle, and part of the interventricular septum.
• only runs a short course before it divides into 2 large terminal branches:
1. Anterior interventricular artery (or the left anterior descending; ‘LAD’)
2. Circumflex artery (abbreviated to ‘Cx’).
• The anterior interventricular artery (LAD) runs in the anterior interventricular sulcus towards the apex- supplies both ventricles.
• One or two diagonal branches arise from the LAD.
• circumflex artery runs around the heart onto the inferior / diaphragmatic surface- supplies the left atrium, part of the right ventricle and the left ventricle.
• left marginal artery arises from the circumflex and supplies the left ventricle.

Question 8

2 terminal branches of left coronary artery

Answer 8

1. Anterior interventricular artery (or the left anterior descending; ‘LAD’)
2. Circumflex artery (abbreviated to ‘Cx’).

Question 9

Anterior interventricular artery (or the left anterior descending; ‘LAD’)

Answer 9

runs in the anterior interventricular sulcus towards the apex- supplies both ventricles.
• One or two diagonal branches arise from the LAD.
- septal branches arise from LAD as well

Question 10

Circumflex artery (abbreviated to ‘Cx’).

Answer 10

runs around the heart onto the inferior / diaphragmatic surface- supplies the left atrium, part of the right ventricle and the left ventricle.
• obtuse marginal artery arises from the circumflex and supplies the left ventricle.

Question 11

Right marginal artery

Answer 11

supplies the inferior border of the heart.

Question 12

posterior interventricular artery (PIV)

Answer 12

continuation of the right coronary artery on the inferior (diaphragmatic) surface of the heart - runs in the posterior interventricular sulcus and supplies both ventricles.

Question 13

Right dominant circulation

Answer 13

the PIV arises from the right coronary- both the right and left coronary arteries supply the left ventricle.

occlusion of the left main stem would impair blood flow to part of, but not the entire left ventricle.

Question 14

Left dominant circulation

Answer 14

the PIV arises from the circumflex artery; the left coronary artery supplies the entire left ventricle.

blockage of the left main stem occludes blood flow to the entire left ventricle.

Question 15

Right atrium

Answer 15

receives deoxygenated blood from the body via the superior and inferior venae cavae, and from the heart via the coronary sinus

Question 16

Main features of right atrium

Answer 16

Interatrial septum
Fossa ovalis
Crista terminalis
Tricupsid valve

Question 17

Interatrial septum

Answer 17

separates right atrium from the left atrium

Question 18

Fossa ovalis

Answer 18

a depression in the interatrial septum, remnant of the foetal foramen ovale. In the foetus the foramen ovale shunts oxygenated blood from the right atrium to the left atrium- bypassing the lungs.

Question 19

Crista terminalis

Answer 19

muscular ridge that separates the smooth-walled posterior part of the atrium from the anterior part, which has a ridged, muscular wall. The ridges are pectinate muscles and extend into the right auricle. The parts of the right atrium on either side of the crista have different embryological origins.

Question 20

Right ventricle

Answer 20

pumps the deoxygenated blood that it receives from the right atrium into the pulmonary trunk, which bifurcates into a left and right pulmonary artery.
• The pulmonary valve at the entrance of the pulmonary trunk prevents backflow of blood into the right ventricle.
• As contraction of the right ventricle propels blood into the pulmonary trunk, the wall of the right ventricle is thicker than that of the right atrium.

Question 21

Right ventricle contains:

Answer 21

interventricular septum
trabeculae carneae
papillary muscles
chordae tendineae
moderator band

Question 22

interventricular septum

Answer 22

Separates left and right ventricle

Question 23

papillary muscles

Answer 23

modified regions of trabeculae carneae, which project into the lumen of the ventricle

Question 24

trabeculae carneae

Answer 24

muscular ridges on the internal wall

Question 25

chordae tendineae

Answer 25

fibrous cords which connect the tips of the papillary muscles to the valve

Question 26

moderator band

Answer 26

modified region of the trabeculae carneae which connects the interventricular septum to one of the papillary muscles.

Question 27

Left atrium

Answer 27

receives oxygenated blood from the lungs via the pulmonary veins (2 from each lung). • it has a thinner wall compared to the ventricles and internally has a smooth-walled posterior part and an anterior part bearing pectinate muscles. • From the left atrium, blood flows into the left ventricle via the left atrioventricular valve (mitral valve)- flow of blood is mostly passive, but the left atrium does contract to empty fully.

Question 28

Left ventricle

Answer 28

pumps the oxygenated blood that it receives from the left atrium into the aorta. • The first branches from the aorta are the coronary arteries. • The aortic valve at the entrance to the aorta prevents backflow of blood into the left ventricle. • Because contraction of the left ventricle propels blood into the systemic circulation, the wall of the left ventricle is thicker than that of the right ventricle.

Question 29

Left ventricle contains:

Answer 29

• trabeculae carneae • papillary muscles; two in the left ventricle • chordae tendineae that connect the tips of the papillary muscles to the mitral valve.

Question 30

Atrioventricular valve

Answer 30

When the ventricles contract (ventricular systole), pressure rises inside the ventricles. This rise in pressure has the potential to force blood back into the atria. • The tricuspid and mitral valves close during ventricular contraction and prevent regurgitation of blood back into the atria, ensuring that blood can only flow out the ventricles via the great vessels (the pulmonary trunk and aorta). • The papillary muscles and chordae tendineae allow the closed valves to resist the pressure generated inside the ventricles during contraction and prevent them from being forced open. As pressure rises in the ventricles, the valve cusps, which project into the ventricle, start to close passively. When the ventricles contract, the papillary muscles also contract. The papillary muscles tense the cords, which in turn ‘pull’ on the valve cusps and prevent them everting into the atria.

Question 31

Semilunar valves

Answer 31

aortic and pulmonary valves are called semilunar valves, as their cusps are semi-circular (half-moon) shaped. • They prevent the backflow of blood from the aorta and pulmonary trunk into the left and right ventricles, respectively, that would otherwise occur at the end of ventricular contraction. • Each semilunar valve has 3 semi-circular cusps. • Each cusp is attached to the inner wall of the vessel, with a free edge that projects into the vessel lumen forming a pocket, or sinus, between its free edge and the vessel wall. When blood is forcefully propelled from the ventricles during ventricular systole, the valve cusps are ‘flattened’ onto the vessel wall and blood flows through the valve unimpeded. At the end of ventricular systole, pressure in the ventricles drops. Once pressure in the ventricle is less than that in the vessel (aorta or pulmonary trunk), blood in the vessel starts to flow back towards the heart. As it flows back, blood is immediately ‘caught’ in the valve cusps. The sinuses rapidly fill with blood and the cusps balloon out into the lumen. The free edges of the three valve cusps contact each other in the lumen and close the valve orifice. • In the aorta, the right and left coronary arteries arise from two of the three aortic sinuses, hence the coronary arteries fill during ventricular relaxation (diastole).

Question 32

How many cusps does each semilunar valve have

Answer 32

3 Each cusp is attached to the inner wall of the vessel, with a free edge that projects into the vessel lumen forming a pocket, or sinus, between its free edge and the vessel wall. When blood is forcefully propelled from the ventricles during ventricular systole, the valve cusps are ‘flattened’ onto the vessel wall and blood flows through the valve unimpeded. At the end of ventricular systole, pressure in the ventricles drops. Once pressure in the ventricle is less than that in the vessel (aorta or pulmonary trunk), blood in the vessel starts to flow back towards the heart. As it flows back, blood is immediately ‘caught’ in the valve cusps. The sinuses rapidly fill with blood and the cusps balloon out into the lumen. The free edges of the three valve cusps contact each other in the lumen and close the valve orifice.

Question 33

Heart sound positions

Answer 33

• Aortic = 2nd intercostal space, just to the right of the sternum. • Pulmonary = 2nd intercostal space, just to the left of the sternum. • Tricuspid = 5th intercostal space, just to the left of the sternum. • Mitral = 5th intercostal space, left midclavicular line. listen to the heart sounds in the regions where sound is transmitted, rather than directly over the valve

Question 34

Conducting system of the heart

Answer 34

• Specialised cells in the heart generate and conduct the electrical impulses that stimulate myocardial contraction. • Cells in the sinoatrial (SA) node spontaneously generate electrical impulses; it is the ‘pacemaker’ of the heart. It is located at the superior end of the crista terminalis. • Impulses from the SA node stimulate contraction of the atria. • Impulses are conducted to the atrioventricular (AV) node, located at the inferior end of the interatrial septum. • From the AV node, conducting fibres form the atrioventricular bundle (Bundle of His). • The atrioventricular bundle divides into two groups of fibres - the right and left bundle branches. • The left and right bundle branches give rise to Purkinje fibres that enter the myocardium of the left and right ventricles, respectively, and stimulate contraction.

Question 35

Rate of impulses from SAN

Answer 35

• The SA node generates impulses at a rate of approximately 70 per minute.

Question 36

Percentage of SAN supplied by left or right coronary artery

Answer 36

The SA node is supplied by the RCA in approximately 60% of people and by the LCA in approximately 40% of people.

Question 37

Blood supply to the conducting system

Answer 37

The SA node is supplied by the RCA in approximately 60% of people and by the LCA in approximately 40% of people. • The AV node is usually supplied by the posterior interventricular artery. In most people, the PIV arises from the RCA. • In most people, the LCA supplies the Bundle of His • Occlusion of either coronary artery can therefore result in conduction abnormalities, in addition to myocardial ischaemia.

Question 38

Innervation of the heart

Answer 38

innervated by sympathetic and parasympathetic fibres- act upon the SA node and can change the rate and force of myocardial contraction. • Sympathetic stimulation increases the heart rate and force of contraction. • Parasympathetic stimulation slows the heart rate and force of contraction. • also innervated by visceral afferent fibres- convey sensory information from the heart back to the CNS.

Question 39

Referred pain

Answer 39

if the myocardium is ischaemic, this visceral sensory information is relayed back to our conscious perception and may be perceived as pain, burning, tightness or pressure in the chest. Typically, the pain cannot be pinpointed, but is felt generally in the chest, the left side of the neck and / or the left arm.

Question 40

3 main sulci of the heart

Answer 40

Coronary sulcus (atrioventricular groove) Anterior interventricular sulcus Posterior interventricular sulcus

Question 41

Posterior interventricular sulcus

Answer 41

located on the posterior surface of the heart and represents the separation of the left and right ventricle. It contains the posterior interventricular artery and the middle cardiac vein.

Question 42

Coronary sulcus (atrioventricular groove)

Answer 42

circles around the heart and represents the separation of the atria from the ventricles. It contains the right coronary artery, circumflex branch of the left coronary artery, small cardiac vein and coronary sinus

Question 43

Anterior interventricular sulcus

Answer 43

located on the anterior surface of the heart and represents the separation of the left and right ventricle. It contains the anterior interventricular artery (also known as the left anterior descending artery) and great cardiac vein.

Question 44

Which structure forms the base of the heart

Answer 44

Left atrium

Question 45

Pericardial sinuses

Answer 45

passageways formed the unique way in which the pericardium folds around the great vessels. • oblique pericardial sinus is a blind ending passageway located on the posterior surface of the heart. • transverse pericardial sinus is found superiorly on the heart. It can be used in coronary artery bypass grafting

Question 46

How many papillary muscles are there

Answer 46

five papillary muscles in total. Three are located in the right ventricle, and support the tricuspid valve. The remaining two are located within the left ventricle, and act on the mitral valve.

Question 47

What does the left circumflex artery supply

Answer 47

Left atrium and left ventricle - obtuse marginal artery branches off Cx

Question 48

What does the left anterior descending artery supply

Answer 48

Right ventricle, left ventricle and interventricular septum

Question 49

What does the obtuse marginal artery supply

Answer 49

Left ventricle

Question 50

What does the right coronary artery supply

Answer 50

Right atrium and right ventricle SA and AV nodes Posterior part of interventricular septum

Question 51

What does the right marginal artery supply

Answer 51

Right ventricle and apex

Question 52

What do the small and middle cardiac veins drain

Answer 52

Right atrium, right ventricle, apex, SA and AV nodes

Question 53

What does the great cardiac vein drain

Answer 53

Left atrium, left ventricle, right ventricle, interventricular septum, AV bundles

Question 54

What does the left marginal vein drain

Answer 54

Left ventricle

Question 55

What does the left posterior ventricular vein drain

Answer 55

Right ventricle, Left ventricle

Question 56

Obtuse marginal artery

Answer 56

Arises from the circumflex and supplies the left ventricle

Question 57

Diagonal branches

Answer 57

Arise from LAD

Question 58

Coronary sinus

Answer 58

All cardiac veins drain into coronary sinus which enters right atrium

Question 59

Occlusion

Answer 59

Full blockage of blood vessel

Question 60

Stenosis

Answer 60

Partial blockage of blood vessel

Question 61

Pericardium

Answer 61

2 main layers: a tough external layer known as the fibrous pericardium, and a thin, internal layer known as the serous pericardium Found between the outer and inner serous layers is the pericardial cavity, which contains a small amount of lubricating serous fluid. The serous fluid serves to minimize the friction generated by the heart as it contracts.

Question 62

Fibrous pericardium

Answer 62

Continuous with the central tendon of the diaphragm, the fibrous pericardium is made of tough connective tissue and is relatively non-distensible. Its rigid structure prevents rapid overfilling of the heart, but can contribute to serious clinical consequences

Question 63

Serous pericardium

Answer 63

Enclosed within the fibrous pericardium, the serous pericardium is itself divided into two layers: the outer parietal layer that lines the internal surface of the fibrous pericardium and the internal visceral layer that forms the outer layer of the heart (also known as the epicardium). Each layer is made up of a single sheet of epithelial cells, known as mesothelium.

Question 64

Functions of pericardium

Answer 64

• Fixes the heart in the mediastinum and limits its motion. Fixation of the heart is possible because the pericardium is attached to the diaphragm, the sternum, and the tunica adventitia (outer layer) of the great vessels • Prevents overfilling of the heart. The relatively inextensible fibrous layer of the pericardium prevents the heart from increasing in size too rapidly, placing a physical limit on the potential size of the organ • Lubrication. A thin film of fluid between the two layers of the serous pericardium reduces the friction generated by the heart as it moves within the thoracic cavity • Protection from infection. The fibrous pericardium serves as a physical barrier between the muscular body of the heart and adjacent organs prone to infection, such as the lungs.

Question 65

Pericardial sinuses

Answer 65

passageways formed the unique way in which the pericardium folds around the great vessels. • oblique pericardial sinus is a blind ending passageway located on the posterior surface of the heart. • transverse pericardial sinus is found superiorly on the heart. It can be used in coronary artery bypass grafting

Question 66

Aorto-mitral continuity

Answer 66

fibrous sheet located between the noncoronary and left coronary leaflets of the aortic valve and anterior leaflet of the mitral valve

Question 67

Blood flow to the myocardium occurs mostly during…

Answer 67

Diastole

Question 68

What is responsible for the apex beat

Answer 68

Left ventricle

Question 69

Which valve Prevents high pressures developing in the jugular veins during ventricular systole.

Answer 69

Tricupsid valve

Question 70

Bicuspid aortic valve

Answer 70

1% of population • present earlier with murmurs due to aortic stenosis more likely

Question 71

Nodules of Arantius

Answer 71

- found in centre of free edges in aortic valve cusps to prevent friction when come together

Question 72

Lipofuscin

Answer 72

Yellow/brown pigment that accumulates in cardiac myocytes with increasing age

Question 73

Weibel-Palade bodies

Answer 73

are small storage granules located in endothelial cells comprising the intima of the heart and blood vessels. They are found in arteries, capillaries, veins, and the endocardium, but notably not in the lymphatic vessels. Contain Von Willebrand factors and other clotting factors

Question 74

Which vessel is the second to branch from the arch of the aorta?

Answer 74

Left common carotid artery

Question 75

In fetal life, which structure shunts blood from the aorta to the pulmonary trunk?

Answer 75

The ductus arteriosus shunts blood from the aorta to the pulmonary trunk. The ligamentum arteriosum is the fibrous, non-patient remnant of the ductus arteriosus. The ductus venosus shunts blood from the umbilical vein to the IVC. The ligamentum venosum is the fibrous, non-patent remnant of the ductus venosus.

Question 76

The right recurrent laryngeal nerve loops under which structure, before ascending back into the neck?

Answer 76

Right subclavian artery

Question 77

The inferior border of the heart is formed mostly by which structure?

Answer 77

Right ventricle

Question 78

Where is the crista terminalis located?

Answer 78

right atrium. It is a raised ridge that separates the smooth-walled part of the right atrium from the rough-walled part. The ‘rough’-walled part is characterised by muscular ridges called pectinate muscles. The smooth-walled and rough-walled parts of the right atrium have different embryological origins.

Question 79

Over which region of the chest wall would you place a stethoscope to best hear the tricuspid valve?

Answer 79

5th intercostal space, left sternal margin

Question 80

Over which region of the chest wall would you place a stethoscope to best hear the pulmonary valve?

Answer 80

2nd IC space at the left sternal margin.

Question 81

Over which region of the chest wall would you place a stethoscope to best hear the aortic valve?

Answer 81

2nd IC space at the right sternal margin.

Question 82

Over which region of the chest wall would you place a stethoscope to best hear the mitral valve?

Answer 82

5th IC space in the left midclavicular line.

Question 83

In more than 50% of individuals, the sinoatrial node (SAN) is supplied by which blood vessel?

Answer 83

Right coronary

Question 84

Which vessel is the AVN supplied by

Answer 84

Posterior interventricular artery (posterior descending artery)

Question 85

What is the axillary artery a continuation of

Answer 85

Subclavian artery in the axilla

Question 86

What is the brachial artery a continuation of

Answer 86

Axillary artery in the arm

Question 87

What does the left recurrent laryngeal nerve loop under

Answer 87

descends into the thorax and loops under the arch of the aorta before ascending back up to the larynx.

Question 88

What level is the arch of the aorta

Answer 88

T4

Question 89

At what level does the inferior vena cava enter the right atrium

Answer 89

T8

Question 90

Pectinate muscles

Answer 90

the ridges on the anterior wall of the right atrium.

Question 91

Crista terminalis

Answer 91

a muscular ridge that separates the smooth-walled posterior part of the atrium from the anterior part, which has a ridged, muscular wall.

Question 92

Fossa ovalis

Answer 92

a depression in the interatrial septum. It is the remnant of the foetal foramen ovale.

Question 93

Trabeculae carneae

Answer 93

muscular ridges on the internal wall of right ventricle

Question 94

Role of papillary muscles and chordae tendineae

Answer 94

functionally prevent regurgitation of ventricular blood via tensile strength by preventing prolapse or inversion of the valves during systole

Question 95

Which pulmonary artery is connected to the aortic arch via the Ligamentum arteriosum

Answer 95

Left

Question 96

At what level does the pulmonary trunk divide into 2 pulmonary arteries

Answer 96

T5-6

Question 97

Which 2 veins form the left brachiocephalic vein

Answer 97

Left internal jugular vein Left subclavian vein

Question 98

Where does the thoracic duct drain into

Answer 98

They point where the left brachiocephalic vein is formed

Question 99

Which nerve supplies the pericardium

Answer 99

Phrenic

Question 100

What are the names of the 2 structures within the foetal heart and great vessels that divert blood from the right side to the left side?

Answer 100

Ductus arteriosus Foramen ovale