Structure Of Heart

Question 1

Apex beat:

Answer 1

Left 5th intercostal space, mid-clavicular line

Question 2

Right heart border: SVC – right atrium

Answer 2

Left heart border: Aortic knuckle – left pulmonary artery – LA appendage – left ventricle

Question 3

Anteriorly: mainly right ventricle

Answer 3

Posteriorly: mainly left atrium and pulmonary veins

Question 4

Mediastinum- Area between right and left pleura, divided as follows:

Answer 4

Plane between sternal angle and T4/5 divides superior and inferior mediastinum

Pericardium divides anterior, middle and posterior mediastinum

Question 5

Pericardium consists of fibrous (parietal) and visceral layers

Answer 5

Push your fist into a soft balloon – explains two layers and pericardial reflections

Question 6

Pericardial space

Answer 6

Is a potential space

Question 7

Cardiac tamponade

Answer 7

Rapid collection of pericardial fluid is restricted and impairs filling

Question 8

Pleural reflection

Answer 8

allows drainage of pericardial fluid from the left of the xiphisternum

Question 9

Atrioventricular valves (mitral and tricuspid)

Answer 9

are an intrinsic part of their ventricle

Disorders of the ventricle often affect function of the relevant Atrioventricular valve

Question 10

Papillary muscles (part of ventricle)

Answer 10

attach to atrioventricular valves via chordae tendinae

Question 11

Semilunar valves (aortic and pulmonary)

Answer 11

are an intrinsic part of their great artery

Disorders of the aorta or pulmonary artery often affect function of their respective valves

Question 12

Arterial blood

Answer 12

is blood leaving the heart – not always fully oxygenated (PA)

Question 13

Venous blood

Answer 13

is blood returning to the heart – not always deoxygenated (PV)

Question 14

The pulmonary artery

Answer 14

carries deoxygenated blood from the heart

Question 15

The pulmonary veins

Answer 15

carry oxygenated blood back to the heart

Question 16

LV is thick walled and muscular (systemic ventricle)

Answer 16

RV has thin muscular wall

Atria are thin walled

Question 17

Four pulmonary veins (usually 4) drain into the left atrium

Answer 17

Coronary sinus drains blood from the heart muscle into the right atrium

Question 18

Right atrium has smooth (from sinus venosus) and trabeculated (from original atrium) portions

Answer 18

Crista terminalis separates smooth and trabeculated portions of right atrium

Question 19

Fossa ovalis

Answer 19

is the remains of the foramen ovale which was patent in foetal life

Question 20

Cardiac muscle cells cross link

Answer 20

They join at intercalated discs

Question 21

Coronary arteries arise from the aortic root sinuses and supply the heart itself

Answer 21

Coronary arteries are epicardial and therefore accessible to the surgeon (bypass surgery)

Two main coronary arteries, left and right

Question 22

Coronaries are functional end arteries

Answer 22

unless collateral supply has developed

Question 23

The left main stem divides into left anterior descending (LAD) and circumflex (Cx) branches

Answer 23

• The LAD runs in the anterior interventricular groove
• The LAD gives off septal and diagonal branches to the septum and left ventricular myocardium
• The Cx runs in the left atrioventricular groove
• The Cx gives off obtuse marginal branches to the posterolateral LV wall
• In 10% the Cx provides the posterior descending artery (PDA)

Question 24

The RCA runs in the right atrioventricular groove

Answer 24

Usually supplies sinus node, AV node and branches to the anterior RV wall

Question 25

Distal RCA branches into posterolateral and posterior descending arteries (latter in about 70% of people)

Answer 25

The posterior descending artery runs in the posterior interventricular groove and supplies inferior septum and LV

Question 26

Dominance refers to the artery (RCA or Cx) which supplies the posterior descending artery

Answer 26

Most people (70%) are right dominant – RCA supplies the PDA

About 20% are co-dominant – RCA and Cx both help supply the PDA

About 10% are left dominant – Cx supplies the PDA