CVS

Question 1

Where is the apex beat palpated?

Answer 1

left 5th intercostal space, mid-clavicular line

Question 2

what is the anterior surface of the heart formed mainly by?

Answer 2

right ventricle

Question 3

what is the inferior surface of the heart mainly formed by?

Answer 3

left ventricle

Question 4

what is the apex of the heart mainly formed by?

Answer 4

left ventricle

Question 5

what is the posterior surface of the heart mainly formed by?

Answer 5

mainly left atrium and pulmonary veins

Question 6

what is the mediastinum?

how is it divided?

Answer 6

the area between the right and left pleura.

divided into:
superior and inferior by plane between sternal angle and T4/5

anterior, middle and posterior by pericardium

Question 7

describe the pericardium

• function
• components
• innervation

Answer 7

Layers of connective tissue functioning as protection for the heart -, providing a friction-free surface for the heart to accommodate its sliding movements - this is aided by pericardial fluid.
Layers:
- Fibrous layer: Collagenous outer layer. Fused with central tendon of the diaphragm. Anchors heart to the mediastinum and protects from damage
Serous layers - divided into two layers, continuous at the aorta(‘fist in balloon’):
- parietal - lines the inner surface of the fibrous layer
- visceral - lines the outer surface of the heart

Potential space between the 2 serous layers = pericardial space.

Innervation = phrenic nerves

Question 8

what does ‘cardiac tamponade’ refer to?

Answer 8

pericardial space fills with pericardial fluid - usually drained from the left of the xiphisternum, allowed by pleural reflection

Question 9

what can often be inferred by impaired function of an atrioventricular valve?

Answer 9

disorder of relevant ventricle

Question 10

how are atrioventricular valves (mitral and tricuspid) attached to their relevant ventricle?

Answer 10

intrinsic part of their ventricle.
Papillary muscles (part of ventricle) attach to atrioventricular valves via fibrous cords called chordae tendinae.
Anchored on the annulus fibrosis cordis, ring of fibrous tissue.

Question 11

What are cardiac valves composed of?

Answer 11

Intrinsic part of their relevant ventricle (atrioventricular) or great artery (semilunar) - composed ofconnective tissue and endocardium (the inner layer of the heart).
All anchored on annulus fibrosis cords, ring of fibrous tissue.

Question 12

How do the tricuspid and mitral valves differ?

Answer 12

Tricuspid: located between the right atrium and the right ventricle. Consists of three cusps (anterior, septal and posterior). Connected to trabecular carneae muscles via chordae tendineae
Mitral: located between the left atrium and the left ventricle. Has two cusps (anterior and posterior). Connected to papillary muscles via chordae tendineae

Question 13

all heart valves have 3 cusps except

Answer 13

mitral valve

Question 14

what is the role of the pulmonary artery?

Answer 14

carries deoxygenated blood from the heart to the lungs

Question 15

what is the role of the pulmonary veins?

Answer 15

carry oxygenated blood to the heart from the lungs

Question 16

how do the left and right ventricles differ?

Answer 16

left is thicker and more muscular - it is the systemic ventricle.

Question 17

From which vessels does blood drain into the left atrium?

Answer 17

from 4 pulmonary veins

Question 18

what is the role of the coronary sinus?

Answer 18

drains deoxygenated blood blood from the heart muscle into the right atrium

Question 19

describe the structure of the right atrium

Answer 19

smooth part (from sinus venosus) and rough ‘trabeculated’/musculi pectinate part (from original atrium). Crista terminalis separates smooth and trabeculated portions of right atrium.
Musculi pectinate has paralel ridges in walls. Allows strong contraction with minimal muscle mass.
Embryonic remnants:
- fossa ovalis, depression of interatrial wall, is remnant to foramen ovale.
- right atrial appendage pumps blood into ventricle during systole

Question 20

what is the border between the RA and RV on the surface of the heart?

Answer 20

the right atrioventricular sulcus - occupied by the right coronary artery.

Question 21

describe the structure of the R ventricle

Answer 21

has muscular ridges called trabeculae carneae which increase contractile strength.
Septomarginal trabeculum is muscular band of tissue that carries part of the R bundle branch of His to anterior papillary muscles, reducing conduction time..

Question 22

describe the structure of the LA

Answer 22

Separated from the left ventricle by the left atrioventricular sulcus, occupied by the left coronary artery.
Left auricular appendage is foetal remnant, expansion allows increased collecting and pumping of blood capacity.

Question 23

Describe the structure of the tricuspid valve

Answer 23

3 flaps of connective tissue.
Connected to trabeculae carneae muscles via chordae tendineae (bands of connective tissue)
These prevent inversion of the valves and backflow

Question 24

How do semilunar valves differ from atrioventricular?

Answer 24

-Passive: When ventricles contract the pressure is greater in
ventricle and so valve opens
Structure means that when the pressure is greater in the artery the valve is closed.
Meanwhile atrioventricular are connected to muscles of ventricle muscle via chordae tendineae, preventing valve inversion and back flow.

Question 25

Describe the blood supply of the heart.
Emergence?
Drainage?

Answer 25

Epicardial coronary arteries supply the heart. This means they are accessible to surgeons .
The left and right coronary arteries emerge at the aortic sinus and are drained by cardiac veins..

Functional end arteries - only supply of oxygenated blood to the heart, meaning an occlusion completely cuts off O2 to heart,

Question 26

Describe the journey of the right coronary artery?

Answer 26

Arises from the anterior aortic sinus
Passes between pulmonary trunk and RA in the right atrioventricular groove.
Winds round the inferior border to reach the diaphragmatic surface where it amitoses with the terminal part of the L coronary artery. Lateral branches - marginal arteries.
Then forms the PDA artery in 70% of people, which runs in the posterior inter ventricular groove.

Question 27

How does the path of the right posterior descending artery differ in the population?

Answer 27

Different vessels give rise to the posterior descending artery:
70%: right dominant where the PDA is supplied by the RCA.
20% codominant: RCA and left circumflex artery both supply the PDA
10%: Left dominant: left circumflex artery supplies the PDA.
for 60% of people, the SA nodal artery is a branch of the coronary artery - for 40%, it is a branch of left circumflex.

Question 28

What do the branches of the R coronary artery supply?

Answer 28

• R marginal: RV
• SA nodal( a branch from the RCA for 60% people): SAN and surrounding myocardium
• AV nodal: AVN and surrounding myocardium
• R posterior descending: RV, LV, IV septum

Question 29

What do the branches of the Left coronary artery supply?

Answer 29

Circumflex: posterior surface of LV. Branches into Left marginal which supplies LV, and, in 40% people, the SA nodal artery, supplying the SAN and surrounding myocardium.
Anterior descending artery supplies the RV, LV and IV septum

Question 30

Where does the left anterior descending artery run and what branches does it give off?

Answer 30

Runs in the anterior inter ventricular groove, gives off septal and diagonal branches to the septum and left ventricular myocardium.

Question 31

Where does the left circumflex artery run and what branches does it give off?

Answer 31

Left atrioventricular groove. Gives off obtuse marginal branches to the posterolateral LV wall. In 10% of people, supplies the PDA.

Question 32

Describe the venous return of the heart

Answer 32

Collected by the cardiac veins which roughly follow the path of the coronary arteries and converge to form the coronary sinus in the coronary sulcus, which opens into the RA just about the inferior vena cava.
All tributaries drain into the coronary sinus except the anterior vein which drains blood directly into the RA.

Question 33

Where do these tributaries of the cardiac sinus run and what do they drain?

Great cardiac vein
Middle cardiac vein
Small cardiac vein

Answer 33

• Great cardiac vein: begins at the cardiac apex, runs in the anterior inter ventricular sulcus along with the LAD. Drains area of heart supplied by LCA - LV and RV and LA
• Middle cardiac vein: follows R posterior descending branch of RCA, drains areas supplied by PD artery: RV, LV, IV septum
• Small cardiac vein: runs in the posterior atrrioventricular groove and opens into the coronary sinus near its atrial end. Drains posterior RA and RV.