Cardiac Anatomy And Physiology

Question 1

AV Annulus

Answer 1

Where valve cusps attach to aortic root

Question 2

Commissures

Answer 2

Where adjacent cusps meet

Question 3

Lambl’s Excrescences

Answer 3

Small mobile filaments arising from edge of ventricular surface of cusp of AV

No clinical significance–do NOT confuse with vegetation or papillary fibroelastoma

Question 4

Nodule of Arantius

Answer 4

Small nodule at centre of cusp of AV - more prominent in older patients

Question 5

Coronary Sinuses

Answer 5

RCC = RCA
LCC = LCA
NCC

Question 6

MV Leaflets

Answer 6

Anterior and Posterior Leaflets
A1-A3 and P1-P3 (Antero lateral Commissure A\P 1 - Posteromedial Commissure A\P3)
Anterior leaflet almost touches IVS

Question 8

Function of Chordae Tendinae

Answer 8

chordae keep the mitral leaflets under tension during systole, preventing prolapse of the leaflets back into the LA.

Question 9

2 Papillary Muscles

Answer 9

anterolateral and posteromedial (after the location of their attachment to the LV), and which are attached to the mitral leaflets via the chordae tendineae.

Each supply all Chordae

Question 12

3 Groups of Chordae Tendinae

Answer 12

they are categorized into three groups:
first order or marginal chordae, which attach to the free edges of the mitral leaflets
second order or strut chordae, which attach to the ventricular surface of the leaflets (away from the free edges)
third order or basal chordae, which run directly from the ventricular wall (rather than the papillary muscles) to the ventricular surface of the posterior leaflet, usually near the annulus.

Question 13

Coaptation and Apposition

Answer 13

Coaptation: closing of Leaflets
Apposition: overlap of leaflet tips

Question 14

First Order Chordae

Answer 14

first order or marginal chordae, which attach to the free edges of the mitral leaflets

Question 15

Second Order Chordae

Answer 15

second order or strut chordae, which attach to the ventricular surface of the leaflets (away from the free edges)

Question 16

Third Order Chordae

Answer 16

third order or basal chordae, which run directly from the ventricular wall (rather than the papillary muscles) to the ventricular surface of the posterior leaflet, usually near the annulus.

Question 17

LA Anatomical location

Answer 17

Back of heart, anterior to oesophagus

Question 18

Focus for thrombus formation

Answer 18

LAA

Question 20

Eustachian Valve

Answer 20

embryological remnant, may be seen in the rA near the junction with the inferior vena cava

Question 21

Tricuspid valve cusps

Answer 21

three cusps –in order of decreasing size, these are called the anterior, posterior and septal cusps.

Question 22

PV Cusps

Answer 22

valve itself is structurally similar to the aortic valve, having three cusps (called anterior, left and right).

Question 23

LA Contraction

Answer 23

LA is not just a passive conduit between the pulmonary veins and the LV, but contracts during atrial systole (immediately after the onset of the P wave) to provide additional diastolic filling of the LV (the ‘atrial kick’).

Question 27

Ventricular filling phase

Answer 27

begins as the mitral valve opens and blood flows into the LV from the LA.
this phase ends when the mitral valve closes at the start of ventricular systole.
towards the end of the ventricular filling phase, atrial systole (contraction) occurs, coinciding with the P wave on the ECG, and this augments ventricular filling.

Question 28

Layers of Pericardium

Answer 28

there is an outer fibrous layer –the fibrous pericardium –which blends with the diaphragm inferiorly, and an inner layer –the serous pericardium –which itself has two layers (the parietal pericardium, continuous with the fibrous outer layer, and the visceral pericardium, which is the epicardium of the heart).

Question 29

Isovolumic Relaxation phase

Answer 29

commences with AV closure
Pressure within the LV falls during this phase (but volume remains constant), until the LV pressure falls below LA pressure.
At this point, the pressure difference between LA and LV causes the mitral valve to open and isovolumic relaxation ends.

Question 30

Gaps in Pericardium

Answer 30

pericardium contains ‘gaps’ where vessels enter and leave the heart, and the pericardium forms a small sleeve around these vessels. As a result, there is a small pocket of pericardium around the aorta/pulmonary artery (transverse sinus) and between the four pulmonary veins (oblique sinus).

Question 31

Moderator Band

Answer 31

stretches between the free wall and the septum in RV

Question 38

4 Phases of Cardiac Cycle

Answer 38

1. Isovolumic contraction
2. Ventricular Ejection
3. Isovolumic relaxation
4. Ventricular filling

Question 39

Phases of Cardiac Cycle in Systole and Diastole

Answer 39

Systole: phases 1 + 2
Diastole: Phases 3 + 4

Question 41

Isovolumic Contraction phase

Answer 41

MV closes
Increase ventricular pressure at start of systole as walls contract
Constant volume until AV opens

Question 42

Ventricular Ejection phase

Answer 42

AV Opens
Blood is ejected from LV to Aorta
LV Volume falls
Pressure rises until it peaks and then declines
Eventually pressure drops low enough and AV closes

Question 57

Normal RA Pressure (mmHg)

Answer 57

Mean 0-5mmHg

Question 58

Normal RV Pressure (SBP and DBP in mmHg)

Answer 58

Systolic 15-25mmHg

Diastolic 0-5mmHg

Question 59

Pulmonary Artery Pressure

SBP and DBP

Answer 59

Systolic 15-25 mmHg

Diastolic 5-12 mmHg

Question 60

LA Pressure (mmHg)

Answer 60

Mean 5-12 mmHg

Question 61

LV Pressure

Answer 61

SBP 100-140 mmHg

DBP 5-12 mmHg

Question 62

Normal Aortic Pressure

Answer 62

SBP: 100-140 mmHg
DBP: 60-90 mmHg

Question 63

S1

Answer 63

Closure of Mitral and Tricuspid Valves

Question 64

S2

Answer 64

Closure of aortic and pulmonary valve

Question 65

Physiologically Split S2

Answer 65

During expiration S 2 occurs as a single sound, but during inspiration the return of venous blood to the right heart makes the pulmonary valve close slightly later than the aortic valve, causing normal physiological splitting of S 2 with the pulmonary component (P2 ) occurring just after the aortic component (A2 ).

Question 66

Fixed Splitting S2

Answer 66

the presence of an ASD removes this respiratory variation in S 2 , so that the slight gap between A2 and P2 is there all the time (‘fixed splitting’).