Heart 2: internal heart, valve and nerves

Question 1

What are the two parts of the right atrium?

Answer 1

1x : smooth walled where the SVC, IVC and coronary sinus drain into

1x : muscular wall that contracts, made of pectinate muscles (look like a comb)

**R. auricle also has muscular walls

Question 2

What is the crista terminalis

Answer 2

Boundary between the smooth and muscular walls of the right atrium

Question 3

What is the structure of the mitral and tricuspid valves?

Answer 3

Papillary muscles within the ventricular walls anchor cusps via ‘chordae tendinae’. The cusps are attached at the ‘cuff’

Question 4

Another name for the ‘moderator band’ and where is it found?

Answer 4

‘Septomarginal trabecula’

A band of muscle in the R ventricle

Question 5

Role of the moderator band?

Answer 5

1) When the ventricles contract, MB acts as a shortcut from the inter-ventricular septum across the anterior wall of the septum. This allows the electrical impulse to reach the anterior wall at the same time as the rest of the ventricle (inc efficiency = decr fractional difference)
2) Also means papillary muscles contract just a little bit sooner then the rest to stop the valve going backwards, preventing ‘flowback’ into the atrium

Question 6

Describe the Left atrium

Answer 6

An incredibly thin-walled ‘collecting space’. The only muscular part is the left auricle

Question 7

Whats the difference in the ventricular walls and why?

Answer 7

Left ventricle is 3x thicker as it’s pushing against the higher systemic circulation pressures.

Question 8

Draw the heart valves

Answer 8

…

Question 9

stenosis

Answer 9

narrowing or growth that stops blood flow

Question 10

Regurgitation

Answer 10

Valves don’t close properly and blood flow is backwards

Question 11

Draw the surface projection of heart valves. Why do these matter

Answer 11

Because we hear best where the blood is rushing to

Question 12

Aortic valve is best heard at the…

Answer 12

2nd intercostal space, at the right parasternal edge

Question 13

Pulmonary valve is best heard at the…

Answer 13

2nd intercostal space, at the left parasternal edge

Question 14

Mitral valve is best heard at..

Answer 14

5th intercostal space, midclavicular line, at the apex of the heart

Question 15

Tricuspid valve is best heard at..

Answer 15

Left sternal edge of the 5th intercostal space

Question 16

Conduction pathways of the heart

Answer 16

1) Sinoatrial node (impulse generated)
2) Atrioventricular nod
3) Atrioventricular bundle of His
4) Right and left bundle branches
5) Purkinje fibres (subendocaridal branches)

Question 17

Left and right coronary arteries open into the ____, what does this mean?

Answer 17

Open into the aorta, and in systole are blocked by the aortic valves.
Therefore these fill in diastole when the aortic valves drop down and blood is forced in.
This is the ONLY diastolic filling!!

Question 18

Is the left or right coronary artery more important? Treatment for issues?

Answer 18

RCA: supplies SA node, AV node so without > rhythm disturbances

LCA: supplies LAD > supplies left ventricle > pump failure/issues

Treatment: angioplasty, CA bypass

Question 19

how does the cardiac plexus form?

Answer 19

Sympathetic trunks (T1-5) > Sympathetic fibres > PLEXUS