Part 6: Middle Mediastinum and Heart Flashcards

1
Q

Describe the layers of pericardium

A

Fibrous pericardium: encloses heart and great vessels - fuses with them all except IVC.
Serous pericardium: Has 2 layers - parietal and visceral

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2
Q

What are the oblique and transverse sinuses?

A

Oblique sinus: cul-de-sac between 2L and 2R PVs and the IVC

Transverse sinus: Communication from R to L between PAs and PVs

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3
Q

What is the nerve and blood supply of the pericardium?

A

Blood:
pericardiocophrenic and internal thoracic
N: Phrenic nerve

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4
Q

How is the fibrous pericardium attached to surrounding structures?

A

Overlies central tendon of diaphragm. Fibrous sac is connected to upper and lower ends of sternum by weak sternopericardial ligaments

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5
Q

What anatomical structures make up the right, left, inferior, anterior and posterior surfaces (ie as seen in CXR)

A

R: entirely RA
L: mostly LV with some auricle LA
Inferior border: mostly RV with small portion LV (apex)
Anterior: RA, vertical AV groove, RV with narrow strip LV
Diaphragmatic surface: RA, AV groove, 1/3 RV 2/3 LV
Posterior: LA

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6
Q

Describe the fibrous skeleton

A

A + V are attached to pair conjoined fibrous rings which form figure while binding AV orifices. Atria lie to right and ventricles to left of fibrous skeleton with no muscular continuity between them

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7
Q

How are valves and interventricular septum related to the fibrous skeleton?

A

Membranous part of septum fuses with skeleton.

Bases of cusps of tricuspid and mitral are attached to skeleton

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8
Q

How many venous openings does the RA have?

A

IVC
SVC
Coronary sinus

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9
Q

Describe the difference between smooth and rough wall in RA?

A

Smooth to the right of crista terminalis
Between crista and the ending of auricle the myocardium is projected into by horizontal ridges of muscles - pectinate muscle

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10
Q

Where is the fossa ovalis?

A

Interatrial septum forms posterior wall of RA. In lower part is shallow depression of fossa ovalis

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11
Q

What are the muscle ridges of the RV called?

A

Trabeculae carnea

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12
Q

What forms papillary muscles and the septomarginal trabeculae?

A

Trabeculae carneae. Papillary muscles are attach to cusps of valve. Septomarginal trabeculae attaches lies in cavity and attaches to interventricular septum and anterior papillary muscle.

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13
Q

What are the cusps to the pulmonary valve?

A

anterior, L + R

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14
Q

What are the 3 cusps to tricuspid valve?

A

Anterior, posterior and septal

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15
Q

What are the venous openings into the LA?

A

4 pulmonary veins

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16
Q

Is the LA smooth or muscular?

A

Smooth except for auricle - this is because smooth parts originate from pulmonary veins and rough part from heart

17
Q

What are the cusps of mitral valve?

A

anterior and posterior

18
Q

What are the cusps of aortic valve?

A

posterior, L + R

19
Q

What is the difference in structure between AV valves and aortic/pulmonary valves?

A

TV+MV: free edges with serrated outline. Integrity requires contraction and pull of chordinae tendonae
PV+AV: free edge with central fibrous nodule, integrity being passive

20
Q

Microscopically what are valves composed of?

A

Fibrous tissue with elastic fibres. Covered by vascular endothelium.

21
Q

What are the surface markings of valves?

A

All lie behind sternum, almost in vertical plane. Tricuspid -> mitral -> aortic -> pulmonary
This is different for auscultation as this is dependent on blood filled chambers being close to chest wall

22
Q

What is the SA node?

A

Specialised muscle fibres - contains P cells and generates impulses for contraction. Lies below SVC into L wall of RA.

23
Q

What is the path of the cardiac action potential?

A

SA -> atrial muscles fibres -> AV node -> AV bundle -> R + L -> Subendocardial purkinje fibres

24
Q

Where does AV node lie?

A

Interatrial septum. Above and to left of opening of coronary sinus

25
Q

Blood supply of heart - ride side supply

A

RCA -> passes between auricles then vertically down the posterior

26
Q

Describe the left side blood supply of heart

A

LCA arises behind pulmonary trunk. passes between left auricle and RV. Divides into 2 branches - Circumflex to back of heart and anterior interventriclar down IV groove to anastomose with posterior IV branch

27
Q

What supplies the SA node?

A

60% RCA

40% LCA

28
Q

Describe the venous drainage of heart

A
  • venae cordis minimus: small veins of walls of heart open into all 4 chambers respectively. Only make up small % of venous drainage.
  • anterior cardiac veins: drain directly to RA
  • Great cardiac vein: main vein, drains into coronary sinus
29
Q

What is the lymph drainage of heart?

A

Follows arterial system along aorta and pulmonary trunks

30
Q

What is nervous supply of heart?

A

Cardiac plexus