Week 2- Anterior mediastinum Flashcards

1
Q

How can the mediastinum be divided?

A

Into superior and inferior.

Inferior can be further divided into anterior, middle and posterior.

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2
Q

What separates the superior and inferior mediastinum?

A

Transverse thoracic plane- runs from the sternal angle to the T4/5 intervertebral disc.

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3
Q

What are the boundaries of the anterior mediastinum?

A

Anteriorly- body of sternum
Posteriorly- pericardium
Superiorly- transverse thoracic plane
Inferiorly- diaphragm.

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4
Q

What can be found in the anterior mediastinum?

A

Loose connective tissue
Fat
Lymphatics

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5
Q

What might be found in children in the anterior mediastinum that may not be present in adults?

A

The thymus as its larger in children and may extend down into the anterior mediastinum.

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6
Q

What is contained in the middle mediastinum?

A

The heart and pericardium

Roots of the great vessels.

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7
Q

Which nerve is associated with the pericardium of the heart?

A

The phrenic nerve.
On the right it runs over the pericardium over the right atrium. On the left it runs over the pericardium over the atrium and ventricle.

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8
Q

What does the fibrous pericardium blend with superiorly?

A

The tunica adventitia of the great vessels.

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9
Q

What does the fibrous pericardium blend with inferiorly?

A

The central tendon of the diaphragm.

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10
Q

Describe the layers of the pericardium

A

Fibrous pericardium- outer layer

Serous pericardium- divided into two layers parietal serous pericardium and visceral pericardium.

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11
Q

What lies deep to the visceral serous pericardium?

A

Lots of fatty deposits.

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12
Q

What is the visceral serous pericardium also known as?

A

The epicardium.

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13
Q

What layers of the heart lie below the epicardium?

A

Myocardium- muscle layer

Endocardium

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14
Q

What is the transverse pericardial sinus and what is its significance?

A

The heart starts of as a tube in a pericardial sac. As it starts to develop it folds in on itself leaving a layer of pericardial sac within the heart. This separates the great vessels.

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15
Q

Where would you find the oblique pericardial sinus?

A

Space underneath and behind the heart.

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16
Q

Which chamber of the heart makes up the inferior border?

A

Right ventricle.

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17
Q

Which chamber of the heart makes up the apex?

A

Left ventricle.

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18
Q

Which chamber of the heart makes up the right border?

A

The right atrium

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19
Q

What chamber of the heart makes up the left border?

A

Left ventricle and auricle.

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20
Q

What are the three branches of the aorta?

A

1st - brachiocephalic trunk
2nd- left common carotid
3rd- left subclavian

21
Q

What is the ligamentum arteriosum

A

A fibrous remnant of the ductus arteriosus.

Allowing communication between the aorta and pulmonary trunk.

22
Q

Which nerve is closely associated with the ligamentum arteriosum?

A

Left recurrent laryngeal nerve runs posterior to it in an adult.

23
Q

Which artery supplies the SA node?

A

The SA nodal branch of the right coronary artery.

24
Q

Which artery supplies the AV node?

A

The AV nodal branch of the right coronary artery.

25
Q

Describe the branches and path of the right coronary artery.

A

Starts at the root of the aorta. It descends down and gives off the SA nodal branch.
It splits at the inferior border of the heart to give off the right marginal artery.
It then goes onto the posterior surface of the heart forming and gives off the posterior inter ventricular artery branch and the AV nodal branch.

26
Q

Describe the branches and path of the left coronary artery?

A

Starts at the root of the aorta.
Immediately bifurcates to form the left anterior descending and left circumflex.
The left circumflex on the left border of the heart then splits to form the left marginal which goes along the left border, while the circumflex continues onto the posterior aspect of the heart.

27
Q

What does the right coronary artery supply?

A

The right atrium and most of the right ventricle.
SA and AV nodes
Posterior 1/3rd of the IV septum
Part of the left ventricle.

28
Q

What does the left coronary artery supply?

A

Left atrium and most of the left ventricle.
Anterior 2/3rds of IV septum
AV bundle
Part of R ventricle.

29
Q

Where do all the veins of the heart drain into (with 1 exception- what is this)?

A

Drain into the coronary sinus

Except the anterior cardiac veins which drain directly into the right atrium.

30
Q

Where is the coronary sinus located?

A

At the junction between the left atrium and left ventricle.

31
Q

What vein is continuous with the coronary sinus?

A

The great cardiac vein.

32
Q

Describe the openings in the right atrium?

A

Openings for SVC and IVC and for the coronary sinus.

33
Q

What are the muscular ridges in the walls of the atria called?

A

Musculi pectinae.

34
Q

What is the fossa ovalis?

A

Remnant of foramen ovale (allowed communication between the left and right atrium).

35
Q

What is the crista terminale?

A

Seperates the smooth and muscular portion of the atria.

36
Q

What structure is unique to the right ventricle? What is its function?

A

The moderator band.

Allows a ‘short cut’ for the conducting system of the heart.

37
Q

What valve lies between the right atrium and the right ventricle?

A

The tricuspid valve.

38
Q

What are the muscular ridges in the ventricles called?

A

Trabeculae carnae.

39
Q

What muscles are associated with the tricuspid valve? How do they connect to the valve?

A

Papillary muscles.

Connect via chordae tendinae.

40
Q

How many cusps does the mitral valve have?

A

2 cusps (bicuspid)

41
Q

What indentations does the left atrium have in its walls?

A

Left atrium is smooth walled. However it has indentations where the fossa ovalis is.
It also has four holes for the pulmonary veins.

42
Q

During high pressure, which types of valves will remain closed?

A

Cuspid valves (e.g. tricuspid and mitral)

43
Q

During low pressures, which types of valves will remain closed?

A

Semilunar valves.

44
Q

How are the coronary arteries filled?

A

Backflow of blood down the aorta fills the spaces beside the valves causing them to close, but also simultaneously fills the CA’s.

45
Q

During diastole- which valves are open?

A

The tricuspid and mitral valves are open and the aortic and pulmonary valves are closed.

46
Q

During systole- which valves are open?

A

The pulmonary and aortic valves are open and the tricuspid and mitral vavles are open.

47
Q

What is the function of the fibrous skeleton of the heart?

A

Supports the valves and provides electrical insulation between the atria and ventricles.

48
Q

What innervates the SA node?

A

Autonomic innervation via the cardiac plexus.
Sympathetics- increase HR- T1-T5/6 spinal levels. Via the cervical and superior thoracic paravertebral ganglia.
Parasympathetics- decrease HR- vagus nerve.