CVS DR1: Mediastinum, Pericardium, Chambers of the heart

Question 1

What cavities are enclosed in the thoracic walls?

Answer 1

2 pleural cavities and the mediastinum

Question 2

How much of the thorax does the mediastinum contain?

Basic

Answer 2

Everything other than the lungs and their associated pleura

Question 3

What are the sections of the thorax?

Answer 3

Superior

Inferior:

• Anterior
• Middle
• Posterior

Question 4

What kinda important organ is NOT contained in the superior mediastinum?

Answer 4

The Heart

Question 5

What encloses the superior mediastinum, anteriorly and posteriorly?

Answer 5

Manubrium - Ant.

Vertebrae T1-T4 - Post.

Question 6

Which plane separates superior and inferior mediastinum?

Answer 6

Transverse

Question 7

What arteries are contained in the superior mediastinum?

Answer 7

Aortic arch

Brachiocephalic

Left Common Carotid

Left Subclavian

Question 8

What veins are contained in the superior mediastinum?

Answer 8

Brachiocephalic

Superior vena cava

Question 9

What major nerves pass through the superior mediastinum?

Answer 9

Vagus

Phrenic

Question 10

What other organs and structures are present in the superior mediastinum?

Answer 10

Trachea & Oesophagus

Thoracic duct - lymphatics

Thymus gland

Question 11

Describe the arrangement of the inferior pericardium, and it’s sections

Answer 11

Anterior section is the area between the sternum and the pericardium

Middle section is basically the pericardium

Posterior section is the area behind the pericardium

Question 12

What is in the anterior mediastinum?

Answer 12

Thymus - behind the sternum

Lymph nodes

Fat

Question 13

What is in the middle mediastinum?

Answer 13

Heart, pericardium

Great vessels

Question 14

What is in the posterior mediastinum?

Answer 14

Oesophagus & vagus nerve

Azygos vein

Descending aorta

Sympathetic trunk

Thoracic duct

Splanchnic nerve

Question 15

What are the 2 layers of the pericardium?

Answer 15

Fibrous & serous

Question 16

Describe the serous pericardia

Answer 16

Innermost of the Fibrous & serous pericardia

Composed of 2 layers with fluid filled cavity separating them:

• Parietal (outer) layer
• Visceral (inner) layer = epicardium

Question 17

Describe the fibrous pericardia

Answer 17

Outermost of the Fibrous & serous pericardia

Inner edge is in contact with parietal layer of serous pericardium

Question 18

From the outermost layer of the pericardium:

List the layers moving inwards, until the innermost layer of the heart

Answer 18

• Fibrous pericardium
• Parietal layer of serous pericardium

Pericardial cavity

• Visceral layer of serous pericardium = epicardium
• Myocardium
• Endocardium

Question 19

What are the main features of the right atrium?

Answer 19

3 Openings for:

• Inferior Vena cava
• Superior vena cava
• Coronary sinus

Interarterial septum

Fossa ovalis in Interarterial septum

Musculi pectinati & crista terminalis

Tricuspid valve

Question 20

What features would you look for to identify the right ventricle?

Answer 20

Tricuspid valve:

• 3 valve cusps
• Chordae tendineae
• Papillary muscles x3

Trabeculae carneae (contractile fleshy struts)

Moderator band (Septomarginal trabeculum)

1 Opening for pulmonary trunk

Interventricular septum

Question 21

What is the purpose of the Trabeculae carneae?

Answer 21

Most likely to prevent suction that would occur with a flat surface and thus impair the heart’s ability to pump efficiently. The papillary muscles themselves are just a specialised form of trabeculae carneae.

Question 22

What are the main features used to identify the left atrium?

Answer 22

4 Openings for:
l + r superior pulmonary veins
l + r inferior pulmonary veins

Bicuspid (mitral) valve

Smooth-walled, small chamber,
lying wholly postero-superiorly against
oesophagus.

Forms base of heart.

Question 23

What are the main identification features of the left ventricle?

Answer 23

Biscuspid (mitral valve):
2 valve cusps
Chordae tendineae
Papillary muscles x2

Trabeculae carneae

1 Opening for aorta

Interventricular septum

Wall 3x as thick as right ventricular wall.

Forms apex of heart

Question 24

Describe the vertebral level of the heart

Answer 24

T5-8

Middle 4 vertebrae^

(when in recumbent position)

Question 25

Where is the apex of the heart?

Answer 25

5th Left intercostal space In the midclavicular line

Question 26

What forms the base of the heart?

Answer 26

Left atrium This lies wholly posterior, and against the oesophagus

Question 27

What forms the right border of the heart?

Answer 27

Superior Vena cava & right atrium

Question 28

What forms the left border of the heart?

Answer 28

Aortic arch and left ventricle

Question 29

The surface anatomy 'area' of the heart is a weird box thing What forms each corner and where is it located on the surface?

Answer 29

Apex (bottom left) - 5th IC space in Midclavic. line Upper left - End of 2nd left rib, in line with Sternal angle Upper right - Intercostal cart of 3rd rib Bottom right - IC cartilage of 6th right rib, in line with bottom of body of sternum

Question 30

What are the main arteries located in the chest wall and trunk?

Answer 30

Descending aorta Internal thoracic artery: - This gives off branches of Anterior intercostal arteries

Question 31

What are the main veins of the chest wall and trunk?

Answer 31

Inferior vena cava Azygos vein Internal thoracic vein: - Receives anterior thoracic veins

Question 32

What lymph vessel would you look for in the chest wall and trunk? Where is this located?

Answer 32

Thoracic duct Runs just behind the Aorta

Question 33

What is the endocardium composed of?

Answer 33

Simple squamous epithelium sitting on basement membrane Sits on connective tissue

Question 34

What is the mycocardium made of?

Answer 34

Many layers of cardiac muscle (myocytes)

Question 35

What is the Epicardium (visceral serous) made of?

Answer 35

Simple squamous epithelium sitting on BM with connective tissue May have fatty layer separating it from the myocardium

Question 36

What is cardiac tamponade?

Answer 36

When excess fluid accumulates in the pericardial cavity (many reasons why this can happen) Increased pressure exerted by fluid onto the heart reduces the filling of the heart Can lead to cardiac failure if severe enough

Question 37

Describe the nervous innervation of the VISCERAL pericardium

Answer 37

Autonomic innervation from: - T1-T4 nerves - Vagus nerve via cardiac plexus (same as heart wall itself)

Question 38

Describe the nervous innervation of the Parietal and fibrous layers of the pericardium

Answer 38

Innervated mainly by the Phrenic nerve

Question 39

Which layers of the pericardium can detect pain?

Answer 39

Parietal layer of serous & the Fibrous layer They're innervated by phrenic whereas the visceral serous layer only receives autonomic innervation

Question 40

What nerves link to the cardiac plexus?

Answer 40

Vagus nerve (branches of) Nerves from Sympathetic trunk: - Middle cervical ganglion - Stellate ganglion - T2 - T3 - T4

Question 41

What chamber of the heart contains the fossa ovalis? What is it?

Answer 41

Contained in the right atrium Remnant of the foramen ovale which closes after birth Was basically a passage from the right to left atria to avoid the pulmonary circulation which the foetus did not need when in the womb

Question 42

The right atrium has an 'auricle' What is this?

Answer 42

Flappy bit at the top of the atrium

Question 43

What separates the two atria?

Answer 43

Interatrial septum

Question 44

What is the name of the bumpy, pure stringy muscle section on the walls of the atria?

Answer 44

Musculi pectinati

Question 45

What is the name given to the large ridge/bump thing that is found at the end of the musculi pectinati?

Answer 45

Crista terminalis | crista sort of means ridge

Question 46

What is the correlation between the number of cusps in a valve, and the number of papillary muscles in the ventricle

Answer 46

For each cusp, there is one papillary muscle attached to it

Question 47

The moderator band (septomarginal trabeculum) is found in the right ventricle. What is it's function?

Answer 47

It carries the right bundle branch from the AV node to the papillary muscles in the RV This means contraction of papillary muscles is coordinated with heart contraction, meaning the valve doesn't invert

Question 48

What is the difference between Musculi pectinati and trabecullae carnae?

Answer 48

They have the same appearance, columned, stringy walls of muscle However, the Musculi P are only in the atria and the Trabecullae C are only in the ventricles

Question 49

What valve separates the left ventricle and left atrium?

Answer 49

Mitral valve | bicuspid