Anatomy - Internal Heart and Posterior Mediastinum

Question 1

What do the coronary arteries supply?

Answer 1

Supply heart muscle

Question 2

Where does left and right coronary arteries arise from?

Answer 2

Ascending aorta (from aortic sinus)

Question 3

What are the major branches of the LCA?

Answer 3

1. Circumflex artery 2. Anterior interventricular artery (left descending artery)

Question 4

What branch does the left circumflex artery give off?

Answer 4

Marginal artery

Question 5

What branch does the left anterior interventricular artery give off?

Answer 5

Diagonal branch

Question 6

What are the branches of the right coronary artery?

Answer 6

1. Marginal artery
2. Posterior interventricular artery

Question 7

What does the pulmonary trunk give rise to?

Answer 7

Right and left pulmonary arteries (travel to lungs)

Question 8

What is the auricle of the heart?

Answer 8

One on left and right –> a flap of heart wall on the anterior surface of the left/right atrium

Question 9

What is the heart drained by?

Answer 9

Coronary veins

Question 10

Where do the majority coronary veins drain into?

Answer 10

Coronary sinus which then travels to right atrium

Question 11

What is the fossa ovalis?

Answer 11

Remnant of shunt (foramen ovale) between right and left atrium

Question 12

What forms the rough part of the atrial wall?

Answer 12

Pectinate muscles

Question 13

What is the smooth and rough part of the atrial wall separated by?

Answer 13

Crista terminalis –> musclar ridge separating elevations from smooth part

Question 14

Where do smooth and rough parts of atrial wall come from?

Answer 14

Different embryological origins

Question 15

Why is the left atrium smoother than the right?

Answer 15

As pulmonary veins have been encompassed into the left atrial wall

Question 16

What is function of chordae tendinae?

Answer 16

Attach to edge of cusps and achor valves to ventricular wall

Question 17

What are the chordae tendinae held in place by?

Answer 17

Papillary muscles

Question 18

Where are papillary muscles found?

Answer 18

Ventricle

Question 19

What are papillary muscles?

Answer 19

Elevations from trabeculae carnae (roughened musculature of ventricles)

Question 20

What are trabeculae carnae?

Answer 20

Roughened musculature of ventricles

Question 21

Are trabeculae carnae more prevalent in right or left ventricle?

Answer 21

Left

Question 22

Describe action of papillary muscles

Answer 22

Contract to prevent tricuspid / bicuspid valve from prolapsing back into right /left atrium during diastole

Question 23

Which valves have 3 leaflets? Which have 2?

Answer 23

2 –> mitral valve/bicuspid (AV valve on right)

3 –> tricuspid (AV valve on left), aortic valve, pulmonary valve

Question 24

What is the tricuspid valve held in place by?

Answer 24

By chordae tendinae which are pulled taught by papillary

3 cusps –> 3 papillary muscles

Question 25

What is the conus arteriosus?

Answer 25

the upper front part of the right ventricle of the heart from which the pulmonary trunk arises

Question 26

Is the conus arteriosus smooth or muscular?

Answer 26

Smooth (outflow tract)

Question 27

What is the moderator band? Where does it go from/to? How does it work?

Answer 27

From interventricular septum towards papillary muscles.

Role in cardiac cycle: Just before impulse from SA node causes ventricular systole, there is some nervous tissue/Purkinje fibres that project through moderator band to papillary muscles a millisecond before ventricular systole.

Question 28

What is function of moderator band?

Answer 28

Papillary muscles contract and pull on chordae tendinae to keep tricuspid valve open during ventricular systole (stop from prolapsing back into atria)

Question 29

Describe shape of left ventricle during contraction

Answer 29

Circular

Question 30

Describe shape of right ventricle during contraction

Answer 30

• More triangular in shape
• When contracts, compresses against muscular wall of left ventricle

Question 31

As the trachea bifurcates, what does the left primary bronchus cross and cause a constriction of?

Answer 31

Oesophagus (located behind it)

Question 32

Does the trachea pass posterior or anterior to the aorta?

Answer 32

Posterior

Question 33

Where does the trachea bifurcate?

Answer 33

Left of carina, T4/T5

Question 34

What does the azygos vein drain?

Answer 34

Posterior intercostal veins

Question 35

Where does the azygos vein empty into?

Answer 35

Superior vena cava

Question 36

What does thoracic duct drain?

Answer 36

Drains all lymph from lower half of body

Question 37

Where does thoracic duct empty into?

Answer 37

Empties into venous system

Into left venous angle where subclavian vein and jugular vein merge to form brachiocephalic vein

Question 38

What can damage to thoracic duct lead to?

Answer 38

Lymph in thoracic cavity –> chylothorax

Question 39

What is chyle?

Answer 39

Lymph formed in the digestive system –> taken up by lymph vessels specifically known as lacteals

Question 40

Where is the azygos vein located?

Answer 40

On right of vetebral column

Question 41

Where is the thoracic duct located?

Answer 41

The thoracic duct ascends through the aortic hiatus of the diaphragm entering the posterior mediastinum, still to the right of the vertebral column. It courses posterior to the esophagus at the T7 level and crosses over the midline to the left side of the thorax around the T5 vertebral level.