Thorax 1.4

Question 1

How is the wall of the left and right ventricles different?

Answer 1

The muscular wall of the left ventricle is significantly thicker than the wall of the right ventricle

Question 2

What does the muscular wall of the left ventricle contain?

Answer 2

contains 2 papillary muscles whose chordae tendineae attach to the cusps of the mitral (left atrioventricular, or bicuspid) valve

Question 3

What are heart sounds occur from?

Answer 3

from the closing of the valves

Question 4

What is the first heart sound?

Answer 4

esults from the closing of the mitral and tricuspid valves

Question 5

What is the second heart sound?

Answer 5

the closing of the aortic and pulmonic valves

Question 6

What is mitral stenosis?

Answer 6

• Because of the pressures it must withstand, the mitral valve is most often involved in valvular heart disease.
  1. Mitral stenosis (narrowing) can impede the flow of blood from the left atrium to the left ventricle
  2. causing left atrial dilation

Question 7

What is mitral regurgitation?

Answer 7

• Mitral regurgitation (insufficiency) is often caused by
  1. abnormalities of the valve leaflets
  2. rupture or fibrosis of a papillary muscle
  3. or rupture of the chordae tendineae
• Stenosis or regurgitation causes turbulent blood flow and usually an audible murmur

Question 8

Where does oxygenated blood from the lung pass?

Answer 8

into the left atrium through 4 pulmonary veins (number can vary)

Question 9

What is the interventircular septum like?

Answer 9

• Most of the interventricular septum is muscular

- the uppermost portion is membranous and is a common site for ventricular septal defects

Question 10

What is the aortic vestibule?

Answer 10

The upper portion of the left ventricle, known as the aortic vestibule, is the outflow tract to the ascending aorta

Question 11

How many semilunar cusps are in the aortic valve?

Answer 11

3 (a semilunar valve)

Question 12

What is valvular heart disease?

Answer 12

1. can arise from a variety of conditions (stenosis, rupture of papillary muscles or chordae tendineae, malformed valve leaflets) 2. most often involves either the mitral or the aortic valves

Question 13

What is the major blood supply to the interventircular septum?

Answer 13

1. The major blood supply to the interventricular septum is via the left anterior descending branch of the left coronary artery 2. Ischemia of the interventricular septum may compromise the subendocardial (Purkinje) conduction system innervating the septum and ventricular walls.

Question 14

What is “Lub”?

Answer 14

The 1st heart sound (“lub”) is caused by closure of the tricuspid and mitral valves at the onset of ventricular systole

Question 15

What is “dub”

Answer 15

The 2nd heart sound (“dub”) is caused by closure of the aortic and pulmonary valves at the onset of ventricular diastole

Question 16

How many cusps are in the pulmonary valve?

Answer 16

it is a semilunar valve with 3 cusps

Question 17

Where can you hear the pulmonary valve the best?

Answer 17

Through the stethoscope, this valve is best heard over the left 2nd intercostal space, just lateral to the sternum

Question 18

Where can you head the closure of the aortic valve best?

Answer 18

Closure of this valve is best heard over the right 2nd intercostal space just lateral to the sternum

Question 19

How many valves does the mitral valve have?

Answer 19

The mitral (bicuspid, or left atrioventricular) valve has 2 cusps

Question 20

Where is closure of the mitral valve best heard?

Answer 20

Its closure at the onset of ventricular systole is best heard in the left 5th intercostal space, at the midclavicular line

Question 21

How many cusps does the tricuspid valve have?

Answer 21

The tricuspid (right atrioventricular) valve has 3 cusps. Its sound is best heard over the lower portion of the body of the sternum

Question 22

Where can you hear the sound of the tricuspid valve best?

Answer 22

sound is best heard over the lower portion of the body of the sternum

Question 23

What is the wall of the heart comprised of?

Answer 23

The wall of the heart is composed principally of cardiac muscle and a fibrous skeleton that provides attachment points for some of the cardiac muscle fibers and each heart valve

Question 24

What are hear valve leaflets?

Answer 24

avascular and receive their nutrients and oxygen by diffusion from the blood flowing through a valve

Question 25

What is the mediastinum?

Answer 25

the region between the 2 pleural cavities

Question 26

What divides the mediastinum?

Answer 26

A horizontal line through the sternal angle divides it into a superior and an inferior mediastinum

Question 27

What if the inferior mediatstinum divided into?

Answer 27

The inferior mediastinum is further divided into anterior, middle, and posterior compartments

Question 28

Where is the anterior mediastinum and what is in it?

Answer 28

• The anterior mediastinum lies just behind the body of the sternum and contains
  1. remnants of the thymus gland,
  2. lymph nodes
  3. fat
  4. some connective tissue

Question 29

Where is the middle mediastinum and what is in it?

Answer 29

• The middle mediastinum contains the
  1. pericardium
  2. heart
  3. nerves
  4. roots of the great vessels

Question 30

Where is the posterior mediastum and what is in it?

Answer 30

• The posterior mediastinum is posterior to the pericardium and heart
• It contains the
  1. esophagus
  2. thoracic aorta
  3. azygos system of veins
  4. thoracic lymphatic duct
  5. and nerves

Question 31

What happens with left atrial enlargement?

Answer 31

• Note the close relationship of the esophagus to the left atrium
  1. With left atrial enlargement, this heart chamber can expand posteriorly and partially constrict the esophagus
  2. Posterior to the esophagus lies the thoracic lymphatic duct, which ultimately drains lymph into the venous system at the junction of the left internal jugular and left subclavian veins