CVM - Lecture 1: Mediastina, Lymph and Nerve Supply

- right common carotid artery

- right subclavian artery

What arises from the brachiocephalic trunk?

the parietal pleura

What makes up the lateral borders of the middle mediastinum?

sup: 2nd rib

inf: 5th intercostal space

At what level are the superior and inferior borders of the heart?

Fibrous pericardium

parietal (serous) pericardium

visceral (serous) pericardium

What are the layers of the pericardium from superficial to deep?

The visceral pericardium

Which layer does the epicardium refer to?

The musclular middle layer of the heart wall

What is the myocardium?

The epithelial inner lining of the heart, continuous with the endothelium

What is the endocardium?

1. Left common carotid A.

2. SVC

3. phrenic nerve

4. pericardiophrenic vessels

5. diaphragm

Fill the blanks

Superior Vena Cava +Inferior Vena Cava -> Right atrium -> Right ventricle -> Pulmonary arteries -> Capillary bed of lungs -> Pulmonary veins -> Left atrium -> Left ventricle -> Aorta+branches

List the order of the cardiac circuit from the greatest vein to the greatest artery

1. aortic arch

2. SVC

3. fossa ovalis

4. IVC

5. Valve of IVC

6. Valve of corona sinus

7. aperture of coronary sinus

8. auricle

9. limbus of fossa ovalis

10. crista terminalis

11. pectinate muscles (musculi pectinati)

Fill the blanks

This was previously the foramen ovalis - an embryonic shunt between the two atria to bypass pulmonary circuit

What is the role of the fossa ovalis?

the tricuspid valve

What separates the RA and the RV

- cusps: anterior, septal, posterior

- chordae tendinae

- papillary muscles

- septomarginal trabecula

What makes up the tricuspid valve?

These are the muscles of the ventricular wall

What is the function of the trabeculae carnae?

Pulmonary valve: anterior+right+left semilunar cusps

What separates the right ventricle from the pulmonary trunk?

1. anterior cusp

2. septal cusp

3. posterior cusp

4. anterior semilunar cusp

5. right semilunar cusp

6. left semilunar cusp

7. chordae tendineae

8. anterior papillary muscle

9. trabeculae carneae

10. posterior papillary muscle

11. septomarginal trabecula

12. septal papillary muscle

Fill the blanks

1. pulmonary arteries

2. pulmonary veins

3. valve of foramen ovale

4. bicuspid (aka mitral) valve

4

How many pulmonary veins are there?

- anterior cusp

- posterior cusp

Name the cusps of the mitral valve

1. coronary sinus

2. anterior cusp

2b. posterior cusp

3. cordae tendinae

4. anterior papillary muscles

5. posterior paipllay muscles

6. trabeculae carnae

Fill the blanks

The aortic (semilunar) valve

What separates the left ventricle from the aorta?

- left seminlunar valve

- right semilunar valve

- posterior aortic valve

What are the cusps of the aortic valve?

active: atrioventricular valves

passive: semilunar valves

Which are the active and passive valves of the heart respectively?

- a septum separates the right and left sides physically and electrically

- 4 connective tissue rings support the valves

Describe the major fibrous structures that allow the heart to function

1. atria contract (late diastole)

2. ventricles relax and fill

3. AV valves open with papillary muscles

4. semilunar valves are shut

In diastoli, describe the activity of the: 1. atria 2. ventricles 3. AV valves 4. semilunar valves

1. atria are relaxed and fill

2. ventricles contract

3. AV valves are shut

4. Semilunar valves are forced open

In systoli, describe the activity of the: 1. atria 2. ventricles 3. AV valves 4. semilunar valves

- Sinoatrial (SA) node

- Base of SVC

Name the local electrical supply of the atria

- Atrioventricular (AV) node

- interatrial septum above tricuspid valve

- leads to AV bundle (aka bundle of His) and then branches

Describe the local nervous supply of the ventricles

ant: sternal angle (aka manubrio-sternal joint)

post: intervertebral disc between T4+T5

Name the anterior and posterior border of the Plane of Louis

1. Oesophagus

2. Trachea

3. Vagus N.

4. Brachiocephalic trunk (aka artery)

5. Right brachiocephalic vein

6. Left brachiocephalic vein

7. Superior Vena Cava (SVC)

Fill the blanks

- Thymus

- Brachiocephalic veins (r+l)

- SVC

- Arch of Aorta: Brachiocephalic artery, left common carotid, left subclavian

- Internal thoracic vessels

- Phrenic + vagus N.

- Cardiac plexus of nerves

- Recurrent laryngeal nerves

- Trachea

- Oesophagus

- Thoracic duct (lymph)

Main contents of the superior mediastinum

- Loose CT

- Fat

- Thymus

- Lymphatics

- Sterno-pericardial ligaments

- Internal thoracic vessels

What are the main contents of the anterior mediastinum?

- Phrenic nerves

- pericardium

- heart

- cardiac plexus

- ascending aorta

- SVC

- IVC

- pulmonary trunk

- pulmonary veins

What are the main contents of the middle mediastinum?

- thoracic duct (main lymph vessel)

- azygous system of veins

- descending aorta

- oesophagus

- oesophageal plexus

- sympathetic trunk

What are the main contents of the posterior mediastinum?

Passage of thoracic duct from right to left behind oesophagus

Angle of Louis

Tracheal bifurcation

End of azygous veins into SVC

Ligamentum arteriosum

Loop of left recurrent laryngeal nerve around aortic arch

Aortic arch starts and ends

List the main features or occurrences of the plane of louis (PATELLA)

1. Azygous vein

2. Bronchus

3. Oesophagus

4. Oesophageal plexus

5. SVC

6. Right phrenic nerve

Fill the blanks

1. Left coronary artery

2. circumflex artery (branch)

3. Left anterior descending (aka left anterior intraventricular) artery

Fill the blanks

1. right coronary artery

2. posterior intraventricular artery

3. right marginal artery

1. middle cardiac vein

2. great cardiac vein

3. small cardiac vein

Right atrium

where does the coronary sinus drain into_

- from vagus nerve

What supplies the parasympathetic input of the heart?

- T1-T5 via sympathetic chain

What supplies the sympathetic input of the heart?

- brachiocephalic node

- tracheobronchial node

To which nodes does lymph of the heart drain?

left brachiocephalic vein

To which vein does the lymph of the heart drain?

The atria are thinner than the ventricles and the left ventricle is thicker than the right

comment on the thickness of atrial and ventricular muscle

- tunica externa/adventitia: connective tissue + elastic fibres. Blends with tissue and stabilises

- tunica media: smooth muscles + elastic fibres

- tunica intima: connective tissue+ single cell layer endothelium (SSE tissue)

Describe the 3 layers of the blood vessels