Heart Anatomy, Valves and Circulation of Blood

What is pericardium?

Outer membrane surrounding & protecting the heart

Function of pericardium?

Confined heart to position in mediastinum, whilst allowing enough freedom of movement for contraction.

2 main layers of pericardium

• fibrous

• serous

Layers of serous pericardium?

Visceral and parietal pericardium

Role of fibrous pericardium?

• Prevent overstretching of the heart

• Provides protection

• Anchors heart in the mediastinum

Where is pericardial fluid located - what is its role?

Located in-between parietal and visceral pericardium

• lubricates = reducing friction and heart moves

What cells produce pericardial fluid?

pericardial cells

Inflammation of the pericardium?

pericarditis

3 layers of heart wall

From external to internal:

• Epicardium

• Myocardium

• Endocardium

Describe epicardium

Serous layer of pericardium - houses coronary arteries and cardiac vessels supplying myocardium

Describe myocardium

Cardiac muscle - composed of endomysium and perimysium

Describe endocardium

Thin layer of endothelium forming smooth lining of heart chambers

• reducing friction of blood on heart surface

• continuous with lining of blood vessels

What do valves open and close to?

Pressure changes as heart contracts

When do the papillary muscles of the AV valves contract?

When the ventricles contract.

• pressure of blood drives cusps upwards until edges meet

• papillary muscles contract, tightening the chordae tendineae & preventing the valves from everting

what prevents backflow of blood through SL valves?

Backflowing blood fills valve cusps - free edges of SL valves contact each other tightly and close

Which vessels are the only ones to fill during diastole?

Coronary arteries

How do the coronary arteries fill with blood during diastole?

The position of coronary arteries causes the backflow of blood due to the elastic recoil of elastic aorta.

• blood flows into the aortic sinuses and coronary arteries