The Heart
⚫ The heart is a hollow muscular organ located in the
chest cavity, the inferior(middle) mediastinum within
the pericardial sac. It rests on the central tendon of
the diaphragm and is flanked on either side by the
right and left pulmonary cavities.
⚫ Mediastinum is the space between the medial part of
the lungs.
⚫ 2/3 of the heart is located left to the midline and 1/3
is located right to the midline.
⚫ The heart has a conical shape. The base
(superiorily), anchored by the great vessels, is
on its superior and posterior surfaces. The apex,
located approximately at the 5th intercostal
space lateral and left to midclavicular line,
projects anteriorly, inferiorly, and to the left and
moves freely within the pericardial sac. The heart is
covered by the pericardial membrane.
,⚫ The cardiovascular system connsists of: heart
(cenrtral organs) and 2 circulations: systemic and
pulmonary.
⚫ The heart acts as a pump for both circulations.
⚫ The 2 circulations start from the ventricles and
end in the atrium.
⚫ Types of blood vessels:
1. Arteries: carrying blood from heart to the
peripheral organs. (Oxygenated/deoxygenated).
2. Veins: carrying blood from the peripheral lungs to
the heart.
3. Blood capillaries.
,The Pericardium and Pericardial Cavity
⚫ The pericardium, a double fibroserous membrane, forms the
pericardial sac that surrounds the heart and the origins of the great
vessels.
⚫ The pericardium is composed of two layers: an outer fibrous layer and
an inner serous layer.
◦ 1. The outer fibrous pericardium is composed of tough in-elastic connective
tissue. It is attached inferiorly to the diaphragm and is continuous superiorly
with the tunica adventitia (outer layer) of the great vessels.
◦ 2. The thin serous pericardium consists of a parietal part and a visceral part.
● The parietal layer (part) of serous pericardium lines the inner surface of the parietal
pericardium.
● The visceral layer (part) of serous pericardium firmly adheres to the outer surface of
the heart as the epicardium. This layer is continuous with the parietal layer of the
serous pericardium at the root of the great vessels.
⚫ Pericardiacophrenic arteries, branches of the internal thoracic
arteries, provide the main blood supply to the pericardium. Veins that
accompany the arteries drain into the superior vena cava.
⚫ The vagus (CN X) and phrenic nerves (C3–C5) and branches from the
sympathetic trunks innervate the pericardium.
⚫ Pericardial pain is often referred via the phrenic nerve to the skin of the
ipsilateral supraclavicular region (dermatomes C3–C5).
, The fibrous pericardium.
⚫ The heart is a hollow muscular organ located in the
chest cavity, the inferior(middle) mediastinum within
the pericardial sac. It rests on the central tendon of
the diaphragm and is flanked on either side by the
right and left pulmonary cavities.
⚫ Mediastinum is the space between the medial part of
the lungs.
⚫ 2/3 of the heart is located left to the midline and 1/3
is located right to the midline.
⚫ The heart has a conical shape. The base
(superiorily), anchored by the great vessels, is
on its superior and posterior surfaces. The apex,
located approximately at the 5th intercostal
space lateral and left to midclavicular line,
projects anteriorly, inferiorly, and to the left and
moves freely within the pericardial sac. The heart is
covered by the pericardial membrane.
,⚫ The cardiovascular system connsists of: heart
(cenrtral organs) and 2 circulations: systemic and
pulmonary.
⚫ The heart acts as a pump for both circulations.
⚫ The 2 circulations start from the ventricles and
end in the atrium.
⚫ Types of blood vessels:
1. Arteries: carrying blood from heart to the
peripheral organs. (Oxygenated/deoxygenated).
2. Veins: carrying blood from the peripheral lungs to
the heart.
3. Blood capillaries.
,The Pericardium and Pericardial Cavity
⚫ The pericardium, a double fibroserous membrane, forms the
pericardial sac that surrounds the heart and the origins of the great
vessels.
⚫ The pericardium is composed of two layers: an outer fibrous layer and
an inner serous layer.
◦ 1. The outer fibrous pericardium is composed of tough in-elastic connective
tissue. It is attached inferiorly to the diaphragm and is continuous superiorly
with the tunica adventitia (outer layer) of the great vessels.
◦ 2. The thin serous pericardium consists of a parietal part and a visceral part.
● The parietal layer (part) of serous pericardium lines the inner surface of the parietal
pericardium.
● The visceral layer (part) of serous pericardium firmly adheres to the outer surface of
the heart as the epicardium. This layer is continuous with the parietal layer of the
serous pericardium at the root of the great vessels.
⚫ Pericardiacophrenic arteries, branches of the internal thoracic
arteries, provide the main blood supply to the pericardium. Veins that
accompany the arteries drain into the superior vena cava.
⚫ The vagus (CN X) and phrenic nerves (C3–C5) and branches from the
sympathetic trunks innervate the pericardium.
⚫ Pericardial pain is often referred via the phrenic nerve to the skin of the
ipsilateral supraclavicular region (dermatomes C3–C5).
, The fibrous pericardium.
