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The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
The back surface of the heart lies near the vertebral column, and the front surface known as the sternocostal surface sits behind the sternum and rib cartilages. [8] The upper part of the heart is the attachment point for several large blood vessels—the venae cavae, aorta and pulmonary trunk.
The mediastinum (from Medieval Latin: mediastinus, lit. 'midway'; [2] pl.: mediastina) is the central compartment of the thoracic cavity.Surrounded by loose connective tissue, it is a region that contains vital organs and structures within the thorax, namely the heart and its vessels, the esophagus, the trachea, the vagus, phrenic and cardiac nerves, the thoracic duct, the thymus and the lymph ...
The list below describes such skeletal movements as normally are possible in particular joints of the human body. Other animals have different degrees of movement at their respective joints; this is because of differences in positions of muscles and because structures peculiar to the bodies of humans and other species block motions unsuited to ...
Early inductive effects of the axial mesoderm upon the overlying neural ectoderm is the mechanism that establishes the length dimension upon the brain primordium, jointly with establishing what is ventral in the brain (close to the axial mesoderm) in contrast with what is dorsal (distant from the axial mesoderm). Apart from the lack of a causal ...
A slow heart rate of 60 or less beats per minute is defined as bradycardia. A fast heart rate of more than 100 beats per minute is defined as tachycardia. An arrhythmia is defined as one that is not physiological such as the lowered heart rate that a trained athlete may naturally have developed; the resting heart rates may be less than 60 bpm.
It separates the heart from interference of other structures, protects it against infection and blunt trauma, and lubricates the heart's movements. The English name originates from the Ancient Greek prefix peri- (περί) 'around' and the suffix -cardion (κάρδιον) 'heart'.
The developing heart at day 30. The septum primum (top, middle) develops downwards to separate the initially joined primitive atrium into left and right atria. At the end of the fourth week, a crest grows that leaves the cephalic part. This crest is the first part of the septum primum.