BISC276 Lecture Notes - Lecture 20: Rheumatic Fever, Yolk Sac, Desmosome
20 Dec 2016
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Document Summary
Between the lungs in the mediastinum with about two-thirds of its mass to the left of the midline. Pericardial cavity: between the parietal and visceral layers of the serous pericardium. Pericardial fluid: fills the potential space and reduces friction between the two membranes: pericarditis: inflammation of the pericardium. Heart chambers: 2 upper atria and 2 lower ventricles. The thickness of the myocardium of the four chambers varies according to the function of each chamber. Valves open and close in response to pressure changes as the heart contracts and relaxes: atrioventricular (av) valves. Allow movement of blood from atria ventricles . Prevent blood flow from the ventricles back into the atria. Back flow is prevented by the contraction of papillary muscles tightening the chordae tendinae which prevent the valve cusps from everting: semilunar (sl) valves. Three crescent cusps without chordae tendinae each. Allow ejection of blood from the ventricles arteries. Prevent back flow of blood into the ventricles.
