cardiovascular system

• The cardiovascular system is a closed system of the heart and blood vessels that functions to circulate oxygen, provide cells with nutrients, transport oxygen, nutrients, cell wastes, hormones to and from cells, remove waste products of metabolism to excretory organs, and help regulate body temperature.
• The functional components of the cardiovascular system include the heart, blood vessels, and blood.
• The heart, approximately the same size as a closed fist, rests at the diaphragm and is located in the mediastinum.
• Atria contract, forcing additional blood into ventricles.
• AV valves open; atrial pressure greater than ventricular pressure.
• Ventricles contract, forcing blood against AV valve cusps.
• AV valves close.
• Ventricles AV valves closed; atrial pressure less than ventricular pressure.
• Pulmonary trunk As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open.
• Blood returning to the atria puts pressure against AV valves, forcing them open.
• As the ventricles fill, AV valve cusps hang limply into ventricles.
• Chordae tendineae tighten, preventing valve cusps from everting into atria.
• The apex of the heart is directed toward the left hip and rests on the diaphragm, while the base points toward the right shoulder.
• The location of the heart within the thorax can be seen in Figure 11.1a.
• The heart wall and coverings include the pericardium, which is composed of the fibrous pericardium and the serous pericardium.
• The pressure read as the first soft tapping sounds are heard is recorded as the systolic blood pressure.
• The brachial artery is closed when measuring blood pressure.
• The pressure in the cuff is gradually reduced while the examiner listens (auscultates) for sounds in the brachial artery with a stethoscope.
• A rubber cuff inflated with air is used to measure blood pressure.
• Pressure in cuff above 120 results in no sounds audible.
• The pressure at which the sounds disappear is recorded as the diastolic blood pressure.
• The blood pressure cuff is wrapped snugly around the arm just above the elbow and inflated until the cuff pressure exceeds the systolic blood pressure.
• At the point where blood flow into the arm is stopped, a brachial pulse cannot be felt.
• As the pressure is reduced still further, the sounds become louder and more distinct; when the artery is no longer constricted and blood flows freely, the sounds can no longer be heard.
• Ventricular diastole, also known as atrial diastole, is the phase of the heart cycle where the left ventricle fills with blood.
• Isovolumetric contraction is a phase of the heart cycle where the ventricles contract with no change in ventricular volume.
• Electrocardiogram consists of elements such as waves and segments.
• Ventricular systole, also known as atrial systole, is the phase of the heart cycle where the left ventricle contracts and ejects blood.
• Atrial diastole, also known as ventricular filling, is the phase of the heart cycle where the left ventricle fills with blood.
• Atrial systole, also known as ventricular systole, is the phase of the heart cycle where the left ventricle contracts and ejects blood.
• Electrocardiogram, also known as ECG or EKG, is the recording of the electrical activity of the heart based on recording of electric potentials generated by the heart.
• Isovolumetric relaxation is a phase of the heart cycle where the ventricles relax with no change in ventricular volume.
• The left atrium and right atrium are chambers in the heart that receive blood.
• The pericardium consists of the fibrous pericardium, which is loose and superficial, and the serous pericardium, which is deep to the fibrous pericardium and composed of two layers: the parietal pericardium, which lines the inner surface of the fibrous pericardium, and the visceral pericardium, which is next to the heart, also known as the epicardium.
• Serous fluid fills the space between the layers of pericardium, called the pericardial cavity.
• Mean Arterial Pressure (MAP) is calculated as DBP + 1/3 PP.
• Two arterial blood pressures are measured in measuring blood pressure: systolic — pressure in the arteries at the peak of ventricular contraction, and diastolic — pressure when ventricles relax.
• Vascular resistance is the opposition to blood flow due to friction between blood and walls of blood vessels, with factors including the size of the lumen and blood viscosity.
• Pulse is monitored at pressure points in superficial arteries, where it is easily palpated.
• Factors affecting blood flow include blood pressure, vascular resistance, and venous return.