pmls 2

• The heart circulates blood throughout the body and is located in the center of the thoracic cavity
• The heart is a four-chambered, hollow, muscular organ surrounded by a sac called Pericardium
• Coronary circulation is the flow of blood within the heart muscle, receiving oxygen via left & right coronary arteries
• Angina is chest pain due to reduced blood flow to the heart muscle, caused by narrowing, obstruction, or spasm of the coronary arteries
• Atherosclerosis is the buildup of plaque leading to severe narrowing of coronary arteries and reduced blood flow to the heart muscle
• A heart attack is caused by a partial obstruction of a coronary artery, resulting in "myocardial ischemia" or "myocardial infarction" with complete obstruction
• The heart's contractions are synchronized by means of specialized muscle cells, initiated by an electrical impulse from the "sinoatrial node (SA)" or pacemaker
• An electrocardiogram (ECG/EKG) is a graphic record of the heart's electrical activity, with waves representing different activities of the heart
• Heart rate is the number of heartbeats per minute, with an average of 72 bpm for adults
• Cardiac output is the volume of blood pumped by the heart in one minute, averaging 5L/min
• Blood pressure is the force exerted by blood on the walls of blood vessels, expressed as systolic (during ventricular contraction) and diastolic (during ventricular relaxation) pressure
• Arteries flow blood away from the heart, veins return blood to the heart, and capillaries connect most arteries and veins allowing for exchange of gases and nutrients
• Arteries have thick walls to withstand pumping pressure and carry oxygenated blood, while veins have thinner walls, valves to prevent backflow, and carry deoxygenated blood
• Capillaries connect arterioles and venules, allowing the exchange of oxygen for carbon dioxide and nutrients for waste
• Blood vessels have layers including Tunica Adventitia (outer layer), Tunica Media (middle layer), and Tunica Intima (inner layer)
• The antecubital fossa is the first choice for venipuncture due to its accessibility and large veins, with variations like H-Pattern and M-Pattern Antecubital Veins
• In the H-Pattern Antecubital Veins, the median cubital vein is the first choice for venipuncture, followed by the cephalic vein and basilic vein
• In the M-Pattern Antecubital Veins, the veins follow a different pattern and have specific characteristics for venipuncture
• The basilic vein for venipuncture is difficult to palpitate, has a tendency to roll, and is near the brachial artery and median cutaneous nerve, making it more painful
• The circulatory system is the transportation system for the body to transfer substances, with the pulmonary system circulating blood through the lungs and the systemic system supplying cells with needed nutrients and removing waste products
• Blood volume varies based on the individual's size, with only 2.5% of an individual's blood able to be taken at once and no more than 5% of the total patient's blood in 30 days
• Hematopoiesis is the continuous, regulated process of renewal, proliferation, differentiation, and maturation of all blood cell lines, resulting in the release of blood cells from bone marrow into circulation
• Serum appears as a clear, pale-yellow fluid used for many laboratory tests, while plasma is the liquid portion of blood inside the body and contains fibrinogen and clotting factors
• Blood elements consist of a liquid portion (plasma/serum) making up 55% and cellular elements making up 45%, including erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets)
• Red blood cells are biconcave in shape, lack a nucleus, have a viability of 120 days, and contain hemoglobin which carries oxygen and determines blood type
• Leukocytes are produced in the bone marrow and lymph nodes, vary greatly in size, and have staining characteristics for differentiation
• Thrombocytes are the smallest of the formed elements, fragments of megakaryocytes, and aid in the clotting process
• Centrifugation spins blood in an upright position to separate components by weight, with heavier cellular components settling at the bottom
• Coagulation is the conversion of liquid blood into a semisolid gel called a "clot," critical for hemostasis to stop bleeding, involving activation of coagulation factors and prevented by anticoagulants in blood tubes
• Primary hemostasis involves vasoconstriction, platelet aggregation, and platelet adhesion, while secondary hemostasis is needed for more serious injuries and involves the formation of a fibrin clot through a coagulation cascade