Cardiovascular System

• When the heart stops beating, the body's unique structure in space changes.
• Blood transports gases, nutrients and waste products such as oxygen.
• Blood transports processed molecules like precursor of vitamin D from skin to liver then kidneys.
• Blood transports regulatory molecules like hormones.
• Blood regulates pH and osmosis, maintaining most body tissues between 7.35 and 7.45.
• Atherosclerosis is the deposition of plaque on walls.
• Elastic or conducting arteries have a relatively thick tunica intima and a thin tunica media.
• Arteriosclerosis is a general term for degeneration changes in arteries that make them less elastic.
• Elastic or conducting arteries have the largest diameters, experience high pressure that fluctuates between systolic and diastolic, and contain more elastic tissue than muscle.
• Blood maintains body temperature by shunting warm blood to the interior of the body.
• Blood protects against foreign substances like antibodies.
• Blood clots when necessary.
• The composition of blood includes a liquid part called plasma, which is 91% water, and a solid part called blood cells, which include red blood cells, white blood cells, and platelets.
• Red blood cells are biconcave discs, anucleate, contain hemoglobin, and transport oxygen and carbon dioxide.
• White blood cells can be granulocytes with large granules and multi-lobed nuclei, or agranulocytes with small granules and nuclei that are not lobed.
• Granulocytes include neutrophils, eosinophils, and basophils, while agranulocytes include lymphocytes and monocytes.
• Platelets are cell fragments that form platelet plugs and release chemicals necessary for blood clotting.
• Blood Chemistry is the composition of materials dissolved or suspended in the plasma, used to assess the functioning of many body systems.
• The Heart generates blood pressure, routes blood, ensures one-way blood flow, and regulates blood supply.
• Complete Blood Count includes the number of Red Blood Cells per microliter of blood and the amount of Hemoglobin per 100 mL of blood.
• The Heart is the size of a closed fist, has a shape like a cone with a blunt rounded point at the apex and a flat part at the base, and is located in the thoracic cavity in the mediastinum.
• The Heart has an anatomy that includes the Pericardium or pericardial sac, which consists of the fibrous pericardium, a tough fibrous outer layer that prevents over distention and acts as an anchor, the serous pericardium, a thin, transparent, inner layer, and the parietal pericardium, which lines the fibrous outer layer.
• The Heart has an external anatomy that includes the Coronary Arteries, which include the Right Coronary Artery, which exits the aorta just superior to the point where the aorta exits the heart and is smaller than the Left, and the Left Coronary Artery, which exits the aorta near the Right Coronary Artery.
• White Blood Cell Count is 5,000-10,000 White Blood Cells per microliter of blood.
• Clotting includes Platelet Count (250,000- 400,000/microliter) and Prothrombin Time Measurement, which measures how long it takes for blood to start clotting.
• Red blood cells are tested against antibodies.
• Differential White Blood Count determines the percentage of each of the five types of White Blood Cells: Neutrophils (60-70%), Lymphocytes (20-30%), Monocytes (2-8%), Eosinophils (1-4%), and Basophils (0.5-1%).
• Hematocrit Measurement is the percent of blood that is Red Blood Cells.
• Specialized cardiac muscle cells generate spontaneous action potentials.
• Capillaries consist of endothelial cells, basement membrane, and a delicate layer of loose connective tissue, and scattered pericapillary cells are fibroblasts, macrophages or undifferentiated smooth muscle cells.
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• Capillaries can be continuous with no gaps between endothelial cells and no fenestrae, or fenestrated with pores and numerous fenestrae, or sinusoidal with large fenestrae and less basement membrane.
• Arteries and veins consist of the tunica intima (endothelium, basement membrane, lamina propria, internal elastic membrane), tunica media (smooth muscle cells arranged circularly around the blood vessel), and tunica externa (adventitia) (connective tissue, varies from dense regular near the vessel to loose that merges with the surrounding connective tissue).
• Purkinje fibers are large diameter cardiac muscle cells with few myofibrils and many gap junctions.
• The functions of the circulatory system include carrying blood, exchanging nutrients, waste products, and gases, transporting hormones, components of the immune system, molecules required for coagulation, enzymes, nutrients, gases, waste products, etc., regulating blood pressure, and directing blood flow.
• Arteries can be elastic, muscular, or arterioles, and capillaries are the site of exchange with tissues.
• Right and left bundle branches extend beneath the endocardium to the apices of right and left ventricles.
• Action potentials pass to atrial muscle cells and to the AV node.
• Substances move through capillaries by diffusion through the plasma membrane.
• The AV bundle, which passes through a hole in the cardiac skeleton to reach the interventricular septum, is part of the conduction system.