undefined
Circulatory System
Review
Your turn!
Other information about the Heart
Electrical impulses cause contraction of the heart muscle
Atrioventricular node (AV): Group of nerve cells located between atria and ventricles. Sends the electrical impulse through the,,,,,,
Bundle of HIS: Nerve fibers in the septum; divided into right and left bundle branches. Carry the impulse through the ventricles to the......
Purkinje Fibers: Network of nerve fibers throughout the ventricles. Electrical impulse reaches all the muscle tissue in the ventricles and they contract.
This electrical impulse occurs about every 0.8 seconds.
Blood Cells
Leukocytes (White Blood Cells): Formed in bone marrow and lymph tissue. Life cycle about 3 - 5 days. About 5,000 - 10,000/ cubic mm. Pass through capillary walls and enter body tissues. Fight infection.
Five types of Leukocytes
Neutrophils: phagocytize bacteria by secreting lysozyme
Eosinophils: remove toxins, defend body from allergic reactions by producing antihistamines
Basophils: Body's inflammation response; produce histamine and heparin
Monocytes: phagocytize bacteria and foreign materials
Lymphocytes: immunity for the body, develops antibodies; protect against formation of cancer cells.
Thrombocytes: Platelets; fragments of cells, no nucleus, vary in shape and size. Formed in the bone marrow; live 5 to 9 days. Normal count 250,000 - 400,000/cubic mm
Important to clotting process to stop the bleeding.
Diseases and Abnormal Conditions
Aneurysm: ballooning out or saclike formation on artery wall. If it ruptures, hemorrhage occurs, can cause death
Arteriosclerosis: hardening or thickening of arterial walls; loss of elasticity and contractiity. HBP, aneurysm, or cerebral hemorrhage.
Atherosclerosis: fatty plaque (cholesterol) deposited on walls of arteries. Narrows arterial opening, restricts blood flow. If plaques breaks off wall can become an emboli.
CHF: heart muscles do not beat adequately to supply blood supply to the body. Right or left side. Edema, dypsnea, pallor, cyanosis, distention of neck veins, weak rapid pulse, cough
Embolus: foreign substance in blood stream - air, blood clot, bacterial clumps, fat globule,
Hemophilia: inherited almost only in males but carried by females. Lack plasma protein for clotting.
Hypertension: HBP - above 140/ 90; family history, race, obesity, stress, smoking, aging and diet.
Leukemia: malignant disease of bone marrow or lymph tissue. High number of immature white blood cells. Fever,pallor, swelling of lymphoid tissues, fatigue, anemia, bleeding gums, excessive bruising, and joint pain.
Myocardial nfarction (heart attack): blockage of coronary arteries cuts off supply of blood to heart. Severe crushing pain to arm, neck and/ or jaw. Pressure in chest. Perspiration and cold, clammy skin; dypsnea; change in blood pressure.
Phlebitis: Inflammation of a vein; frequently in the leg.
thrombus forms - thrombophlebitis. Pain, edema, redness and discoloration at the site
Varicose veins: Dilated, swollen veins. Elasticity lost causing stasis or decreased blood flow.