CHAPTER 27 Summary

• The cardiovascular system transports nutrients, oxygen, hormones, and other substances throughout the body. It consists of the heart, blood vessels, and blood.
• The heart acts as a pump, moving blood in two circuits between the heart and lungs (pulmonary circuit) and between the heart and the rest of the body (systemic circuit).
• Different types of blood vessel have different structures and functions. Arteries transport blood away from the heart, veins transport blood to the heart, and capillaries are the sites of nutrient and gas exchange in tissues.
• Blood is composed of cells and fluid. Red blood cells (erythrocytes) are the oxygen-carrying cells.
• Atherosclerosis, or hardening of the arteries, is a common form of cardiovascular disease, which can lead to heart attack.
• A heart attack results when the blood supply to the heart muscle is cut off and the muscle begins to die; atherosclerosis in coronary arteries is a common cause of a heart attack.
• High blood pressure (hypertension), obesity, high cholesterol, and smoking are known risk factors for atherosclerosis.
• Blood pressure is expressed as systolic pressure/diastolic pressure. Normal blood pressure is ~120/80.
• Hypertension is a dangerous condition if left untreated. There are both controllable and uncontrollable causes of hypertension.
• Cholesterol is a normal constituent of cells, but too much LDL cholesterol in the blood can contribute to cardiovascular disease through the accumulation of plaque in arteries. Eating saturated fats elevates LDL levels.
• Cardiovascular disease begins early in life, long before symptoms occur. Autopsy studies have documented that atherosclerosis occurs in the arteries of young people and correlates with risk factors during life.

• MORE TO EXPLORE

  • American Heart Association http://www.heart.org
  • Centers for Disease Control and Prevention: Heart Disease http://www.cdc.gov/heartdisease
  • Berenson, G. S., et al., for the Bogalusa Heart Study. (1998) Association between multiple cardiovascular risk factors and atherosclerosis in children and young adults. New England Journal of Medicine 338:1650–1656.
  • Broyles, S., et al. (2010) The pediatric obesity epidemic continues unabated in Bogalusa, Louisiana. Pediatrics 125:900–905.
  • May, A. L., et al. (2012) Prevalence of cardiovascular disease risk factors among US adolescents, 1999–2008. Pediatrics 129:1035–1041.
  • HBO. (2012) Weight of the Nation.