Circulation Chapter 14

Cardiovascular Disease Risk Factors

• Physical inactivity is a risk factor for cardiovascular disease

Mississippi Health Statistics

• In 2021, Mississippi had the highest state rank for physical inactivity
• In 2021, 47.7% of adults in Mississippi reported being physically inactive
• In 2021, 7.3% of women in Mississippi reported being told by a health professional that they have heart disease

Women's Health

• Heart disease is the leading cause of death in women
• Approximately 3.5 million women in the US are living with breast cancer

Cardiovascular Disease and Age

• Older adults may have a higher risk of cardiovascular disease
• Every day, approximately 10,000 people turn 65

Overall Health

• Regular physical activity is an important part of overall health

Diabetes in Mississippi

• In 2021, Mississippi ranked 4th in the state rank for adult diabetes

American Heart Association Recommendations

• The American Heart Association recommends regular physical activity, a healthy diet, and maintaining a healthy weight for people with heart disease

Circulatory System

• The main function of the circulatory system is to transport oxygen and nutrients to tissues and organs
• Blood flow through a vessel is calculated by the equation Q = ΔP / R, where Q is flow, ΔP is pressure difference, and R is resistance

Blood Flow

• The relationship between pressure, flow, and resistance is: flow is directly proportional to pressure difference and inversely proportional to resistance
• Laminar flow occurs when blood flows at a steady rate and each layer of blood remains the same distance from the vessel wall
• The equation for cardiac output is CO = HR x SV, where CO is cardiac output, HR is heart rate, and SV is stroke volume

Vascular Tree

• Arterioles have the thickest muscular wall and control blood flow
• Capillaries have the thinnest wall and are responsible for nutrient exchange
• The pressure is lowest in the venous system
• The venous system is considered to have high compliance due to its ability to expand and store blood

Resistance to Blood Flow

• The resistance of the entire circulatory system is called total peripheral resistance
• The Reynold's number is a measure of the tendency for turbulence to occur in blood flow
• The factor that has the most significant impact on resistance to blood flow is vessel diameter
• According to Poiseuille's Law, the equation for blood flow is Q = (π × r^4 × ΔP) / (8 × η × L), where Q is flow, r is vessel radius, ΔP is pressure difference, η is viscosity, and L is vessel length
• In a parallel circuit, total resistance is calculated by 1/Rt = 1/R1 + 1/R2 + ... + 1/Rn

Hematocrit and Viscosity

• The relationship between hematocrit and viscosity is: viscosity increases as hematocrit increases
• The normal hematocrit range for females is 37-48%

Anemia and Antibiotic Prophylaxis

• The purpose of antibiotic prophylaxis before invasive dental procedures in individuals with anemia is to prevent bacterial endocarditis

Blood Flow Measurement

• The electromagnetic flowmeter measures blood flow by utilizing the generation of electromotive force in blood moving through a magnetic field