Blood Pressure • Blood pressure (BP) is the pressure or tension exerted on the arterial walls as blood pulsates through them (principal vital sign) • Systolic blood pressure (SBP) – pressure exerted on the arteries during the contraction phase of the heartbeat. • Diastolic blood pressure (DBP) – the resting pressure on the arteries as the heart relaxes between contractions.
Diastolic phase: heart relaxes, BP falls, heart fills with blood Systolic phase : heart contracts, BP rises, heart pumps blood out to the body
The average BP, due to the pumping by the heart and resistance in blood vessels decreases as the circulating blood moves away from the heart through the body. Gravity, valves in veins and pumping from contracting of skeletal muscles are some other influences on BP at various places in the body.
Reporting BP Unit of measurement: Millimeters of mercury (mmHg) “LUB” 120 80 “DUB”
Blood Pressure (cont.) • Classification of BP for Adults
Blood Pressure (cont.) • Sites for Blood Pressure Assessment • Brachial artery – taken on the upper arm; most common site. • Radial artery – taken on the lower arm; possible site for infants or clients who have very large upper arms. • Popliteal artery– taken on the thigh. • Dorsalis pedis and posterior tibial – taken on the lower leg.
Blood Pressure (cont.) • Equipment for Measuring Blood Pressure • Blood pressure is measured using a sphygmomanometer, also called a BP cuff, or cuff. Sounds like: SFIG-moh-mə-NOM-i-ter
Blood Pressure (cont.) • Equipment for Measuring Blood Pressure Types of Sphygmomanometers • Mercury– has a calibrated glass tube containing mercury. • Aneroid– has a calibrated dial with a needle that points to numbers on the face of the dial. • Electronic– uses a digital display and usually includes the pulse rate. Mercury Aneroid Digital
Homework:What factors affect HR & BP? Heart Rate Blood Pressure
Scientific Investigation Inquiry Question: Variables: • Independent Variable: What will be manipulated? • Dependent Variable: What will be affected? • Control: What will we compare our results to? OR What will remain constant?