HEART PHYSIOLOGY How the heart works.

HEART SOUNDS

Blood turbulence from closing valves 2 sounds: lubb (closing of valves between atria and ventricles) Dupp (closing of valves after ventricles)

ELECTROCARDIOGRAM (ECG or EKG)

Recorded electrical currents of heart Determine healthy heart

FACTORS AFFECTING BLOOD FLOW

Vol. of blood through any tissue for a given time period. Factors: Cardiac output: heart rate x stroke volume Blood pressure Blood volume Resistance Size of vessel diameter Blood viscosity Total blood vessel length

HYPERTENSION

High blood pressure Major cause of heart failure and stroke Causes: Overweight Excessive alcohol Lack of exercise Diet: high salt, low minerals (K, Ca) stress

BLOOD FLOW

pulse Alternating expansion and recoil of an artery Wrist pulse = radial artery Neck pulse = carotid artery

Blood pressure Generated by contraction of ventricles Pressure exerted by blood on walls of a blood vessel Highest in aorta; falls as distance from left ventricle increases Bp, as a vital sign, measures pressure in aorta/large arteries

Blood pressure 2 measurements: systolic (heart contraction) and diastolic (relaxation) pressure. EX. 120/80 Affected by cardiac output and peripheral resistance