HEART PHYSIOLOGYHow 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