Circulatory Circulatory System

Function: Pickup & delivery system Pick up wastes (carbon dioxide) from cells; deliver nutrients (oxygen) to cells

Components: Heart (fist-sized pump) Blood Vessels

Cardio- = heart Cardiologist = heart specialist

Heart Structure:

Four Chambers: Atria = 2 upper chambers Ventricles = 2 lower chambers Valves = flaps that keep blood flowing in 1 direction Semilunar valves = lead out of heart Septum = wall that separates 2 sides of heart

Heart Sounds: “Lub dup” – sound of valves closing Initial sound = closing of bicuspid & tricuspid valves Second sound = semilunar valves closing

Heart Sounds: Murmur = blood flowing backward through heart when valves don’t close tightly

Blood Vessels: Arteries (carry blood away from heart) Veins (carry blood to heart) Capillaries (tiniest blood vessels/where diffusion occurs)

Arteries Aorta = largest artery Carry blood away from heart Carry blood under high pressure Round in shape w/ thick muscular walls – buried deep w/in body

Veins Vena Cava = largest vein Carry blood to heart Carry blood under low pressure Flat in shape & have little muscle Many 1-way valves to keep blood flowing in 1 direction – toward heart

Veins Continued: Varicose Veins = faulty valves in leg veins – blood pools in veins, causing them to bulge. “spider veins”

Capillaries: Smallest blood vessels – connect arteries to veins 1 cell thick Pickup & delivery (diffusion) occurs here

Right Side Deoxygenated blood (pumps blood to lungs)

Left Side Oxygenated blood (pumps blood to body cells)

Pulse Pulse = heart rate Avg. = beats/min. Taken at radial (wrist) or carotid (neck) artery

Blood Pressure (BP) Force that blood exerts on the walls of an artery Systolic pressure/diastolic pressure Ventricles contracting/ventricles relaxing /65-90 mm Hg = normal 120/80 mm Hg = average

BP Increases gradually as we age Sphygmomanometer = cuff, bulb, gauge Stethoscope = used to transmit & amplify bodily sounds

Hypotension vs. Hypertension Hypertension = high BP (hyper- = over, above) “Silent killer” Arteries too narrow for easy blood flow, damages organs Control: low salt diet, exercise (weight loss), meds.

Hypertension vs. Hypotension Hypotension = low BP (hypo- = low)

Pacemaker Specialized cardiac muscle cells buried deep within wall of right atrium Generate electrical impulse and cause heart to contract Defective? Heart will beat irregularly or stop altogether unless you receive an electronic pacemaker

Circulatory Disorders/Treatments: Arterioschlerosis = aging process that stiffens artery walls Atheroschlerosis = cholesterol deposits build up on artery walls, narrowing them Both terms referred to as “hardening of the arteries” Angina = chest pains Coronary arteries = supply heart w/ oxygen

Circulatory Disorders/Treatments: Heart attack = death of part of heart muscle due to lack of oxygen “myocardial infarction” Fibrillation = very fast and irregular heart rate Defibrillation = applying electrical shock to heart to restore normal rhythym

Circulatory Disorders/Treatments: Angioplasty = “balloon surgery” Inserting deflated balloon into blocked vessel & inflating it to push cholesterol deposits against artery walls – not a cure – must be repeated

Circulatory Disorders/Treatments: Bypass surgery = detour Another vessel (usually a leg vein) is sewn in above & below point of blockage Sketch on whiteboard Double, triple, quadruple

Circulatory Disorders/Treatments: Stroke = blood clot to brain Blood clot = tangled mesh of blood cells Thrombus = blood clot Embolus = traveling blood clot

Circulatory Disorders/Treatments: Heart transplant = possibility of rejection Artificial heart = plastic/metal pump; advantages: always available, not rejected by body; disadvantages: large power source must be carried outside body Artificial heart is used to keep person alive until donor heart becomes available.