Transcript Circulatory System

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
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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
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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. = 60-80 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
• 110-140/65-90 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:
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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.