Transcript SBI3U_04_10_Circulatory_Health

Circulatory System
Health
Electrocardiogram (ECG/EKG)
• Detects the heart’s
electrical activity
through electrodes
attached to the skin.
• Graphically represents
the various parts of an
individual’s cardiac
cycle.
The Cardiac Cycle
• P wave: reflects atrial
contraction.
• QRS complex: reflects
ventricular contraction.
• T wave: reflects
ventricular relaxation.
Blood Pressure
• The pressure exerted on the arterial walls.
• The elastic property of vessels allows for
continuous blood flow throughout the circulatory
system.
• The difference between systolic pressure and
diastolic pressure is called pulse pressure.
Blood Pressure
• Highest pressure in aorta.
• Blood pressure and velocity both decline as
blood enters the arterioles.
• The drop in pressure results from the
resistance (friction) to blood flow.
• Low blood pressure – reduces the body’s
capacity to transport blood.
• High blood pressure – can weaken and
rupture the arterial walls.
Blood Pressure
Blood Pressure
• Normal, healthy human
blood pressure ranges
between 100 – 140 mm
Hg for Systolic pressure
and between 70 – 90 mm
Hg for Diastolic pressure.
• On average, normal,
healthy human blood
pressure (bp) is 120/80.
• Taking one’s blood
pressure can be a way to
detect signs of heart
problems.
Hypertension
• Hypertension is High Blood Pressure.
• Diagnosed when high bp stays above 140/90 for
a prolonged period.
• Can be caused by
many factors, most of
which are controllable.
• Can cause coronary
heart disease
(stroke, heart attack, etc.)
Hypertension Relief
What’s needed?
• Decrease cardiac output and lower pressure in
arterioles, which can be accomplished by:
– Improved nutrition
– Regular exercise
– Medication
• Lowering blood pressure will help return restore
homeostasis in the body.
Hypertension Medications
Vasodilators
• Widen blood vessels so that there is less
pressure and resistance in them.
Diuretics
• Cause body to increase urination, which reduces
body fluid.
• Less body fluid means less fluid to create
pressure, so blood pressure decreases.
Hypotension
• Hypertension is Low Blood Pressure.
• Diagnosed when high bp stays below 90/60 for a
prolonged period.
• Low blood pressure, with no symptoms, is not
considered unhealthy.
Symptoms:
- lightheadedness, dizziness, fainting
- confusion, fatigue, thirst
Possible causes:
- medications, hormone imbalance, shock
• Could also lead to coronary heart disease (stroke,
heart attack, etc.)
Atherosclerosis
• Caused by build up of plaque along the walls of blood
vessels.
• Plaque is an accumulation of cholesterol and lipids
(you are what you eat!)
• Interrupts blood flow.
• Reduces O2 and nutrients getting
to tissues further away.
• Can form clots that block blood
flow in vessels altogether.
• Can lead to heart attack or stroke.
• Coronary arteries are
particularly susceptible.
Heart Attack
• A clot completely blocks a coronary artery, causing
death to some cardiac muscle cells.
• Heart is weakened and unable to pump as efficiently.
Associated symptoms:
– fatigue
– dizziness or light-headedness
– indigestion
• Scar tissue where damage was located may continue
to interfere with coronary circulation, preventing other
areas of the heart from receiving enough O2, and
increasing the risk of another heart attack.
Heart Attack
Risk Factors:
• Age
• Smoking*
• Poor diet (poor nutrition)*
• Obesity*
• Lack of exercise*
• Family history of
heart disease
• Stress*
• Diabetes*
* can be controlled
Stroke
• A result of a damaged blood vessel (usually one supplying
blood to the brain).
Hemorrhagic: Blood vessel
bursts due to high pressure in
the vessel and hemorrhage
(internal bleeding) occurs in
the brain.
Ischemic: A clot in a blood
vessel prevents the blood
supply (and thus, O2) from
reaching the brain, and brain
tissue dies.
Stroke Symptoms
• Can vary depending on which vessel is affected.
• Typically experienced on the opposite side of the body
from the affected side of the brain.
• Sometimes symptoms are reversible, sometimes they
are permanent.
Common symptoms (warning signs) include:
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Sudden weakness or numbness
Sudden severe headache
Sudden dizziness or loss of balance
Sudden vision problems
Slurred speech or comprehension difficulty, confusion
Affects of Nicotine
• Stimulant substance in tobacco and very
addictive.
• Effects include a rise in blood pressure and an
increase in heart rate.
• Combined with tar and carbon monoxide in
cigarettes, nicotine poses serious health risks for
heart disease, in addition to lung cancer.
Smoking & Arteries
Technologies in Diagnosing
• Medical research and advances in technology have
established various methods for detecting and
diagnosing coronary heart disease.
Exercise Stress Test
– Individual walks or runs on
a treadmill, which increases
in speed and incline.
– ECG readings, blood pressure,
and physical symptoms
(e.g., shortness of breath or
angina) are monitored.
Nuclear Medicine
– Radioactive thallium201 is injected during a stress test and
pattern of radioactive decay in coronary arteries is examined.
Technologies in Diagnosing
Cardiac Catheterization
– A catheter is inserted in
femoral artery and guided
through arterial system into
coronary arteries of heart.
– Dye is injected, which fills
coronary arteries.
– An angiogram (special X-ray)
is taken of blood vessels that
can reveal location of
blockages.
Cardiac Surgery
Angioplasty
• A small balloon is inserted through cardiac catheter.
• Balloon is inflated to help dilate the coronary arteries.
Bypass Surgery
• A portion of vein (often from
the leg) is used to create a
shunt (alternate pathway)
between sections of coronary
arteries to allow circulation to
bypass an arterial blockage.
Exercise for Heart
• Exercising muscles increases rate of cellular
respiration – produces more CO2 and lactic acid.
• Blood pH becomes more acidic, causing blood
vessels to dilate, while stimulating deeper
breathing to replenish O2 in the blood.
• Heart rate increases, so oxygenated blood is
pumped more efficiently throughout body.
• Regular exercise increases body’s capacity to
utilize oxygen (e.g., 10% more in athletes).
Benefits of Regular Exercise
• Reduces risk of developing heart disease.
• Strengthens heart, lungs, and bones.
• Muscles become toned giving more shape to
the body.
• Diabetes can be significantly controlled, as
exercise helps maintain blood sugar levels.
• Additional benefits include: improved
concentration and memory, and a reduction in
stress levels.
Heart & Stroke Foundation