Transcript Cardiovascular System

Cardiovascular System
Blood vessels, heart and blood
Functions
• Transport oxygen, nutrients, waste,
hormones
• White blood cells fighting disease
• Temperature regulation
Blood vessels
• Arteries carry blood away from the heart
• All (except the pulmonary artery) carry
oxygen-rich blood which is bright red
• Artery walls are thick and muscular
• Arteries expand and relax as the heart
beats
• This results in a pulse
• Arteries have high pressures
Pulse Points
Blood vessels
• Veins carry blood back to the heart
• Veins carry deoxygenated blood (except
the pulmonary veins) which is dark
reddish/blue
• Walls of veins are thin and pressures are
low
• Veins have valves to prevent backflow of
blood
Blood Vessels
• Capillaries are the tiniest of blood vessels
• Capillaries connect the arteries and the
veins
• Walls are very thin – only one cell layer
• Diffusion of substances (e.g. oxygen)
occurs through the walls of the capillaries
Lymph Vessels
• Lymph vessels travel near the veins and
carry fluids similar to blood but without the
red blood cells
• Eventually lymph vessels empty their
contents into large veins
• Lymph vessels travel through lymph nodes
that have the job of filtering the lymph
Heart
• “cardia-” means heart
• Located slightly left of center in your chest
cavity and surrounded by lungs on each
side
• Made of striated involuntary muscle
Heart chambers contain blood
• Left and right atrium (atria pl.)
• Left and right ventricle
Heart valves
• One way valves keep blood moving in one
direction
• As valves close, one hears the
characteristic “lub-dupp” sound of the
heart beating
• Valves between the atrium and ventricle
on each side
• Valves between the ventricles and the
arteries on both sides
Blood flow through heart
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Superior & Inferior Vena Cava
Right atrium
Right ventricle
Pulmonary artery to lungs
Pulmonary veins
Left atrium
Left ventricle
Aorta
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Vena Cava has deoxygenated blood
Pulmonary artery has deoxygenated blood
Pulmonary vein has oxygenated blood
Aorta has oxygenated blood
Coronary arteries
• The heart muscle itself gets its oxygen and
nutrients from the coronary arteries
• What would happen if a coronary artery
would get blocked?
Heart Physiology
• SA node is the pacemaker of the heart
• Located in the wall of the right atrium
• The SA node cardiac muscle cells contract
faster than all of the other heart muscle
cells and all cardiac muscle cells are
interconnected.
• The SA node sets the pace of the entire
heart and beats about 60-80 beats per
minute at rest.
Heart Physiology
• Heart muscle contraction is electrical, so
can be monitored with electrodes and
recorded as an ECG or EKG electrocardiogram
Cardiac Cycle
• The cardiac cycle is one complete heart
beat.
• Systole is the contraction phase when
blood is ejected from the heart ventricles
• Normal systolic pressure is 120 mm Hg
Cardiac Cycle
• Diastole is the relaxation phase of the
cycle
• Heart chambers refill with blood during
diastole
• While diastolic pressure is quite low in the
heart, it can be represented by measuring
an artery and normal is 80 mm Hg
Cardiovascular Pathology
• Hypertension is continuous high blood
pressure.
• > 160/95 mm Hg
• Affects 20 % of American Population
Hypertension
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Causes include heredity
Obesity
Stress
Smoking
Diet
• Arteriosclerosis is “hardening” of the
arteries
• Often a complication of hypertension
• Arteries become more susceptible to
getting an unwanted blood clot
Aneurysm
• Weakening and ballooning of an artery
• Can be a complication of hypertension
• Can lead to a burst artery which is very
serious
Coronary Artery Disease
• Excessive cholesterol can build up in the
wall of arteries – especially the coronary
arteries
• Saturated fats from the diet can build up
too
• Atherosclerosis is the condition of having
fatty plaques in the wall of an artery
Atherosclerosis is a fatty plaque
Heart Attack
• As coronary arteries become blocked, the
heart muscle dies from lack of oxygen and
nutrients
• Treatments include “clot busting” drugs,
angioplasty to open up clogged arteries
and bypass surgery around the blockage
Angina
• Chest pains due to heart muscle cells
being deprived of oxygen
• Often occurs after physical exertion
• Forewarning of worse things to come, like
a heart attack
Varicose Veins
• Damaged veins leading to overly
distended veins
• Damage to valves in the veins
• Varicose veins near the anus are called
hemorrhoids
• Treatments include anti-inflammatory
drugs, rest, vein injections and surgery