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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
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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
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 • Superior & Inferior Vena Cava • Right atrium • Right ventricle • Pulmonary artery to lungs • Pulmonary veins • Left atrium • Left ventricle • Aorta
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 • 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
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