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Cardiovascular system. *The Cardiovascular System. A closed system of the heart and blood vessels The heart pumps blood Blood vessels allow blood to circulate to all parts of the body
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*The Cardiovascular System • A closed system of the heart and blood vessels • The heart pumps blood • Blood vessels allow blood to circulate to all parts of the body • The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products
The Heart Figure 11.1c
The Heart Figure 11.2a
The Heart: Coverings • Pericardium—a double-walled sac • Fibrous pericardium is loose and superficial • Serous membrane is deep to the fibrous pericardium and composed of two layers • Visceral pericardium • Next to heart; also known as the epicardium • Parietal pericardium • Outside layer that lines the inner surface of the fibrous pericardium • Serous fluid fills the space between the layers of pericardium
The Heart: Heart Wall Figure 11.2b
*The Heart: Heart Wall • Three layers • Epicardium • Outside layer • This layer is the visceral pericardium • Connective tissue layer • Myocardium • Middle layer • Mostly cardiac muscle • Endocardium • Inner layer • Endothelium
*The Heart: Chambers • Right and left side act as separate pumps • Four chambers • Atria • Receiving chambers • Right atrium • Left atrium • Ventricles • Discharging chambers • Right ventricle • Left ventricle
The Heart: Chambers Figure 11.2c
Differences in Right and Left Ventricles Figure 11.4
*The Heart: Valves • Allow blood to flow in only one direction to prevent backflow • Four valves • Atrioventricular (AV) valves—between atria and ventricles • Bicuspid (mitral) valve (left side of heart) • Tricuspid valve (right side of heart) • Semilunar valves—between ventricle and artery • Pulmonary semilunar valve • Aortic semilunar valve
The Heart: Valves Figure 11.2c
Operation of the AV valves Blood returning tothe atria, putspressure againstAV valves; the AVvalves are forcedopen As the ventriclesfill, AV valve flapshang limply intoventricles AV valves open Atria contract,forcing additionalblood into ventricles Ventricles (a) Figure 11.5a, step 3
The Heart: Conduction System • Special tissue sets the pace • Sinoatrial node = SA node (“pacemaker”), is in the right atrium • Atrioventricular node = AV node, is at the junction of the atria and ventricles • Atrioventricular bundle = AV bundle (bundle of His), is in the interventricular septum • Bundle branches are in the interventricular septum • Purkinje fibers spread within the ventricle wall muscles
Heart Contractions Figure 11.6
Heart Contractions • Contraction is initiated by the sinoatrial node (SA node) • Sequential stimulation occurs at other autorhythmic cells • Force cardiac muscle depolarization in one direction—from atria to ventricles
Heart Contractions • Once SA node starts the heartbeat • Impulse spreads to the AV node • Then the atria contract • At the AV node, the impulse passes through the AV bundle, bundle branches, and Purkinje fibers • Blood is ejected from the ventricles to the aorta and pulmonary trunk as the ventricles contract
*Systemic and Pulmonary Circulations • Systemic circulation • Blood flows from the left side of the heart through the body tissues and back to the right side of the heart • Pulmonary circulation • Blood flows from the right side of the heart to the lungs and back to the left side of the heart
Systemic and Pulmonary Circulations Figure 11.3
Pathway of blood through the body • Right ventricle • Pulmonary artery • Capillaries in lungs • Pulmonary vein • Left atrium • Left ventricle • Aorta • Artery • arteriole • Capillary (7,8) • Venule • vein • Vena cava (9,10) • Right atrium
*Comparison of blood pressure between arteries, veins and capillaries
Untreated hypertension • Left untreated, hypertension can cause: • Stroke (brain attack) • Arteriosclerosis • Heart attack (myocardial infarction) • Kidney failure
Lab tests used before beginning hypertension treatment • used to determine organ or tissue damage or other risk factors. • These lab tests include • urinalysis, • blood cell count, • blood chemistry (potassium, sodium, creatinine, fasting glucose, total cholesterol and HDL cholesterol), and an • ECG (electrocardiogram).
Untreated hypertension can also cause an aneurysm • This is an angiogram of a person with an aortic aneurysm. • If this aorta ruptures, death occur in less than 2 minutes.
How do you treat Hypertension? • Because pressure is related to volume, drugs will either try to: • Increase the volume of the vessels • Decrease the volume of the blood. • Diuretics • Bumex, Midamor • Anti-Adrenergics • Beta blockers • Block the action of epinepherine • Toprol • Vasodilators • minoxidil
aneurysms 25% • A balloon like bulge in an artery. • Thick artery walls can be damaged by… • Trauma, medical problems, genetic conditions. • When it bursts it is usually fatal. 75% http://www.nhlbi.nih.gov/health/dci/Diseases/arm/arm_types.html
Peripheral vascular disease • Reduced blood flow can cause pain and numbness. • Increases infection risk. • Can cause gangrene. • Leg pain when you walk or climb stairs • Smoking increases risk 4X. • Increases risk of MI 6X http://www.nhlbi.nih.gov/health/dci/images/pad_plaque.jpg
Deep vein thrombosis • animation