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Chapter 12 The Cardiovascular System. * function: circulate blood throughout entire body: – transport O 2 and nutrients (glucose) to cells – transport.

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Presentation on theme: "Chapter 12 The Cardiovascular System. * function: circulate blood throughout entire body: – transport O 2 and nutrients (glucose) to cells – transport."— Presentation transcript:

1 Chapter 12 The Cardiovascular System

2 * function: circulate blood throughout entire body: – transport O 2 and nutrients (glucose) to cells – transport CO 2 and wastes (urea) away from cells – transport immune system cells and antibodies – transport hormones to target cells

3 * consists of 2 components:

4 heart “cardio” - pumps blood

5 blood vessels “ vascular” - carry blood

6 * 2 circuits:

7 pulmonary circuit

8 right side of heart lung capillaries left side of heart

9 systemic circuit

10 left side of heart body tissue capillaries right side of heart

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13 Clotting Groups Pressure Donation Forum Links The Team Awards Disclaimer Linksystem Profile Sign Out

14 12.1 Anatomy of the Heart

15 * located in thoracic cavity between lungs

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17 A. The Wall and Coverings of the Heart

18 1. pericardium- serous membrane, covers the heart

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20 2. myocardium – cardiac muscle, wall of heart

21 3. endocardium – inner lining of heart

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23 B. Chambers of the Heart

24 1. Right Atrium * right upper chamber of heart * receives deoxygenated blood from body (venae cavae) tricuspid (R-AV) valve right ventricle

25 2. Right Ventricle * right lower chamber of heart * pumps deoxygenated blood pulmonary semilunar valve pulmonary arteries lungs

26 3. Left Atrium * left upper chamber of heart * receives oxygenated blood from lungs (pulmonary veins) bicuspid (mitral) valve left ventricle

27 4. Left Ventricle * left lower chamber of heart * pumps oxygenated blood aortic semilunar valve aorta body

28 Right Atrium Right Ventricle Left Atrium Left Ventricle Interventricular Septum Heart Chambers

29 Tricuspid Valve Bicuspid Valve Pulmonary Semilunar Valve Aortic Semilunar Valve Chordae Tendinae Heart Valves

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32 Pulmonary Arteries Aorta Heart Blood Vessels Superior Vena Cava Left Pulmonary Veins Right Pulmonary Veins Inferior Vena Cava

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34 C. Operation of the Heart Valves 1. AV valves are normally open, they close when ventricles contract. 2. Semilunar valves are normally closed, they open when ventricles contract

35 D. Coronary Circuit 1. Heart muscle gets blood supply from the coronary arteries, and drains into coronary veins

36 2. Coronary Circuit Disorders: a. atherosclerosis / plaque = fatty deposits in coronary arteries b. ischemic heart disease = insufficient blood supply to heart c. thromboembolism = blood clot stuck in coronary artery d. angina pectoris = chest pain left arm e. myocardial infarction = damage to myocardium “heart attack”

37 3. Surgical Procedures a. balloon angioplasty = balloon inflates to open up a clogged coronary artery b. coronary bypass operation = portion of blood vessel from another part of body is used to bypass blocked coronary arteries

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41 12.2 Physiology of the Heart

42 A. Conduction System of the Heart * electrical system of the heart * causes contraction of the heart muscle * controlled by brain autonomic NS

43 1. Nodal Tissue

44 a. SA (sinoatrial) node * upper posterior wall of right atrium * initiates heartbeat “pacemaker” * causes atria to contract

45 b. AV (atrioventricular) node * base of right atrium near septum * “relay station” AV bundle “bundle of HIS” bundle branches Purkinje fibers * causes ventricles to contract

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52 2. Electrocardiogram (ECG) * graph: records electrical activity of heart

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54 * consists of a set of waves:

55 P = depolarization (contraction) of atria

56 QRS = depolarization (contraction) of ventricles

57 T = ventricles repolarize (recover)

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59 Electrocardiogram ] Intervals show timing of cardiac cycle P-P = one cardiac cycle P-Q = time for atrial depolarization Q-T = time for ventricular depolarization T-P = time for relaxation

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62 B. Cardiac Cycle and Heart Sounds

63 1. cardiac cycle * events that occur during one heartbeat systole = contraction of heart muscle diastole = relaxation of heart muscle

64 * 3 phases:

65 1. atrial systole atria contract (blood is forced into ventricles) venrtricles relaxed AV valves open, semilunar valves closed

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67 2. ventricular systole ventricles contract (blood forced out of heart) atria are relaxed AV valves close “lubb”, semilunar valves open

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69 3. atrial and ventricular diastole atria and ventricles are relaxed blood flows from atria to ventricles AV valves open, semilunar valves close “dup”

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72 2. Heart Sounds * caused by the closing of the heart valves * “lubb-dup”

73 C. Cardiac Output (CO)

74 * volume of blood pumped out of a ventricle in one minute * dependent on 2 factors: Heart Rate (HR) - beats per minute Stroke Volume (SV) - amount of blood

75 A Simple Model of Stroke Volume Figure 20.19a-d

76 Factors Affecting Cardiac Output Figure 20.20

77 Cardiac Output: An Example CO (ml/min) = HR (75 beats/min) x SV (70 ml/beat) CO = 5250 ml/min (5.25 L/min) If HR increases to 150 b/min and SV increases to 120 ml/beat, then – CO = 150 b/min x 120 ml/beat – CO = 18,000 ml/min or 18 L/min (WOW is right!!)

78 12.3 Anatomy of Blood Vessels

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80 A. Arteries and Arterioles * transport blood away from heart * usually transport oxygenated blood * thick, strong, elastic walls * 3 layers (tunic = coat):

81 tunica interna (intima) - inner layer, endothelium

82 tunica media - middle layer (thick), sm. muscle

83 tunica externa (adventitia) - outer layer, CT

84 * arterioles = small arteries

85 B. Capillaries * microscopic blood vessels * join arterioles to venules * site of gas/nutrient/waste exchanges

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88 C. Veins and Venules * transport blood toward the heart * usually transport deoxygenated blood * walls are much thinner (same 3 layers)

89 Fig A V Tunica adventitia Tunica media Tunica intima

90 * some veins have valves (arms, legs)

91 * venules = small veins

92 Direction of blood flow in vessels: Arteries  Arterioles  Capillaries  Venules  Veins

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95 12.4 Physiology of Circulation

96 A. Velocity of Blood Flow * fastest in arteries, slowest in capillaries Velocity of blood flow (mL/s) Blood Vessels

97 B. Blood Pressure * force of blood against a vessel wall * force of blood against a vessel wall * decreases with distance from left ventricle * decreases with distance from left ventricle * 2 factors that affect BP: * 2 factors that affect BP:

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100 cardiac output – HR and SV peripheral resistance – arterial diameter and length

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102 * Avg. BP in young adult = 120/80 top number = systolic pressure bottom number = diastolic pressure

103 * venous return depends on:   skeletal muscle pump – muscles squeeze   respiratory pump - breathing movements

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105 valves in veins valves in veins

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107 C. Evaluating Circulation

108 1. Pulse * surge/wave of pressure in an artery * surge/wave of pressure in an artery * = heart rate (bpm) * = heart rate (bpm)

109 * pulse points can be felt in arteries close to skin

110 2. Blood Pressure * = force of blood (mm Hg) * = force of blood (mm Hg) * measured with a sphgmomanometer * measured with a sphgmomanometer

111 Steps for measuring BP Apply cuff above elbow Place stethoscope on brachial artery Inflate cuff until pulse disappears

112 Steps for measuring BP cont. Let air out gradually Listen for sounds that blood is moving past cuff

113 systolic pressure = pressure when 1 st sound is heard diastolic pressure = pressure when last sound is heard

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116 * hypertension = 140/90

117 12.5 Circulatory Routes

118 A. The Major Systemic Arteries * see p.243 * see p.243

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120 B. The Major Systemic Veins * see p.244 * see p.244

121 C. Special Systemic Circulations

122 * hepatic portal system = from stomach/intestines to liver from stomach/intestines to liver

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124 * = brain * cerebral arterial circle = brain

125 * = * fetal circulation = fetus (no circulation to lungs) fetus (no circulation to lungs)

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