I.    General Characteristics of Cardiovascular System
        Artery - vessel which carries blood AWAY from the heart
        Vein - vessel which carries blood TOWARD the heart

        Whether a vessel is an artery or vein has nothing to do with the concentration of
        oxygen in the blood

        The cardiovascular system consists of 2 parallel circuits:
        1) pulmonary
        2) systemic
        both circuits pump the same volume of blood per cardiac cycle, but the
        pulmonary circuit is low pressure, whereas the systemic circuit is high pressure

        Cardiac Cycle - know events of the cardiac cycle in terms of:
        1. atrial and ventricular systole and diastole
        2. ECG events
        3. opening, closing of AV, semilunar valves (heart sounds)

II.    Chapter 40 - Anatomy of the Heart
        A.    Ex 40-1: Chambers - 4

• right atrium (and auricle) - storage of blood
• left atrium (and auricle) - storage of blood
• right ventricle - thinner walled, pumps to pulmonary circuit
• left ventricle - this is thicker walled, why?
• ventricular septum

• epicardium - is the visceral layer of the pericardium
• myocardium - is the thick muscular walls
• endocardium - is a delicate layer of epithelial cells that line the inside of the heart and are continuous with the lining of the blood vessels

• Fibrous pericardium - outermost layer
• composed of thick, dense connective tissue
• attached to central tendon of diaphragm —why?
• Parietal pericaridum - intermediate layer
• lines the inside of the fibrous pericardium
• Visceral pericardium - innermost layer
• closely applied to the heart muscle, reflects downward at base
• essentially the heart develops/ grows into this balloon-like layer.

    C.    Ex 40-1: Coronary Circulation
            1.    Coronary Arteries

• Right Coronary - supplies the post surface of the ventricles and lat. right side. through its branches the rt. cicumflex & post. interventricular.
• Left Coronary - supplies ant. vent and lat/dorsal walls through branches ant. interventricular & marginal.

• Great cardiac - runs around left side to enter sinus
• Rt. coronary - parallels right coronary a. into sinus
• Middle cardiac - parallels posterior interventricular a.
• Lt. post. ventricle - extends along left ventricle
• Coronary sinus - receives blood from other 4 vns

• Aorta - arches up from LV., has 3 branches
• brachiocephalic, left common carotid, left subclavian
• Pulmonary Trunk - exits RV and splits into R/L pulmonary arteries to the lungs

• Pulmonary veins (4) - return blood to LA from lungs

• Atrioventricular Valves(2) -prevent back-flow into the atria when the ventricles are contracting
• Mitral(bicuspid) - located between the left atrium and ventricle, consists of two flaps of endocardium
• Tricuspid - located between the right atrium and ventricle, consists of 3 flaps of endocardium, prevents back-flow
• Chordae tendinae - are collagen-like cords that anchor the cusps to the ventricular walls.
• Papillary muscles - small bundles of cardiac muscle that give rise to the chordae tendinae, arise from the ventricular wall.
• Pulmonary and Aortic Semilunar valves
• Each composed of 3 pocket-like cusps which are flattened against the arterial walls during contraction
• Pulmonary Semilunar valve - between RV and pulmonary trunk
• Aortic Semilunar valve - between LV and aorta

II.    Chapter 41 - Cardiac Activity
    A.    Ex 41-1: Heart Sounds (Auscultation)
                Lubb - 1st heart sound, due to closing of AV valves
                usually louder because they are closer to surface
                Dupp - 2nd heart sound, due to closing of semilunar valves

• Starling’s Law of the Heart: Stroke volume is directly proportional to venous return - the more blood that returns to the heart, the more the cardiac muscle fibers are stretched, leading to a more powerful recoil of the ventricles to eject blood, and therefore a larger stroke volume. As more blood returns to fill the heart, more blood is available to be ejected during contraction. In addition, increased venous return stretches the fibers within the SA node, leading to an increase in heart rate.

• Autonomic Nervous System
• Sympathetic (norepinephrine)- increase heart rate, contractility
• Parasympathetic (acetylcholine) - decrease heart rate, small effect on contractility
• Hormonal - epinephrine, norepinephrine secreted from adrenal medulla
• Chemoreceptors and Baroreceptors - sense blood pressure, the concentration of oxygen/carbon dioxide, pH of blood

• autorhythmic cells - equal about 1% of heart cells. They spontaneously depolarize at regular intervals to control heart rate.
• Components of the intrinsic conduction system
• SA(sinoatrial) node
• AV(atrioventricular) node
• AV bundle (bundle of HIS) - splits left and right bundle branches
• Purkinje fibers

• P wave - indicates depolarization of atria immediately before atrial contraction
• QRS complex - precedes ventricular contraction, signals ventricular depolarization
• T wave - signifies the repolarization of the ventricles

• PR interval - represents the time between atrial depolarization and ventricular depolarization
• Too long - may represent AV node damage.
• Total heart block - atria and ventricles beat independently of one another.
• QT interval - represents the period between the beginning of ventricular depolarization through repolarization
• normal HR is approx. 70bpm so QT is usually 0.31-0.41 sec, in duration.
• If HR increases - QT becomes shorter
• If HR decreases - QT becomes longer
• Tachycardia - HR over 100 bpm. Can lead to fibrillation if sustained over long periods
• Bradycardia - HR under 60 bpm. good in conditioned athletes, otherwise it can lead to O2 deprivation of the brain.
• ECG - only tests to see if the electrical conduction system is working properly, you still need to ausculate to determine if valves and pumps are working correctly.

• Be familiar with all the anatomic terms discussed in lecture
• Be able to identify the major anatomical features on models and sheep hearts
• Follow the instructions for sheep heart dissection on pp. 464-466

• Identify the 2 major heart sounds and be sure you can hear them on your lab partner.
• Handout
• Use the CD-ROM program, "Effects of Drugs on the Frog Heart" to observe the effects of various types of drugs on heart function

• be familiar with the conduction system of the heart
• be able to read an EKG and determine if it is normal or not
• be able to calculate heart rate from an EKG