chapter learning objectives 17.1-17.5

  Describe the position of the heart in the thoracic cavity

heart is situated in the chest slightly to the lt side in a subivision of the thoracuc cavity

describe the basic surface anatomy of the chambers of the heart

heart consists of 4 hollow chambers: superior rt and lt atria and inferior rt abd lt ventricles

explain how the hearts functions as a double pump and why this is significant

the heart functions as a duble pump because it is divided into functionally into rt and lt sides.

Rt side pumps deoxygenated blood to the lungs (pulmonary circuit)

lt side pumps oxygenated blood to rest of the body (systemic circuit)

17.2 heart anatomy and blood flow pathway

describe the layers of the pericardium and heart wall

fibrous pericardium- a saw w/ 2 components a tough outer layer that attaches the heart to surrounding structures

serous pericardium-thin inner serous membrane that produces serous fl

parietal pericardium-outer layer is fused to the inner surface of the fibrous pericardium

visceral pericardium- inner layer aka epicardium

Describe the location and function of the coronary circulation and great vessels

great vessels-bring blood to and away from the heart, are the largest ones in the body

coronary circulation-set of arteries, veins, and capillaries that supply blood to and drain blood from the myocardium of the heart

Describe the structure and function of the chambers, septa,valves, and other structural features of the heart

Trace the pathway of blood flow through the heart, and explain how structures of the heart ensure that blood flows in a single direction

figure 17.8

17.3 Cardiac muscle tissue anatomy and elctrophyiology

Describe the histology of cardiac muscle tissue, and differentiate it from that of skeletal muscle

cardiac muscle cells have striations, means that the cells have alternating light and dark bands

skeletal muscle cells results from fusion of multple immature myoblast, causing to form long multinucleated fibers as for cardiac muscle cells they are short, wide cells, that contain a signle nucleus

Describe the phases of the cardiac muscle cell action potential, including the ion movements that occur in each phase, and explain the importance of the plateau phase

Contrast the way action potentials are generated in cardiac pacemaker cells, cardiac contractile cells, and skeletal muscle cells

Describe the parts of the cardiac conduction system, and explain how the system functions

SA node, AV node, Purkinje fiber system

SA node:cluster of pacemaker cells in the sup RA that normally sets the pace for the heart

AV node: cluster of pacemaker cells in the Inf RA that delays the propagation of the cardiac action potential from the atria to the ventricles

Purkinje fibers: group of atypical pacemaker cells located in the ventricles

Identify the waveforms in a normal electrocardiogram (ECG), and relate the ECG waveforms to electrical activity in the heart

17.4 Mechanical Physiology of the Heart: cardiac cycle

Describe the phases of the cardiac cycle (17.17)

ventricular filling phase

isovolumetric contraction phase

ventricular ejection phase'

isovolumetric relaxation phase

Relate the opening and closing of specific heart valves in each phase of the cardiac cycle to pressure changes in the heart chambers

17.17

Relate the heart sounds and ECG waveforms to the normal mechanical events of the cardiac cycle

17.20

Compare and contrast pressure and volume changes of the left and right ventricles and the aorta during one cardiac cycle

17.18

17.5 Cardiac Output and Regulation

Define and calculate cardiac output, given stroke volume, heart rate, and end-diastolic and end-systolic volumes

CO: the vol. of blood pumped itno the pulmonary and systemic circuits in 1 min

ex: EDV-ESV=SV

120 mL-50mL=70mL

find the CO:

72 bpm*70mL/beat=5040 mL/min or 5 L/min

HR * SV= CO

Describe the factors that influence preload, afterload, and contractility, and explain how they affect cardiac output

preload: imposed on the heart before it contracts

contractility: ability to generate tension

afterload: agaisnt which the heart pumps as it contracts

preload involves EDV whereas contractility ans afterload afftect the ESV

Explain the significance of the Frank-Starling law for the heart

the signigicance of Frank-Starling low of the heart is cardica physiology that describes how the hearts SV is influenced by the degree of stretch of the ventricular muscle cells before contraction

Discuss the influence of positive and negative inotropic and chronotropic agents on stroke volume and heart rate, respectively

Predict how changes in heart rate and/or stroke volume will affect cardiac output

increase in afterload therefore generaaly causes a decrease in SV, which in turn leads to a rise in the ESV of the ventricles.

decrease in afterload generally corresponds to a higher SV and a lower ESV