1. Chapter 13: The Heart

2. Circulation and the Heart
Continuous one-way circuit of the blood vessels
Propelled by heart

3. Location of the Heart Between the lungs
Left of the midline of the body
In mediastinum
Apex pointed toward left

4. The heart in position in the thorax (anterior view).  

5. Structure of the Heart Three tissue layers
Endocardium lines heart’s interior
Myocardium is thickest layer; the heart muscle
Epicardium is thin outermost layer

6. The Pericardium The sac that encloses the heart
Fibrous pericardium holds heart in place
Serous membrane
Parietal layer
Pericardial cavity
Visceral layer (epicardium)

7. Special Features of the Myocardium
Cardiac muscles
Are lightly striated (striped)
Have single nucleus cells
Are controlled involuntarily
Have intercalated disks
Modified plasma membranes
Have branching muscle fibers

8. Divisions of the Heart Double pump
Right side pumps blood low in oxygen to the lungs
Pulmonary circuit
Left side pumps oxygenated blood to remainder of body
Systemic circuit
Divisions of the Heart

9. Four Chambers Right atrium
Receives low-oxygen blood returning from body tissue through superior vena cava and inferior vena cava
Left atrium
Receives high-oxygen blood from lungs
Right ventricle
Pumps blood from right atrium to lungs
Left ventricle
Pumps oxygenated blood to body

11. The heart and great vessels.

12. Four Valves Atrioventricular valves Entrance valves
Right atrioventricular (AV) valve (tricuspid valve)
Left atrioventricular (AV) valve (bicuspid valve)
Attached by threads (chordae tendinae) to papillary muscles
Semilunar valves
Exit valves
Pulmonary valve
Aortic valve

13. Pathway of blood through the heart.

14. Blood Supply to the Myocardium
Coronary circulation-own blood supply
Right coronary artery
Left coronary artery
These arteries are the first to branch off from the aorta
After passing through capillaries in the myocardium, blood drains into a system of cardiac veins that bring blood back to the R atrium
Coronary sinus
Dilated vein that opens into the R atrium near IVC
Blood colllects here

15. Blood vessels that supply the myocardium
Blood vessels that supply the myocardium. Coronary arteries and cardiac veins are shown. (A) Anterior view. (B) Posterior view.

16. Function of the Heart
Left and right sides of heart work together in cardiac cycle (heartbeat)
Systole (active phase, contraction)
Diastole (resting phase)

17. The cardiac cycle.

18. Cardiac Output Calculating cardiac output Cardiac output (CO)
Stroke volume (SV)
Heart rate (HR)
CO = HR 3 SV

19. The Heart’s Conduction System
Electrical energy stimulates heart muscle
Nodes
Sinoatrial (SA) node (pacemaker)
Atrioventricular (AV) node
Specialized fibers
Atrioventricular bundle (bundle of His)
Purkinje fibers (conduction myofibers)
Intercalated disks

20. The Conduction Pathway
Sinus rhythm
Sinoatrial (SA) node
Atria
Atrioventricular (AV) node
Internodal pathways
Bundle of His
Bundle branches and Purkinje fibers
Ventricles

21. Conduction system of the heart.

22. Control of the Heart Rate
Influences that allow heart to meet changing needs rapidly
Autonomic nervous system (ANS)
Sympathetic nervous system
Parasympathetic system
Cranial nerve X

23. Variations in Heart Rates
Bradycardia
Tachycardia
Sinus arrhythmia
Premature beat (extrasystole)

24. Heart Sounds
Lub
Dup
Murmurs
Organic
Functional

25. The Heart in the Elderly
How the heart can age
Heart shrinks
Decreased contraction strength
Valves become less flexible
Murmur develops
Cardiac output decreases
Abnormal rhythms
Heart block

26. Maintaining Heart Health
Risk factors that cannot be modified
Age
Gender
Heredity
Body type
Risk factors that can be modified
Smoking
Physical inactivity
Weight
Diet
Blood pressure
Diabetes
Gout

27. Heart Studies Stethoscope Electrocardiograph (ECG or EKG) Electrodes
Catheterization
Fluoroscope
Echocardiography (ultrasound cardiography)
Oscilloscope

28. Figure 13-12 Coronary angiography.28

29. Normal ECG tracing.