1. The Human Heart

2. The heart is a muscular double pump
Two functions
Pulmonary circuit: Right side receives oxygen-poor blood from the body and pumps it to the lungs
Systemic circuit: Left side receives oxygenated blood from lungs and pumps throughout the body 2

3. The Heart Atria Ventricles
Receive blood from the pulmonary and systemic circuits
Ventricles
The pumping chambers of the heart 3

4. Figure 19.1 The heart as a double pump.
Pulmonary Circuit
Capillary beds of lungs where gas exchange occurs
Aorta and branches
Pulmonary arteries
Left atrium
Pulmonary veins
Right atrium
Heart
Right ventricle
Left ventricle
Systemic Circuit
Venae cavae
Capillary beds of all body tissues where gas exchange occurs
Oxygen-rich, CO2-poor blood
Oxygen-poor, CO2-rich blood

5. Figure 19.2 Location of the heart in the thorax.
Superior vena cava
Midsternal line
Aorta
Rib 2
Parietal pleura (cut)
Diaphragm
Pulmonary trunk
Left lung
Pericardium (cut)
Mediastinum
Apex of heart
Heart
Diaphragm
Right lung T8
Posterior
Mediastinum
Aorta
Superior vena cava
Left lung
Fat in epicardium
Right auricle of right atrium
Rib 5
Right ventricle
Pericardium (cut)
Apex of heart

6. Structure of the Heart—Coverings
Pericardium—two primary layers
Fibrous pericardium
Strong layer of dense connective tissue
Serous pericardium
Formed from two layers
Parietal layer of the serous pericardium
Visceral layer of the serous pericardium 6

7. Figure 19.3 The layers of the pericardium and of the heart wall.
Pulmonary trunk
Fibrous pericardium
Parietal layer of serous pericardium
Pericardium
Pericardial cavity
Myocardium
Epicardium (visceral layer of serous pericardium)
Heart wall
Myocardium
Endocardium
Heart chamber

8. Layers of the Heart Wall
Epicardium
Visceral layer of the serous pericardium
Myocardium
Consists of cardiac muscle
Muscle arranged in circular and spiral patterns
Endocardium
Endothelium resting on a layer of connective tissue
Lines the internal walls of the heart 8

9. Right and left ventricles
Heart Chambers
Right and left atria
Superior chambers
Right and left ventricles
Inferior chambers
Internal divisions
Interventricular septa
Interatrial septa 9

10. Figure 19.5b Gross anatomy of the heart.
Left common carotid artery
Brachiocephalic trunk
Left subclavian artery
Superior vena cava
Aortic arch
Ligamentum arteriosum
Right pulmonary artery
Left pulmonary artery
Ascending aorta
Pulmonary trunk
Left pulmonary veins
Auricle of left atrium
Right pulmonary veins
Circumflex artery
Right atrium
Right coronary artery (in coronary sulcus)
Left coronary artery (in coronary sulcus)
Anterior cardiac vein
Left ventricle
Right ventricle
Great cardiac vein
Right marginal artery
Anterior interventricular artery (in anterior interventricular sulcus)
Small cardiac vein
Inferior vena cava
Apex
Anterior view

11. Path of Blood Flow
Through Heart

12. Forms right border of heart
Right Atrium
Forms right border of heart
Receives oxygen-poor blood from systemic circuit through these vessels:
Superior vena cava
Inferior vena cava 12

13. Pumps blood into pulmonary circuit the pulmonary trunk
Right Ventricle
Receives blood from right atrium through the right atrioventricular valve (tricuspid valve)
Pumps blood into pulmonary circuit the pulmonary trunk 13

14. Internal walls of right ventricle
Trabeculae carneae
Papillary muscles
Chordae tendineae
Pulmonary semilunar valve (pulmonary valve)
Located at opening of right ventricle and pulmonary trunk
Papillary muscle 14

15. Makes up heart’s posterior surface
Left Atrium
Makes up heart’s posterior surface
Receives oxygen-rich blood from lungs through pulmonary veins
Opens into the left ventricle through
Left atrioventricular valve (bicuspid valve)
Mitral valve is another name for the left AV valve
Bicuspid valve is another name for this. 15

16. Forms apex (lower tip) of the heart Internal walls of left ventricle
Trabeculae carneae
Papillary muscles
Chordae tendineae
Pumps blood through systemic circuit via
Aortic semilunar valve (aortic valve) 16

17. Figure 19.5e Gross anatomy of the heart.
Aorta
Left pulmonary artery
Superior vena cava
Left atrium
Right pulmonary artery
Left pulmonary veins
Pulmonary trunk
Right atrium
Mitral (bicuspid) valve
Right pulmonary veins
Fossa ovalis
Aortic valve
Pectinate muscles
Pulmonary valve
Tricuspid valve
Right ventricle
Left ventricle
Chordae tendineae
Papillary muscle
Interventricular septum
Trabeculae carneae
Epicardium
Inferior vena cava
Myocardium
Endocardium
Frontal section

18. Posterior View Aorta Superior vena cava Right pulmonary artery
Left pulmonary artery
Right pulmonary veins
Left pulmonary veins
Auricle of left atrium
Right atrium
Left atrium
Inferior vena cava
Great cardiac vein
Coronary sinus
Right coronary artery (in coronary sulcus)
Posterior vein of left ventricle
Posterior interventricular artery (in posterior interventricular sulcus)
Left ventricle
Middle cardiac vein
Right ventricle
Apex
Inferior view; surface shown rests on the diaphragm.

19. Heart Valves—Valve Structure
Each valve composed of
Endocardium with connective tissue core
Atrioventricular (AV) valves
Between atria and ventricles
Right AV valve  tricuspid valve
Left AV valve  bicuspid (mitral) valve
Aortic and pulmonary valves
At junction of ventricles and great arteries 19

20. Figure 19.7a Function of the atrioventricular valves. (1 of 2)
Ventricle
Direction of blood flow
Atrium
Cusp of atrioventricular valve (open)
Chordae tendineae
Papillary muscle
AV valves open; atrial pressure greater than ventricular pressure
Blood returning to the heart fills atria, pressing against the AV valves. The increased pressure forces AV valves open.
As ventricles fill, AV valve flaps hang limply into ventricles.
Atria contract, forcing additional blood into ventricles. 1 2 3

21. Figure 19.7b Function of the atrioventricular valves. (1 of 2)
Atrium
Cusps of atrioventricular valve (closed)
Ventricles contract, forcing blood against AV valve cusps. 1 2
AV valves close.
Blood in ventricle
Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from
everting into atria. 3
AV valves closed; atrial pressure less than ventricular pressure

22. Figure 19.8 Function of the semilunar valves.
Aorta
Pulmonary trunk
As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open.
Semilunar valves open
As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close.
Semilunar valves closed

23. “Lub-dup”—sound of valves closing
Heart Sounds
“Lub-dup”—sound of valves closing
First sound: “lub”
The AV valves closing
Second sound: “dup”
The semilunar valves closing 23

24. Pathway of Blood Through Heart

25. Figure 19.10 The heart is a double pump, each side supplying its own circuit.

26. 70–80 beats per minute at rest
Heartbeat
70–80 beats per minute at rest
Systole—contraction of a heart chamber
Diastole—expansion of a heart chamber
Systole and diastole also refer to
Stage of heartbeat when ventricles contract and expand 26

27. Structure of Heart Wall
Walls differ in thickness
Atria—thin walls
Ventricles—thick walls
Systemic circuit
Longer than pulmonary circuit
Offers greater resistance to blood flow 27

28. Structure of Heart Wall
Left ventricle
Three times thicker than right ventricle
Exerts more pumping force
Right ventricle
Left ventricle
Interventricular septum 28

29. Not all cardiac cells are innervated
Cardiac Muscle Tissue
Not all cardiac cells are innervated
Will contract in rhythmic manner without innervation
Inherent rhythmicity- autorhythmic 29

30. Conducting System- The heart is AUTORHYTHMIC!!
Cardiac muscle tissue has intrinsic ability to
Generate and conduct impulses
Conducting system
A series of specialized cardiac muscle cells
1. Sinoatrial (SA) node sets the inherent rate of contraction  INTERNODAL PATHWAY
2. Atrioventricular (AV) node
 AV bundle  bundle branches  Purkinje Fibers 30

31. Figure 19.14 The intrinsic conducting system of the heart. (1 of 2)
Superior vena cava
Right atrium 1
The sinoatrial (SA) node (pacemaker) generates impulses.
Internodal pathway
Left atrium 2
The impulses pause (0.1 sec) at the atrioventricular (AV) node.
Subendocardial conducting network (Purkinje fibers) 3
The atrioventricular (AV) bundle connects the atria to the ventricles.
The bundle branches conduct the impulses through the interventricular septum. 4
Inter- ventricular septum 5
The subendocardial conducting network stimulates the contractile cells of both ventricles.

32. Innervation
Heart rate is set by SA node but altered by 2 extrinsic mechanisms….

33. Innervation
Parasympathetic fibers (Cardioinhibitory center in medulla of brain)
Branches of vagus nerve
Decrease heart rate
Restricted to
SA node, AV node, coronary arteries

34. Innervation
Sympathetic nerves (Cardioacceleratory center in medulla of brain)
Travel to heart from cervical and upper thoracic chain ganglia
Innervate SA node, AV node, coronary arteries—as parasympathetic
Also innervate cardiac musculature throughout the heart
Increase heart rate and strength of contraction

35. Figure 19.15 Autonomic innervation of the heart.
Dorsal motor nucleus of vagus
The vagus nerve (parasympathetic) decreases heart rate.
Cardioinhibitory center
Cardioacceleratory center
Medulla oblongata
Sympathetic trunk ganglion
Thoracic spinal cord
Sympathetic trunk
Sympathetic cardiac nerves increase heart rate and force of contraction.
AV node
SA node
Parasympathetic fibers
Sympathetic fibers
Interneurons

36. Circulation to the heart…not by the heart
Circulation to the heart…not by the heart. How does the heart itself get nutrients and oxygen?

37. Blood Supply to the Heart
Coronary arteries
Blood supply to the muscular walls and tissues of the heart
Right coronary artery
Left coronary artery
Arise from base of the aorta and run in the coronary sulcus

38. Blood Supply to the Heart
Left coronary artery (LCA)
Branches into anterior interventricular artery and circumflex artery
Left anterior descending artery (LAD) is the clinical name for anterior interventricular artery

39. Blood Supply to the Heart
Right coronary artery (RCA) descends in coronary sulcus
Branches to form the marginal artery
Later braches into the posterior interventricular artery. Clinically called posterior descending artery (PDA)

40. Carry deoxygenated blood from the heart wall to the right atrium
Cardiac Veins
Carry deoxygenated blood from the heart wall to the right atrium
Coronary sinus—runs in the posterior part of the coronary sulcus
Returns majority of venous blood from the heart to the right atrium
Three tributaries of coronary sinus
Great cardiac vein, middle cardiac vein, small cardiac vein

41. Figure 19.16 Coronary circulation.
Superior vena cava
Aorta
Pulmonary trunk
Anastomosis (junction of vessels)
Left atrium
Left coronary artery
Right atrium
Right coronary artery
Circumflex artery
Left ventricle
Right ventricle
Anterior interventricular artery
Right marginal artery
Posterior interventricular artery
The major coronary arteries
Superior vena cava
Anterior cardiac veins
Great cardiac vein
Coronary sinus
Small cardiac vein
Middle cardiac vein
The major cardiac veins

42. Coronary artery disease
Disorders of the Heart
Coronary artery disease
Atherosclerosis—fatty deposits
Angina pectoris—chest pain
Myocardial infarction—blocked coronary artery
Heart attack
Silent ischemia—no pain or warning

43. Congestive heart failure (CHF)
Disorders of the Heart
Heart failure
Progressive weakening of the heart
Cannot meet the body’s demands for oxygenated blood
Congestive heart failure (CHF)
Heart enlarges
Pumping efficiency declines
Pulmonary arterial hypertension
Enlargement and potential failure of right ventricle

44. Disorders of the Conduction System
Arrythmias—variation from normal heart rhythm
Ventricular fibrillation
Rapid, random firing of electrical impulses in the ventricles
Results from crippled conducting system
Common cause of cardiac arrest

45. Disorders of the Conductory System
Arrythmias (continued)
Atrial fibrillation
Impulses circle within atrial myocardium, stimulating AV node
Promotes formation of clots
Leads to strokes
Occurs in episodes characterized by
Anxiety, fatigue, shortness of breath, palpitations