1. Chapter 11 The Cardiovascular System

2. The Cardiovascular System
A closed system of the heart and blood vessels
-heart pumps blood
-blood vessels - circulate to all parts of body
Deliver oxygens & nutrients and to remove carbon dioxide & waste products

3. The Heart Size of fist In thorax between lungs
Pointed apex toward left hip
Size of fist

4. Figure 18.1a Location of the heart in the mediastinum.
Midsternal line
2nd rib
Sternum
Diaphragm
Point of
maximal
intensity
(PMI)
(a)

5. Heart Coverings & Wall Layers
Pericardium – double serous membrane
Visceral - next to heart
Parietal - outside layer
Serous fluid fills space between the layers
Three layers
1.Epicardium- Outside
visceral pericardium
Connective tissue
2.Myocardium- Middle
Mostly cardiac muscle
3.Endocardium - Inner
Endothelium

7. Figure 18.2 The pericardial layers and layers 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. External Heart Anatomy
Figure 11.2a

9. The Heart: Chambers Right and left act as separate pumps Four chambers
2 Atria - Receiving
- Right atrium
- Left atrium
2 Ventricles - Discharging
- Right ventricle
Left ventricle
Septum - divides the right from left side of the heart.

11. Figure 18.6 Anatomical differences between the right and left ventricles.
Interventricular
septum

12. The Heart: Associated Great Vessels
Aorta - Leaves left ventricle
Pulmonary arteries - Leave right ventricle
Vena cava - Enters right atrium
Pulmonary veins (four) - Enter left atrium

14. The Heart: Valves Allow blood to flow in only one direction
Four valves
2 Atrioventricular valves – between atria & ventricles
Bicuspid valve (left)
Tricuspid valve (right)
2 Semilunar valves - between ventricle & artery
Pulmonary semilunar valve
Aortic semilunar valve
Held in place by chordae tendineae (“heart strings”)

15. Pulmonary valve
Aortic valve
Area of cutaway
Mitral valve
Tricuspid valve
Myocardium
Tricuspid
(right atrioventricular)
valve
Mitral
(left atrioventricular)
valve
Aortic valve
Pulmonary
valve
Fibrous
skeleton
(a)
Anterior

16. Figure 18.8b Heart valves. Myocardium Tricuspid
(right atrioventricular)
valve
Mitral
(left atrioventricular)
valve
Aortic
valve
Pulmonary
valve
Pulmonary valve
Aortic valve
Area of cutaway
(b)
Mitral valve
Tricuspid valve

17. Figure 18.8c Heart valves. Pulmonary valve Aortic valve Area of
cutaway
Mitral
valve
Tricuspid
valve
Chordae tendineae
attached to tricuspid valve flap
Papillary
muscle
(c)

18. Opening of inferior
vena cava
Mitral valve
Chordae
tendineae
Tricuspid valve
Myocardium
of right
ventricle
Myocardium
of left ventricle
Pulmonary
valve
Aortic valve
Area of
cutaway
Papillary
muscles
Mitral valve
Interventricular
septum
Tricuspid
valve
(d)

19. Operation of Heart Valves

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

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

22. Figure 18.10a The semilunar valves.
Aorta
Pulmonary
trunk
As ventricles
contract and
intraventricular
pressure rises,
blood is pushed up
against semilunar
valves, forcing them
open.
(a) Semilunar valves open

23. Figure 18.10b The semilunar valves.
As ventricles relax
and intraventricular
pressure falls, blood
flows back from
arteries, filling the
cusps of semilunar
valves and forcing
them to close.
(b) Semilunar valves closed

24. Pathway of Blood Through the Heart
Right atrium  tricuspid valve  right ventricle
Right ventricle  pulmonary semilunar valve  pulmonary trunk  pulmonary arteries  lungs
PLAY
Animation: Rotatable heart (sectioned)

25. Pathway of Blood Through the Heart
Lungs  pulmonary veins  left atrium
Left atrium  bicuspid valve  left ventricle
Left ventricle  aortic semilunar valve  aorta
Aorta  systemic circulation
PLAY
Animation: Rotatable heart (sectioned)

26. Figure 18.19 Areas of the thoracic surface where the heart sounds can be best detected.
Aortic valve sounds heard
in 2nd intercostal space at
right sternal margin
Pulmonary valve
sounds heard in 2nd
intercostal space at left
sternal margin
Mitral valve sounds
heard over heart apex
(in 5th intercostal space)
in line with middle of
clavicle
Tricuspid valve sounds typically
heard in right sternal margin of
5th intercostal space

27. Mitral Regurgitation
Aortic Stenosis

28. Current Event
Causes of elevated cholesterol levels in our blood and typical medical methods to reduce high cholesterol.  Then focus on if/how hypercholesterolemia can be controlled without the use of drugs.  Be very specific about how it can be done if it is possible.

29. Coronary Circulation Blood in heart doesn’t nourish the heart
Heart’s nourishing circulatory system
Coronary arteries
Come off the aorta
- Cardiac veins
- Blood empties into the right atrium via the coronary sinus

30. Figure 18.7a Coronary circulation.
Aorta
Pulmonary
trunk
Superior
vena cava
Left atrium
Anastomosis
(junction of
vessels)
Left
coronary
artery
Right
atrium
Circumflex
artery
Right
coronary
artery
Left
ventricle
Right
ventricle
Anterior
interventricular
artery
Right
marginal
artery
Posterior
interventricular
artery
(a) The major coronary arteries

31. Figure 18.7b Coronary circulation.
Superior
vena cava
Great
cardiac
vein
Anterior
cardiac
veins
Coronary
sinus
Small cardiac vein
Middle cardiac vein
(b) The major cardiac veins

32. Aorta Coronary Arteries Myocardium
Coronary Circulation Pattern
Aorta
Coronary Arteries
Myocardium
As you must be able to trace the flow of blood through the coronary circulation, indicating the sequential vessels and structures the blood must flow through, we will now go over this. * The pulmonary circulation is a specialized branch of the systemic circulation which circulates blood to and from the heart. As such, it begins with the aorta. * * The first arteries to branch off of the aorta * are the coronary arteries * * which assure an ample supply of highly oxygenated blood, nutrients and hormones to the myocardium. *

33. Coronary Circulation Pattern
Aorta
Coronary Arteries
Myocardium
Cardiac Veins
Coronary Sinus
From the capillaries in the myocardium * the blood flows into the cardiac veins * * which carry blood * to the coronary sinus. * * After collecting blood low in O2 from the cardiac veins, the coronary sinus * introduces the blood into the right atrium * adjacent to where the inferior vena cava enters the right atrium.*
Right Atrium

34. Collateral Circulation
Most organs receive blood from more than one arterial branch.
Arterial anastomosis - where arteries supplying the same area join.
Collateral circulation refers to the situation where most organs have the potential of receiving blood from more than a single arterial branch. * An anastomis is a junction between blood vessels * through which blood can flow directly from one vessel into the other. * An arterial anastamosis is a junction between arteries. * *

35. Myocardial Infarction (MI) Coronary bypass surgery
Embolism
Angina pectoris
Myocardial Infarction (MI)
Coronary bypass surgery
Open Heart Surgery
Coronary artery disease (Adam)
Atherosclerosis

37. Heart Dissection (Lab Manual pg 306)
Heart Dissection I
Heart Dissection II

38. The Heart: Cardiac Cycle
Cardiac cycle – events of one heart beat
Terms: Systole = contraction Diastole = relaxation
Atria contract simultaneously
Atria relax, then ventricles contract

39. Phases of the Cardiac Cycle
Ventricular filling—takes place in mid-to-late diastole
AV valves are open
80% of blood passively flows into ventricles
Atria contract occurs, delivering the remaining 20%

40. Phases of the Cardiac Cycle
Ventricular systole
Atria relax and ventricles begin to contract
Rising ventricular pressure results in closing of AV valves
In ejection phase, ventricular pressure exceeds pressure in the large arteries, forcing the SL valves open

41. Phases of the Cardiac Cycle
Early diastole
Ventricles relax
Backflow of blood in aorta and pulmonary trunk closes SL valves.

42. The Heart: Conduction System
Intrinsic conduction system (nodal system)
Heart muscle cells contract, without nerve impulses, in a regular, continuous way
Sinoatrial node – Pacemaker initiates contraction
Sequential stimulation occurs at other autorhythmic cells
Atrioventricular node
Atrioventricular bundle
Bundle branches
Purkinje fibers

43. Heart rate controlled by its own internal control center
Heart rate controlled by its own internal control center. The SA Node (known as the pacemaker, 75/min) is located in the wall of the right atrium and sends out signals that cause the atria to contract.

44. These signals also travel to the AV Node (50/min) located in the septum between the atria, which relays the signals to the ventricles via the bundle of His (30/min) and Purkinje fibers causing them to contract.
Animation

45. Figure Cardiac intrinsic conduction system and action potential succession during one heartbeat.
Superior vena cava
Right atrium
The sinoatrial
(SA) node
(pacemaker)
generates impulses. 1
Pacemaker potential
Internodal pathway
Left atrium
SA node
The impulses
pause (0.1 s) at the
atrioventricular
(AV) node. 2
Atrial muscle
Purkinje
fibers
The
atrioventricular
(AV) bundle
connects the atria
to the ventricles. 3
AV node
Pacemaker
potential
Ventricular
muscle 4
The bundle branches
conduct the impulses
through the
interventricular septum.
Inter-
ventricular
septum
Plateau
The Purkinje fibers
depolarize the contractile
cells of both ventricles. 5
Milliseconds
(a) Anatomy of the intrinsic conduction system showing the
sequence of electrical excitation
(b) Comparison of action potential shape at
various locations

46. Extrinsic Innervation of the Heart
Heartbeat is modified by the ANS
Cardiac centers are located in the medulla oblongata
Cardioacceleratory center innervates SA and AV nodes, heart muscle, and coronary arteries through sympathetic neurons
Cardioinhibitory center inhibits SA and AV nodes through parasympathetic fibers in the vagus nerves

47. Figure 18.15 Autonomic innervation of the heart.
Dorsal motor nucleus of vagus
The vagus nerve
(parasympathetic)
decreases heart rate.
Cardioinhibitory center
Medulla oblongata
Cardio-
acceleratory
center
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

48. Homeostatic Imbalances
Defects in the intrinsic conduction system may result in
Arrhythmias: irregular heart rhythms
Fibrillation: rapid, irregular contractions; useless for pumping blood

49. Homeostatic Imbalances
Defective SA node may result in
Ectopic focus: abnormal pacemaker takes over
If AV node takes over, there will be a junctional rhythm (40–60 bpm)
Defective AV node may result in
Partial or total heart block
Few or no impulses from SA node reach the ventricles

50. Electrocardiogram A graphic record of the hearts electrical activity.
3 characteristic waves called the P wave, QRS complex, and the T wave.

51. Figure 18.16 An electrocardiogram tracing (lead I).
QRS complex
Sinoatrial
node
Ventricular
depolarization
Ventricular
repolarization
Atrial
depolarization
Atrioventricular
node
S-T
Segment
P-Q
Interval
Q-T
Interval

52. Atrial depolarization, initiated by the SA node, causes the P wave. 1
Figure The sequence of depolarization and repolarization of the heart related to the deflection waves of an ECG tracing.
SA node R
Depolarization
Repolarization R P T P T Q S
Atrial depolarization, initiated
by the SA node, causes the
P wave. 1 Q S 4
Ventricular depolarization
is complete.
AV node R R P T P T Q S
With atrial depolarization
complete, the impulse is
delayed at the AV node. 2 Q S
Ventricular repolarization
begins at apex, causing the
T wave. 5 R R P T P T Q S Q
Ventricular depolarization
begins at apex, causing the
QRS complex. Atrial
repolarization occurs. 3 S
Ventricular repolarization
is complete. 6

53. Figure 18.18 Normal and abnormal ECG tracings.
(a) Normal sinus rhythm.
(b) Junctional rhythm. The SA
node is nonfunctional, P waves
are absent, and heart is paced by
the AV node at beats/min.
(c) Second-degree heart block.
Some P waves are not conducted
through the AV node; hence more
P than QRS waves are seen. In
this tracing, the ratio of P waves
to QRS waves is mostly 2:1.
(d) Ventricular fibrillation. These
chaotic, grossly irregular ECG
deflections are seen in acute
heart attack and electrical shock.

54. Animation

55. Depolarization describes the electrical activity just before contraction.
Repolarization begins just before the relaxation phase.

56. P wave is depolarization of the atria.
QRS complex is depolarization of the ventricles.
T wave is repolarization of the vetricles.
Repolarization of atria is hidden by the QRS complex.

57. The Heart: Cardiac Output
Cardiac output (CO)
Amount of blood pumped by each side of the heart in one minute
CO = (heart rate [HR]) x (stroke volume [SV])
Stroke volume [SV]
Volume of blood pumped by each ventricle in one contraction

58. The Heart: Regulation of Heart Rate
Stroke volume usually remains relatively constant
- Starling’s law of the heart: the more that the cardiac muscle is stretched, the stronger the contraction
Changing heart rate is the most common way to change cardiac output

59. Regulation of Heart Rate
Decreased Heart Rate
1. Parasympathetic nervous system
2. High blood pressure or blood volume
3. Decreased venous return
Increased Heart Rate
1. Sympathetic nervous system
Crisis
Low blood pressure
2. Hormones
Epinephrine
Thyroxine
3. Exercise
4. Decreased blood volume