1. The Cardiovascular System
A&P Spring 2016

2. Vocabulary Terms Mitral valve Cardiac conduction system Aorta
Aortic valve
Coronary arteries
Cardiac Veins
Coronary Sinus
Systole
Diastole
Cardiac cycle
Functional Syncytium
Cardiac conduction system
Sinoatrial node
Atrioventricular node
A-V bundle
Purkinje fibers
Pericardium
Epicardium
Myocardium
Endocardium
Atria
Ventricles
Septum
Tricuspid Valve
Papillary Muscles
Pulmonary Valve

3. Video Introduction
Get out a sheet of paper and label it Cardiovascular Facts (be sure to put your name too!)
As you watch the video, write down 7 facts to turn in for a grade
Cardiovascular System Intro

4. Structure of the Heart Size and location of the heart
Coverings of the heart
Wall of the heart
Heart chambers and valves
Skeleton of the heart
Path of blood through the heart
Blood supply to the heart

5. Size and location of the heart
Average adult heart is 14cm long and 9cm wide
Located within the mediastinum
Base of the heart lies beneath the 2nd rib

6. Size and location of the heart
Structures that border the heart:
Lungs- laterally
Vertebral column- posteriorly
Sternum- anteriorly

8. Coverings of the heart Pericardium- membrane that encloses the heart
Consists of 3 layers
1. Fibrous pericardium
2. Parietal pericardium
3. Visceral pericardium
( a.k.a. epicardium)

9. Coverings of the heart The pericardial cavity
Space between the parietal and visceral pericardium
Contains serous fluid
Reduces friction between the membranes as the heart moves

11. Wall of the heart Composed of 3 layers 1. outer epicardium
2. middle myocardium
3. Inner endocardium

12. Wall of the heart Outer epicardium
Consists of connective tissue beneath epithelium
Also called the visceral pericardium
Protects the heart by reducing friction

13. Wall of the heart Middle myocardium Consists mostly of cardiac tissue
Muscle fibers are organized in planes
Separated by connective tissue

14. Wall of the heart Inner endocardium
Consists of epithelium and connective tissue
Contains elastic and collagenous fibers
Also contains blood vessels and Purkinje fibers
Purkinje fibers are specialized cardiac muscle fibers

16. Heart Chambers and valves
Heart is divided into 4 hollow chambers
2 upper chambers called atria
2 lower chambers called ventricles
Atria
Receive blood returning to the heart
Ventricles
Contract to force blood out of the heart

18. Test your knowledge! In your notes, answer the following questions:
The base of the heart lies just beneath which rib?
What is another name for the visceral pericardium?
As the heart moves,the serous fluid helps to reduce what?
What are the 4 hollow chambers in the heart?

19. Let's Review What is the pericardium?
How many layers are in the wall of the heart?
Name them
How many chambers are in the heart?

20. Heart chambers and valves
The septum
Wall-like structure that separates the left and right atrium and ventricles
Blood on one side of the heart never mixes with blood on the other side
The atrioventricular (A-V) valve
Ensures one way blood flow between the atria and ventricles
Tricuspid on the right
Mitral on the left

22. Heart chambers and valves
Tricuspid valve
Has 3 tapered projections called cusps
Permits blood to move from right atrium to right ventricle
No backflow
Papillary muscles help keep the cusps from opening in the other direction
Mitral valve
Bicuspid valve
Same function as tricuspid valve

24. Heart chambers and valves
Pulmonary Valve
Located at the base of the pulmonary trunk
Allows blood to leave the right ventricle
Tricuspid
Aortic valve
Located at the base of the aorta
Allows blood to leave the left ventricle
tricuspid

25. Skeleton of the heart Made of dense masses of connective tissue
Provide attachments and support for:
The septum
Heart valves
Muscle fibers

26. Path of blood through the heart
Blood enters the right atrium (deoxygenated)
Blood enters the right ventricle (via heart contraction)
Blood is pushed out of the heart and to the lungs (contraction)
Blood enters the left atrium (oxygenated)
Blood enters the left ventricle (contraction)
Blood is pushed out of the heart and to the body

27. Blood supply to the heart
Coronary Arteries
Branches of the Aorta
Supply oxygenated blood to the tissues of the heart
Cardiac Veins
Branches of the Coronary Sinus
Drain deoxygenated blood from the tissues of the heart

29. Think about it...
What would happen if the structure of the heart was faulty?
Ex, Atrial Septal Defect (ASD)
Atrial Septal Defect
Ex, Valvular Heart Disease
Valvular Heart Disease

30. What's coming up...
Next, we will discuss the actions of the heart

31. The heart actions Cardiac cycle Heart sounds Cardiac conduction system
Electrocardiogram
Regulation of the cardiac cycle

32. Cardiac Cycle This cycle constitutes one complete heart beat
3 basic steps
Terms to know:
Systole- contraction of heart chamber
Diastole- relaxation of heart chamber

33. Cardiac Cycle Step 1 Atria contract (Atrial Systole)
Ventricles relaxed (Ventricular Diastole)
Blood is pushed from atria into the ventricles

34. Cardiac Cycle Step 2 Atria relax (?) Ventricles contract (?)
Blood is pushed from the ventricles into the arteries (out to the body)

35. Cardiac Cycle
Step 3
Atria and ventricles both relax for a brief moment (?)
Atria fill up with blood again

36. Cardiac Cycle Atrial Systole; Ventricular Diastole
Atrial Diastole; Ventricular Systole
Atrial & Ventricular Diastole

37. Heart sounds Lubb- Dubb
Each part of the sound is actually valves in the heart closing
Lubb:
A-V Valves between the atria and ventricles closing
Dubb
Pulmonary and Aortic valves between the ventricles and arteries closing

38. Cardiac Conduction System
Coordinates the events of the cardiac cycle
Composed of specialized cardiac muscle tissue
Sends impulses through the heart

39. Cardiac Conduction System
SA Node
Atrial Syncytium
AV Node
AV Bundle
Pukinje Fibers
Path of impulses through heart

40. Cardiac Conduction System
Sinoatrial (SA) Node
Initiates impulses without stimulation from nerves
Impulses spread to surrounding muscle and cause contraction
Impulse activity is rhythmic
A.K.A. pacemaker

41. Cardiac Conduction System
Atrial Syncytium
Specialized cells in the wall of the heart
Cause atrial chambers to contract when impulse travels through

42. Cardiac Conduction System
Atrioventricular (AV) Node
Serves as a bridge between atria and ventricles
Impulses slow as they pass through

43. Cardiac Conduction System
Atrioventricular (AV) Bundle
A.k.a. Bundle of His
Branches out into ventricle walls

44. Cardiac Conduction System
Purkinje Fibers
Connected to AV bundle branches
Help ventricle walls contract in twisting motion
Push blood into arteries

45. Electrocardiogram “ECG”
Records electrical changes in the myocardium during cardiac cycle
There are several “waves” during one cardiac cycle
P wave
QRS Complex
T wave

46. Electrocardiogram P wave Represents atria contracting QRS Complex
Represents ventricles contracting
Actually 3 waves close together
T wave
Represents chambers beginning to relax

48. Regulation of the Cardiac Cycle
Heart rate changes to fit the body’s needs
Ex. Speeds up when we exercise
Changes in the SA node cause changes in heart rate
b/c it’s the pacemaker

49. Regulation of the Cardiac Cycle
Signals to change heart rate come from the Medulla Oblongata
Contains the “Cardiac Center”
Connected by sympathetic and parasympathetic nerve fibers

50. Regulation of the Cardiac Cycle
Parasympathetic fibers
Release acetylcholine
Tells heart to slow down
Sympathetic fibers
Release Norepinephrine
Tells heart to speed up

51. Regulation of the Cardiac Cycle
Other factors influence heart rate:
Body Temperature
Certain ions
Increased temp = increased rate
Decreased temp = decreased rate

52. Regulation of the Cardiac Cycle
Ions
Calcium
Potassium
Hyperkalemia
Too much potassium
Decreases rate and force of contractions

53. Regulation of the Cardiac Cycle
Hypercalcemia
Too much calcium
Contractions last too long
Hypocalcemia
Not enough calcium
Contraction too short and weak

54. Blood Vessels
Arteries and Arterioles
Capillaries
Venules and Veins

55. Arteries and Arterioles
Vessels that carry blood away from the heart
Subdivide into progressively thinner tubes
Arterioles
Thinner vessels
Branch off from arteries

56. Arteries and Arterioles
Artery Wall
Consists of 3 layers
Innervated by the sympathetic nervous system
Vasoconstricion
vasodilation

57. Arteries and Arterioles
Vasomotor Fibers
Sympathetic nerve fibers
Innervate artery walls
Vasoconstriction
Impulses from fibers causes artery walls to contract
Vasodilation
LACK of impulses causes walls to relax

58. Capillaries Smallest blood vessels Walls composed of only 1 layer
Semipermeable
Openings are thin slits where cells overlap

59. Capillaries Capillaries can form 2 different ways
Direct, single path from arterioles to venules
Creation of highly branched networks
Networks have precapillary sphincters

60. Capillaries Precapillary sphincters
Contracts and relaxes based on needs of surrounding cells
This way blood can flow through different pathways to meet all the needs

61. Capillaries Exchanges in capillaries
Occurs between blood inside and tissue fluid outside
Includes gases, nutrients and metabolic by-products
Exchange methods
Diffusion
Filtration
osmosis

62. Venules and Veins Venules Microscopic vessels
Continue from capillaries
Veins
Larger vessels that return blood to heart
Formed from merged venules

63. Venules and Veins Walls of veins Similar to artery walls
Have flaplike valves
Aid in returning blood to the heart

64. Paths of Circulation
2 paths
Pulmonary Circuit
Systemic Circuit

65. Paths of Circulation Pulmonary Circuit Takes blood through the lungs
4 steps
1. Blood enters right atrium
2. blood enters right ventricle
3. blood is sent to the lungs
4. blood is sent to the left atrium

66. Paths of Circulation Systemic Circuit Takes blood through the body
4 steps
1. blood enters left atrium
2. blood enters left ventricle
3. blood is sent to the body
4. blood is sent to the right atrium

68. Blood Pressure Arterial blood pressure
Factors that influence arterial blood pressure
Heart action
Blood volume
Peripheral resistance
Blood viscosity

69. Blood Pressure
Commonly refers to the force that blood exerts against the inner walls of the arteries

70. Arterial Blood Pressure
Pressure rises and falls as the ventricles contract and relax
Measured in two parts
Systolic pressure
Diastolic pressure

71. Arterial Blood Pressure
Systolic Pressure
Maximum pressure during ventricular contraction
Diastolic Pressure
Minimum pressure during ventricular relaxation

73. Factors that influence- Heart Action
Stroke volume
The volume of blood pushed out of the left ventricle with each contraction
Cardiac Output
Volume pushed out per minute
Calculation = stroke volume X heart rate
Changes in cardiac output can cause changes in blood pressure

74. Factors that influence- Blood Volume
Equals the total amount of blood in the vascular system
Usually about 5 liters for adults
Changes in blood volume can cause changes in pressure

75. Factors that influence- Peripheral Resistance
Force caused by friction between blood and vessel walls
Hinders blood flow
Vessel contraction or dilation can change peripheral resistance
Therefore, changes blood pressure

76. Factors that influence- Blood Viscosity
The ease with which blood flows
Greater viscosity = greater resistance to flowing
Blood pressure increases with greater viscosity
Vice versa