1. CARDIOVASCULAR SYSTEM
Replacing hearts - nova
CARDIOVASCULAR SYSTEM

2. Cardiovascular System Functions
The cardiovascular system allows exchange of oxygen and carbon dioxide between blood and tissues
Accomplished by three components:
Heart – pump blood
Vessels – transport network; arteries, veins and capillaries
Blood – transports dissolved gases, nutrients, hormones and metabolic wastes
Our body cells rely on the surrounding interstitial fluid for oxygen, nutrients and waste disposal. Conditions in the interstitial fluid are kept stable through continuous exchange between the peripheral tissues and circulating blood.

3. Organization of Cardiovascular System
A closed system with two circuits
Systemic Circuit – oxygenated blood leaves the heart through the aorta and returns to the heart through systemic veins
Pulmonary Circuit– deoxygenated blood leaves the heart through pulmonary arteries and returns to the heart through pulmonary veins

4. The Heart…size, shape and location
Muscular organ composed of cardiac muscle
About the size of a closed fist
Weighs less than a pound
Located within the thoracic cavity
Flanked on either side by the lungs
At rest, the average adult heartbeat is 72 beats per minutes. This is equal to 100,000 beats per day. 2 ounces of blood is pumped each minute which means 75 gallons of blood are pumped in one hour.

5. The heart…coverings and wall
Pericardium = double walled sac around the heart
Protects the heart and anchors it to surrounding structures
Produces a lubricating fluid to create a frictionless environment
Pericarditis = inflammation of the pericardium

6. The heart…coverings and wall
The wall of the heart is composed of three layers:
Epicardium = continuous with the pericardium
Myocardium = thick bundles of cardiac muscle; the contractile part of the heart
Endocardium = think sheet of endothelium that lines the heart chambers

7. The heart…coverings and wall

8. Anatomy of the heart 4 chambers
Upper chambers = atria = receiving chambers
Lower chambers = ventricles = pumping chambers
Left ventricle forms the apex or point of the heart
Interventricular septum divides ventricles

9. Chambers – Anterior View
Left atrium
Right atrium
Right Ventricle
Left Ventricle

10. Chambers – Posterior View
Left atrium
Right atrium
Right Ventricle
Left Ventricle

11. Chambers – Internal View
Left atrium
Right atrium
Left Ventricle
Right Ventricle

12. Right Atrium Tricuspid
Anatomy of the heart
Heart Valves permit flow of blood in one direction
1. AV valves divide atria and ventricles; prevent backflow of blood into atria when ventricles contract
Bicuspid valve (mitral valve) – between left atria and left ventricle
Tricupsid valve between right atria and right ventricle
Chordae Tendinae = tiny white cords that anchor the valves to the walls of the ventricle
When the heart is relaxed and the atria are filling, the AV flap hang open into the ventricle. As the ventricles contract, the pressure within the ventricle increases which forces the AV flaps upward. The chordae tendinae at this point are keeping the flaps from blowing upward into the atria.
LAB RAT…
Left Atrium Bicuspid
Right Atrium Tricuspid

13. AV Valves

14. Anatomy of the heart
Heart Valves permit flow of blood in one direction
2. Semilunar valves guard the large vessels leaving the ventricles; prevents arterial blood from falling back into the ventricles
Pulmonary semilunar valve
Aortic semilunar valve

15. Semilunar Valves

16. Each set of valves operates at a different time in a contraction cycle
Each set of valves operates at a different time in a contraction cycle. The AV valves are open during relaxation and are forced closed when the ventricles contract. The semilunar valves are closed during relaxation and forced open during contractions. The valves open and close in response to pressure changes

17. Anatomy of the heart Great Vessels of the Heart
Superior and inferior vena cava – take deoxygenated blood from the body to the right atrium
Pulmonary trunk gives rise to Pulmonary arteries (left and right) – take deoxygenated blood from right ventricle to lungs for oxygen
Pulmonary veins (left and right) – takes oxygenated blood from lungs to left atrium
Aorta – takes blood away from left ventricle to rest of body

18. Anatomy of the heart Cardiac Circulation
Coronary arteries branch from the base of the aorta and encircle the heart at the junction between the atria and ventricles
Compressed when ventricles are contracting and fill when the ventricles are relaxed
Cardiac veins drain the myocardium into the right atrium
Although the heart is bathed in blood, The blood that is contained within the heart isn’t given enough time to supply the myocardium with nutrients so the heart has its own blood supply called the cardiac arteries.

19. Vessels – Anterior View
aorta
L. Pulmonary artery
Superior vena cava
Pulmonary trunk
R. Pulmonary artery
R. Pulmonary
veins
L. Pulmonary
veins
Coronary vessels
Inferior vena cava

20. Vessels – posterior view
Superior vena cava
aorta
R. Pulmonary artery
L. Pulmonary artery
R. Pulmonary veins
L. Pulmonary
veins
Inferior vena cava
Coronary vessels

21. When the heart beats The Right side of the heart
Deoxygenated blood flows into heart from vena cava
Right atrium
Tricuspid valve
Right ventricle
Pulmonary semilunar valve
Pulmonary artery
Lungs (to pick up oxygen)

22. What’s behind a heartbeat
The Left side of the heart
Oxygenated blood flows into heart from lungs via pulmonary veins
Left atrium
Bicuspid valve (aka mitral valve)
Left ventricle
Aortic semilunar valve
Aorta
Body (to deliver oxygen)

23. Control of Heart Contraction
General info about cardiac muscle
Cardiac muscle cells contract spontaneously and independently, even if all nervous connections are cut
Muscle cells in different areas of the heart have different rythms
Atria cells contract at a faster rate than ventricular cells
An intrinsic control system regulates activity

24. Intrinsic Control System
Intrinsic conduction system
Sinoatrial node (SA node)
Atrioventricular node (AV node)
Bundle of His
Purkinje Fibers

25. Sinoatrial Node (SA node)
The pacemaker of the heart
Located in right atrium
SA node sends out electrical impulse
Impulse spreads over atria, making them contract
Impulse travels to AV node

26. Atrioventricular node (AV node)
Conducting cell group between atria and ventricle
Carries impulse to bundle of His

27. Bundle of His
Conducting fibers in septum (divider between left and right sides of the heart
Divides into right and left branches to a network of b ranches in ventricles (Purkinje Fibers)

28. Purkinje Fibers
Impulse shoots along Purkinje fibers causing ventricles to contract

29. Electrocardiogram (EKG or ECG)
Device used to record the electrical activity of the heart
Systole = contraction phase
Diastole = relaxation phase
Baseline of EKG is flatline
P = atrial contraction
QRS = ventricular contraction
T = ventricular relaxation