1. Unit 11 Circulatory System The Heart

2. 1. The Heart Hollow, Muscular organ the size of your fist
In the chest between the lungs, slightly left
3 layers of heart wall
Endocardium- smooth epithelial lining
Myocardium- muscle layer
Epicardium/pericardium- outer layer

3. 2. The 4 chambers of the Heart and the 2 Major Valves
Right Atrium(top rt)
Right Ventricle (bottom rt)
Left Atrium ( top left)
Left Ventricle( bottom left)
Tricuspid valve- between RA and RV
Bicuspid(Mitral) valve- between LA and LV

4. BICUSPID/MITRAL VALVE
This valve between the LA and LV is important in dentistry because if you have ever had a severe strept infection that turns into Rheumatic Fever- this valve may be damaged. The cells of this valve are shaped similar to the strept bacteria cells. When your body produces ANTIBODIES to fight this invader, the valve cells are also attacked. That is why a health history asks if you have ever had Rheumatic fever, and if you have- you will need to be on an antibiotic BEFORE any dental treatment is done.

5. VALVES

6. Trace the path of blood through the HEART
Blood enters the RA through the Vena Cava (vein)
From the RA goes through the Tricuspid valve to the RV
Leaves RV via the Pulmonary artery and goes to Lungs to rid of CO2 and pick up O2
Back to LA via the Pulmonary vein
From LA to LV through the Bicuspid valve
Out of LV through the AORTA( major artery)

7. Path of blood summary
Blood enters the heart on top chambers- the ATRIUM
Blood leaves the heart on bottom chambers- VENTRICLES
RT side of heart has blood with wastes
Left side has only clean oxygenated blood
Vena Cava RA
Tricuspid valve RV
Pulmonary artery
Lungs
Pulmonary Vein LA
Bicuspid valve LV
Aorta- to rest of body

8. 3. Blood vessels that serve the heart
2 coronary arteries ( branch off aorta)
Coronary veins empty into coronary sinus that goes to right atrium

9. 4. Describe the Cardiac conductive system
SA nodes- called the PACEMAKER- are in the RA and are fibers that keep the heart beating
AV nodes- in the lower inside corner of the RA stimulate
Purkinje fibers in the Ventricles

10. 5. Cardiac Cycle- 1 complete heartbeat
72 / min
Contraction- blood forced out =SYSTOLIC
Relaxation- heart fills with blood= DIASTOLIC
Lub Dub sound is the valves opening and closing

11. 6. Cardiac Output
Cardiac output is the volume of blood pumped by the left ventrical into the aorta in 1 minute
Depends on needs of the body
Ave 5 liters/minute at rest

12. The Heart 1.

13. THE END