Transcript Lesson 6 Circulatory System

Unit 11 Circulatory System
The Heart
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/pericardiu
m- outer layer
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 valvebetween RA and RV
• Bicuspid(Mitral) valvebetween LA and LV
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 Feverthis 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 haveyou will need to be on an antibiotic BEFORE any
dental treatment is done.
VALVES
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)
Path of blood summary
• Blood enters the heart on
top chambers- the
ATRIUM
• Blood leaves the heart on
bottom chambersVENTRICLES
• RT side of heart has
blood with wastes
• Left side has only clean
oxygenated blood
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Vena Cava
RA
Tricuspid valve
RV
Pulmonary artery
Lungs
Pulmonary Vein
LA
Bicuspid valve
LV
Aorta- to rest of body
3. Blood vessels that serve the
heart
• 2 coronary arteries ( branch off aorta)
• Coronary veins empty into coronary sinus
that goes to right atrium
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
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
6. Cardiac Output
• Cardiac output is the
• Ave 5 liters/minute at
volume of blood
rest
pumped by the left
ventrical into the aorta
in 1 minute
• Depends on needs of
the body
The Heart
1.
THE END