Transcript Heart Structure & Function

16-17 March 2015
What questions do you
have about the heart?
What is the major function of the cardiovascular
system?
• To transport materials (oxygen, nutrients, wastes,
hormones, immune components, heat, etc.) throughout the
body
What is the heart’s role in this system, and what
are the other major components?
• Heart is the pump – supplies the force to move the
blood.
• Blood carries the materials
• Vessels are roads and exchange surfaces
Pericarditis is inflammation of the
pericardium.
Cardiac vessels supply the heart muscle itself with blood.
Heart disease (atherosclerosis) occurs when the aorta or cardiac
arteries become clogged with fatty plaques.
• The right side of the heart
receives oxygen-poor blood from
the body and pumps it to the
lungs
 pulmonary circulation
• The left side of the heart receives
oxygen-rich blood from the lungs
and pumps it to the body
 systemic circulation
Each side has an atrium for
collecting blood and a ventricle
for pumping blood to the lungs
or body
Blood collects in atria while
ventricles contract.
Then, as ventricles relax, atria
contract slightly and ventricles
refill.
Two sides of heart contract and
relax simultaneously.
Use the diagram to determine
the flow of blood through the
heart and body.
Vena cava 
R. atrium 
R. ventricle 
Pulmonary

artery
Pulmonary 
vein
Lung vessels 
L. atrium  L. ventricle 
aorta
Vena cava
 Body vessels 
The walls of the ventricles are
much thicker than that of the
atria? Why?
Ventricles are more
muscular, since they are the
major pumps.
Look at the diagram – how does
the left ventricle differ from the
right? What is the reason for
the difference?
Left ventricle is more muscular
– needs to pump blood
throughout entire body, while
right ventricle just needs to
send blood to lungs.
Atrioventricular valves (tricuspid and mitral)
• hang open when the ventricles are filling
• forced closed when the ventricles contract
• anchored by chordae tendineae
AV valves prevent
backflow from
__________________
to
__________________
Atrioventricular valves (tricuspid and mitral)
• hang open when the ventricles are filling
• forced closed when the ventricles contract
• anchored by chordae tendineae
•
Semilunar valves (pulmonary
and aortic)
•
forced open when
ventricles contract
• closed when ventricles
relax
SL valves prevent backflow from
________ to__________
AV valves prevent
backflow from
ventricles to atria
Atrioventricular valves (tricuspid and mitral)
• hang open when the ventricles are filling
• forced closed when the ventricles contract
• anchored by chordae tendineae
•
Semilunar valves (pulmonary
and aortic)
•
forced open when
ventricles contract
• closed when ventricles
relax
SL valves prevent backflow from
arteries to ventricles
AV valves prevent
backflow from
ventricles to atria
In what stage of the cardiac cycle is the heart shown below?
How do you know?
Ventricles are contracting
(in systole) because SL
valves open (and AV valves
close) when ventricles
contract to force blood only
towards arteries.
Atria are relaxed (in
diastole)
Where else have you heard
these words?
Normal hearts make the sound:
LUB-dup
LUB-dup
LUB-dup
The “LUB” is caused by the closing of the AV valves.
The “dup” is caused by the closing of the semilunar valves.
Heart murmurs are abnormal heart sounds.
• In children, these are often benign.
• In adults, they usually indicate a
problem – often, the failure of the
valves to work properly.
Mitral valve murmur
Aortic stenosis
murmur
Why is it a problem if the valves don’t function properly?
What questions did we answer today?
What haven’t we answered?
What new questions do you have?
HOMEWORK
Wed / Thursday – Present answers to questions
Friday / Monday – Review Exercise 20
Quiz next Wednesday or Friday