The Heart

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The Heart

• Size of your fist
• Lies in the centre of the thoracic cavity
• A pump (two pumps actually)
• 4 Chambers
• 4 Valves
• 4 Vessels

2
The Heart

• Diagram Handout
• http//www.neok12.com/diagram/Circulatory-System-0
  1.htm

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5. Deoxygenated blood from the systemic circuit
flows through the vena cava (superior inferior)
into the right atrium.
1. Oxygenated blood from the lungs travels to the
heart via the pulmonary veins and enters the left
atrium.
2. Oxygenated blood flows through the left
atrioventricular valve into the left ventricle.
6. Deoxygenated blood flows through the right
atrioventicular valve into the right ventrical.
3. The muscular left ventricle pumps the
oxygenated blood through the aortic valve into
the aorta.
7. The right ventricle pumps the deoxygenated
blood through the pulmonary valve into the
pulmonary arteries where it travels to the lungs.
4. Oxygenated blood flows to the systemic circuit.
4
Heart Beat

• Lub
• Atrioventricular valves close
• Pressure builds up in the ventricles until the
  pulmonary and aortic valves open
• Blood is pumped into the pulmonary artery and the
  aorta
• Dub
• Pulmonary and aortic valves close
• Atrioventricular valves open and ventricles fill
  with blood

5
Control of heart beat

• Specialized tissue in the right atrium called the
  pacemaker (sinoatrial node)
• Sends an electrical impulse across the heart
• The atria to contract
• The atrioventricular node is stimulated
• Ventricles contract
• Series of electrical impulses maintain a rhythmic
  beat

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Blood Pressure

• The force your heart uses to push blood through
  the blood vessels
• Systolic heart contracts and blood is forced
  through the vessels (higher pressure, 120mmHg)
• Diastolic Heart relaxes (lower pressure, 70mmHg)
• Written as 120/70
• Anything between 110-130 over 70-90 is healthy

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• Schwartzenager
•         http//sciencenetlinks.com/lessons/systems
  -of-the-human-body/
• Heart surgury
•         http//www.abc.net.au/science/lcs/swf/hear
  t.swf
• Heart surgury (less intense)
•         http//www.teachersdomain.org/resource/tdc
  02.sci.life.stru.transplant/

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Blood Flow Through the Heart
5. __________________ blood from the
_______________ ____________ flows through the
___________________ (superior inferior) into
the ______________________
1. _________________ blood from the _______
travels to the heart via the _________ __________
and enters the _____________________
2. __________________ blood flows through the
_________ _____________________ into the
_______________
6. __________________ blood flows through the
_________ ______________________ into the
________________
3. The muscular _____________ ___________ pumps
oxygenated blood through the ____________
______________ into the __________________
7. The ________________________ pumps
deoxygenated blood through the ___________________
_______ into the __________________________ where
it travels to the _____________
4. __________________ blood flows to the
______________________________