1. Cardiovascular Circuits & Heart Physiology
11b

2. How does blood flow through the heart and body?

3. Blood Flow Through the Heart & Body
Pulmonary Circulation
Blood flow through lungs
Systemic Circulation
Blood flow through body
Coronary Circulation
Blood flow through heart

4. Pulmonary Circulation
Occurs in Lungs
FUNCTION
Add Oxygen to blood, remove Carbon Dioxide from blood
Process
Oxygen Poor blood leaves Right Ventricle through Pulmonary Arteries
Oxygen Poor blood flows through lungs and becomes Oxygen Rich
Oxygen Rich blood leaves lungs and enters Left Atrium through the Pulmonary Veins

6. Systemic Circulation Occurs in Body FUNCTION Process
To deliver oxygen and nutrients to body cells and remove carbon dioxide and waste from cells
Process
Oxygen Rich blood leaves Left Ventricle through Aorta
Oxygen Rich blood is delivered to cells all over the body and becomes oxygen poor
Oxygen Poor blood enters the Right Atrium through the Superior and Inferor Vena Cava

8. Blood Flow through heart animation

9. How are the tissues and cells of the heart nourished
How are the tissues and cells of the heart nourished? Don’t they need a lot of oxygen and nutrients?

10. Coronary Circulation FUNCTION: Process: Coronary arteries
Nourish Heart cells
Process:
Coronary arteries
Deliver Oxygen rich blood from the Aorta to heart cells
Cardiac veins
Oxygen Poor blood empties into the Right Atrium via the coronary sinus
Slide 11.12
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11. Coronary Circulation

12. Quick Quiz Describe what happens in Pulmonary Circulation
What is the purpose of Systemic Circulation?
How are the heart tissues and cells nourished?

13. So, the heart pumps blood…how does it know when to pump?

14. The Heart: A hard working organ
Your heart beats continuously
Circulates your entire blood volume 1000 times in one day
Pumps the equivalent of 6000 quarts in one day!

15. The Heart: Conduction System
Intrinsic conduction system (nodal system)
Heart muscle cells contract, without nerve impulses, in a regular, continuous way
This means your heart can beat even if your brain is not working!
Slide 11.13a
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16. The Heart: Conduction System
Special tissue sets the pace
Sinoatrial node
Pacemaker
Atrioventricular node
Atrioventricular bundle
Bundle branches
Purkinje fibers
Slide 11.13b
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17. Heart Contractions Contraction is initiated by the sinoatrial node
Sequential stimulation occurs at other autorhythmic cells
Slide 11.14a
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18. Heart Contractions Slide 11.14b Figure 11.5
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19. Quick Quiz What part of the heart initiates contraction?
What does the Atrioventricular Node do?

20. The Heart: Cardiac Cycle
Atria contract simultaneously
Atria relax, then ventricles contract
Systole = contraction of ventricles
Diastole = relaxation of ventricles
Slide 11.16
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

21. The Heart: Cardiac Cycle
Cardiac cycle – events of one complete heart beat
Mid-to-late diastole – blood flows into ventricles
Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood
Early diastole – atria finish re-filling, ventricular pressure is low
Slide 11.17
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

22. Filling of Heart Chambers – the Cardiac Cycle
Figure 11.6
Slide 11.15
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23. Quick Quiz What is Systole? What is Diastole?
Why do you think we measure heart contractions when the Ventricles contract?

24. The Heart: Cardiac Output
Cardiac output (CO)
Amount of blood pumped by each side of the heart in one minute
CO = (heart rate [HR]) x (stroke volume [SV])
Stroke volume
Volume of blood pumped by each ventricle in one contraction
Slide 11.18
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

25. The Heart: Regulation of Heart Rate
Stroke volume usually remains relatively constant
Starling’s law of the heart – the more that the cardiac muscle is stretched, the stronger the contraction
Changing heart rate is the most common way to change cardiac output
Slide 11.20
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26. The Heart: Regulation of Heart Rate
Increased heart rate
Sympathetic nervous system
Crisis
Low blood pressure
Hormones
Epinephrine
Thyroxine
Exercise
Decreased blood volume
Slide 11.21
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27. The Heart: Regulation of Heart Rate
Decreased heart rate
Parasympathetic nervous system
High blood pressure or blood volume
Dereased venous return
Slide 11.22
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28. Cardiac Output Regulation
Figure 11.7
Slide 11.19
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29. Quick Quiz What is Cardiac Output?
Name 2 things that increase heart rate
Name 2 things that decrease heart rate