1. Thursday April 2nd, 2015 Agenda
“People are capable, at any time in their lives, of doing what they dream of.” – Paulo Coelho
Agenda
Physiology of the heart
Announcements
Turn in blood worksheet 1and 2 if you haven't
If you haven’t taken the Digestive exam this your last week
Cardiovascular exam next Friday

2. Cardiovascular System
Part 3: Physiology Of The Heart

3. The Cardiovascular System
A closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

4. The Heart: Conduction System*
Myocardium of the heart contains cardiac muscle cells
Generate action potentials over and over again in a rhythmic pattern
Intercalated discs allow action potentials to travel from cell rapidly so they function as one cell rather than individual cells
Cardiac cells function as the pacemaker of the heart and set the conduction system
Pacemaker of the heart: sets the rhythm for the entire heart
Conduction system: electrical conduction system that controls the heart rate

5. Cardiac Muscle Tissue
intercalated disc
intercalated disc

6. The Heart: Conduction System *
Cardiac conduction system: The electrical conduction system controls the heart rate
This system creates the electrical impulses and sends them throughout the heart. These impulses make the heart contract and pump blood.
Conduction System Pathway
Sinoatrial Node (SA Node)
Atrioventricular Node (AV Node)
Atrioventricular Bundle (Bundle of His)
Right and Left Bundle Branches
Purkinje Fibers

7. The Heart: components of the conduction system
Sinoatrial Node (SA Node)
Located in the right atrial wall
Establishes the basic rhythm of the heart
Also known as the natural pacemaker
Action potential spontaneously arises in the SA node
Action potential moves through the atria causing both atrium to contract

8. The Heart: components of the conduction system
Atrioventicular Node (AV Node)
Located in the bottom of the right atrium
Cells in the AV Node conduct impulses slowly, so there is a delay as the impulses travels through the node
Allows time for the atria to finish contraction before the ventricles begin contracting

9. The Heart: components of the conduction system
Atrioventicular Bundle (Bundle of His)
Located in the interventricular septum
The action potential is conducted from the atria into the ventricles

10. The Heart: components of the conduction system
Right and Left Bundle Branches
After leaving the Bundle of His the action potential enters the left and right bundle branches
Left and right bundle branches travel through the interventricular septum toward the apex of the heart

11. The Heart: components of the conduction system
Purkinje Fibers
Rapidly conduct the action potential
First to the apex of the ventricles(bottom of the heart)
Then upward to the top of the ventricles
A fraction of a second after the atria contract the ventricles do

12. Check For understanding 4
List the components of the conduction system in the correct order
Act as the pacemaker of the heart, are found in the myocardium and generate action potentials
Electrical system which controls heart rate
Known as the natural pacemaker
Sets the rhythm for the entire heart
Contains cells which slowly conduct an impulse

13. List the components of the conduction system in the correct order
Act as the pacemaker of the heart, are found in the myocardium and generate action potentials
Electrical system which controls heart rate
Known as the natural pacemaker
Sets the rhythm for the entire heart
Contains cells which slowly conduct an impulse
SA Node, AV Node, Atrioventricular Bundle (Bundle of His), Right and Left Bundle Branches, Purkinje Fibers
Cardiac muscle cells
Conduction System
SA node
Pacemaker
AV node

14. The Heart: Cardiac Cycle
Single Cardiac Cycle: all events associated with one heartbeat
2 atria contract while the 2 ventricles relax
then the 2 ventricles contract while the 2 atria relax
Systole: contraction
Diastole: relaxation
Lub-Dub: the monosyllabus describing heart sounds
When the cardiac cycle begins all four chambers are relaxed and the ventricles are partially filled with blood

15. The Heart: Cardiac Cycle Stages*
Atrial Systole
Atria contract
Atrioventricular (AV) valves open
Blood fills the relaxed ventricles
Semilunar valves close

16. The Heart: Cardiac Cycle Stages
Early Ventricular Systole
Atria relax
Ventricles contract causing the AV valves to force close
The Lub sound
Semilunar valves remain closed

17. The Heart: Cardiac Cycle Stages
Late Ventricular Systole
Atria relax
Ventricles contract
AV valves remain closed
Semilunar valves are forced open

18. The Heart: Cardiac Cycle Stages
Early Ventricular Diastole
Atria and ventricles relax
AV valves and Semilunar valves closed
Atria begin passively filling with blood

19. The Heart: Cardiac Cycle Stages
Late Ventricular Diastole
Atria and ventricles relax
Atria passively fill with blood
AV valves open
Semilunar valves closed
The Dub sound

21. Check For understanding 5
All events associated with one heartbeat
The 5 stages of the cardiac cycle
Also known as contraction
Also known as relaxation
Atria relax, ventricles contract, AV valves remain closed, semilunar valves are forced open
Atria and ventricles relax, AV valves and Semilunar valves closed, atria begin passively filling with blood

22. All events associated with one heartbeat
The 5 stages of the cardiac cycle
Also known as contraction
Also known as relaxation
Atria relax, ventricles contract, AV valves remain closed, semilunar valves are forced open
Atria and ventricles relax, AV valves and Semilunar valves closed, atria begin passively filling with blood
Cardiac cycle
Atrial systole, early ventricular systole, late ventricular systole, early ventricular diastole, late ventricular diastole
Systole
Diastole
Late ventricular systole
Early ventricular diastole

23. Tuesday April 7th, 2015 Agenda
“At first glace it may appear too hard. Look again. Always look again”
Fun Fact: If you shout for 8 years, 7 months and 6 days you would produce enough energy to warm a cup of coffee
Announcements
Turn in worksheet 1 on the blood by Friday
Turn in worksheet 2 the anatomy of the heart by Friday
Exam this Friday on the cardiovascular system
Review is posted on Edmodo
Agenda
Finish Physiology of the heart
Work on the review and notecard

24. The Heart: Electrocardiogram
Known as an ECG
Records and displays the electrical events in the heart
Each event has a distinctive waveform

25. The Heart: Electrocardiogram
P Wave
Represents depolarization (contraction) of the atria
Depolarization spreads from SA node towards AV node
Depolarization also spreads from the right atrium to the left atrium

26. The Heart: Electrocardiogram
PR Interval
Measured from the beginning of the P wave to the beginning of the QRS complex
Interval reflects the time the impulse takes to travel from the SA node to the AV node

27. The Heart: Electrocardiogram
QRS Complex
Rapid depolarization (contraction/systole) of the right and left ventricles
Ventricles are larger and stronger than the atria so QRS complex has a larger amplitude than the P wave

28. The Heart: Electrocardiogram
T Wave
Repolarization (relaxation) of the ventricles
QT Interval
Time ventricles depolarize and remain depolarized

29. The Heart: Electrocardiogram
Irregular ECG’s
Tachycardia: fast heart rate
Heart rate of over 100 bpm at rest
Bradycardia: slow heart rate
Heart rate under 60 bpm at rest
Arrhythmia: irregular heartbeat
Fibrillation: condition where the heart is uncoordinated and useless as a pump
Angina Pectoris: chest pain, resulting from ischemia of the myocardium

30. Check For understanding 6
Records and displays the electrical events in the heart
Rapid depolarization(contraction) of the ventricles
Slow heart rate
Depolarization of the atria
Repolarization(relaxation) of the ventricles
Fast heart rate
Irregular heart rate

31. Records and displays the electrical events in the heart
Rapid depolarization(contraction) of the ventricles
Slow heart rate
Depolarization of the atria
Repolarization(relaxation) of the ventricles
Fast heart rate
Irregular heart rate
ECG
QRS complex
Bradycardia
P wave
T wave
Tachycardia
Arrhythmia

32. 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

33. 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

34. The Heart: Regulation of Heart Rate
Increased heart rate
Sympathetic nervous system (fight or flight)
Exercise
Crisis
Hormones
Epinephrine (aka adrenaline)
Thyroxine: produced by the thyroid gland
Decreased blood volume
Makes your heart work harder to pump blood

35. The Heart: Regulation of Heart Rate
Decreased heart rate
Parasympathetic nervous system
More oxygen in blood during rest so heart doesn’t have to work hard to pump blood
High blood pressure or blood volume
More blood flowing through the body so the heart doesn’t have to work hard to pump

36. Friday April 10th , 2015 You have till 12:42 to study
After the exam turn in Worksheet 1 on the blood and Worksheet 2 on the anatomy of the heart if you haven’t turned them in yet
After the exam turn in your notecard for extra credit
Remember bring 2 liter bottles for extra credit till next Friday, each bottle is worth 5 pts