1. Cardiovascular System

2.  Heart Actions
Cardiac cycle-heart beat
Atria contract together
Ventricles contract together
Atrial systole-atria contract
Diastole-relaxation of heart
Ventricular systole-ventricles

3. Cardiac Cycle Steps High pressure in atria
Pressure down in ventricles; build in atria
High pressure in ventricles

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5. Relaxation-no muscle contraction/no pull on chordae tendinae
Atrioventricular valves open and close HOW?
Contract
Papillary muscles contract
Pull on chordae tendinae
Valves close!
Papillary muscles contract due to stimulation from purkinje fibers
Relaxation-no muscle contraction/no pull on chordae tendinae
Valves

6. Heart Sounds
Open and close of valves
Lubb-ventricular contraction, AV valves closing
Dupp-ventricles relax, pulmonary and aortic valves close
Heart murmur-cusps not close enough and cause blood leak

7. Impulse goes to atrial syncytium (mass of merging cells)
Cardiac Conduction System
Impulse travels through myocardium (middle layer of heart)
SA node-pacemaker
Posterior right atrium
Creates impulse for heart beat
Sends impulse times per minute
Impulse goes to atrial syncytium (mass of merging cells)
Left and right atrium contract

8. Signal conduction continued
Impulse travels through junctional fibers
Slows signal down so atria can contract completely and empty of blood before the impulse goes down to the ventricles
Goes to AV (atrioventricular node)
Located in septum
Goes to AV bundle (bundle of His)
Branch into purkinje fibers
Make connection with papillary muscles
Action squeezes blood out of ventricles

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F. Electrocardiogram
a recording of the electrical changes that occur during a cardiac cycle.
P wave,
depolarization (contraction) of the atria.
QRS complex
depolarization of ventricles (contraction) and hides the repolarization (relaxation) of atria.

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T waves
end the ECG pattern
ventricular repolarization (relaxation)

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16. 1. Atria begin depolarize 2. Atria depolarize. 3
1. Atria begin depolarize 2. Atria depolarize. 3. Ventricles depolarize at apex; atria repolarize 4. Ventricles depolarize 5. Ventricles begin repolarization at apex. 6. Ventricles repolarize.

17. How to read one?

18. Diagnostic Value of ECG
Abnormalities in conduction pathway
Myocardial infarction (heart attack)
Heart enlargement
Electrolyte and hormone imbalance
Ischemia-blood supply restriction

21. Fast heart; chest pain,
Shortness of breath, abnormal pacemaker
Heart rate is less than 60 beats

22. Blood pressure Refers to pressure in arteries
Systolic (pressure in arteries when ventricles contract) over diastolic (pressure in arteries when ventricles are filling up with blood) pressure
120/80 is normal
Pulse (normal is 60 to 100 beats)-expanding and recoiling of arteries
Many factors influence blood pressure

23. Heart Action
This determines how much blood enters the arterial system when the ventricles contract
Stroke volume-volume of blood leaving LV
About 70 ml in average male
Cardiac output-volume per minute
Stroke volume x heart rate
Cardiac output, blood pressure, and stroke volume directly related

24. Blood volume-Factor that influences this
Sum of formed elements and plasma volumes in the vascular system
Blood pressure is directly proportional to blood volume
Can change due to dehydration (bp drops), blood transfusion, hemorrhage (bp drops)

25. Control of Blood Pressure
Autonomic nervous system responses
Peripheral resistance
Pressure between blood and vessel walls
Temperature change
Higher temp, higher blood pressure

26. Baroreceptors Located in aortic arch
Arterial blood increases, basoreceptors send nerve impulse to medulla oblongata
Sends impulse to SA node
Cause heart rate to decrease
Blood pressure return to normal
Arterial blood decreases, sends signal to SA node to increase heart work
Exercise, rise in temp, emotions

27. Hypertension Hypertension-high blood pressure in arteries
Caused by kidney disease, high sodium intake, obesity, stress, arteriosclerosis
Lead to enlarged heart due to increase pumping action of LV
Cause embolism, thrombosis, stroke

28. Vein Control Skeletal muscles-pushes blood to the heart
Breathing movements
Vasoconstriction-low pressure causes muscles to contract

29. Sheep Heart Dissection