Refers to the events of 1 complete heart beat Both atria amp ventricles contract then relax 08 sec if beating 75xmin Key terms to know Diastole relaxation Systole contraction Lubdub ID: 514315
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Slide1
The Cardiac Cycle
Refers to the events of 1 complete heart beat
Both atria & ventricles contract then relax (0.8 sec if beating 75x/min)
Key terms to know
Diastole
- relaxation
Systole
- contraction
Lub-dub
- the sound created by the
closing
of the heart valves (AV and semilunar)Slide2Slide3
Filling Heart Chambers: Cardiac Cycle
Figure 11.7, step 1a
Mid-to-late diastole
(ventricular filling)
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricleSlide4
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricle
Mid-to-late diastole—
blood
flows from the atria into the ventricles (both chambers are relaxed, AV valves open) then the atria contract to squeeze remaining blood into the ventricles Slide5
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular systole
(atria in diastole)
Isovolumetric
contraction phase
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricleSlide6
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular systole
(atria in diastole)
Isovolumetric
contraction phase
Ventricular
ejection phase
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular systole—
blood pressure builds before ventricles contract, when ventricles begin to contract pressure gets high enough opening the semilunar valves allowing blood to be pushed out to the lungs and bodySlide7
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular systole
(atria in diastole)
Early diastole
Isovolumetric
contraction phase
Ventricular
ejection phase
Isovolumetric
relaxation
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricle
Early diastole—
atria finish refilling, when the pressure in the atria exceeds the pressure in the ventricles the AV valves will open allowing blood to fill the ventricles
the cycle begins again Slide8
Murmur- condition in which one of the valves is not functioning properly (could be an AV or semilunar valves) and blood can flow backwards/inefficiently through the heart.Slide9
Which phase of the cardiac cycle does this picture show? How can you be sure?Slide10
Factors that Affect CO
1
.
Venous return (amount of blood that enters the heart)
Inc. venous return inc. stretching
2. How much the ventricle is stretched prior to contraction
Inc. stretching inc. force of contraction
3. High blood pressureSlide11
Factors that Change Heart Rate
Crisis stressors
Electrical system of the heart is more strongly stimulated to beat
inc heart rate
Congestive heart failure
Heart “worn out”
digitalis (drug) prescribed, strengthens contractions to inc. cardiac output
Epinephrine & thyroxine increase heart rate
Electrolyte levels (ions)Low calcium depresses heart; high calcium causes sustained contraction
can cause cardiac arrestLow potassium irregular heartbeatSlide12
Physical Factors that Affect Heart Rate
Age – HR decreases with age (healthy)
Gender – Females > males
Exercise – increases HR
Body temp – higher temp increases HRSlide13
The Cardiac Cycle
Refers to the events of 1 complete heart beat
Both atria & ventricles contract then relax (0.8 sec if beating 75x/min)
Key terms to know
Diastole
- relaxation
Systole
- contraction Lub-dub- the sound created by the closing
of the heart valves (AV and semilunar)Slide14Slide15
Filling Heart Chambers: Cardiac Cycle
Figure 11.7, step 1a
Mid-to-late diastole
(ventricular filling)
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricleSlide16
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricle
Mid-to-late diastole—
blood
flows from the atria into the ventricles (both chambers are relaxed, AV valves open) then the atria contract to squeeze remaining blood into the ventricles Slide17
Why?Slide18
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular systole
(atria in diastole)
Isovolumetric
contraction phase
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricleSlide19
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular systole
(atria in diastole)
Isovolumetric
contraction phase
Ventricular
ejection phase
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular systole—
blood pressure builds before ventricles contract, when ventricles begin to contract pressure gets high enough opening the semilunar valves allowing blood to be pushed out to the lungs and bodySlide20
Filling Heart Chambers: Cardiac Cycle
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Ventricular systole
(atria in diastole)
Early diastole
Isovolumetric
contraction phase
Ventricular
ejection phase
Isovolumetric
relaxation
Ventricular
filling
Left atrium
Right atrium
Left ventricle
Right ventricle
Early diastole—
atria finish refilling, when the pressure in the atria exceeds the pressure in the ventricles the AV valves will open allowing blood to fill the ventricles
the cycle begins again
https://www.youtube.com/watch?v=rguztY8aqpkSlide21
Think about it…
What do you suspect happens to the coronary blood vessels as the heart goes through the cardiac cycle?
What would happen to them during systole?
What would happen to them during diastole?Slide22
Coronary Blood Vessels
Feed the cardiac muscle with oxygen rich blood
The coronary vessels branch off of the base of the aorta
Only fill with blood when the pressure inside of the aorta is low and the blood flows back towards the heart
https://www.youtube.com/watch?v=tBQa8IBzP6I&feature=relatedSlide23
What happens to a heart if it can’t get enough oxygen?
HEART ATTACKSlide24
Why?
https://www.youtube.com/watch?v=eTKICIpShaA&feature=related
http://www.youtube.com/watch?v=DGxS44-rcpsSlide25Slide26
Factors that Affect CO
1
.
Venous return (amount of blood that enters the heart)
Inc. venous return inc. stretching
2. How much the ventricle is stretched prior to contraction
Inc. stretching inc. force of contraction
3. High blood pressureSlide27
Factors that Change Heart Rate
Crisis stressors
Electrical system of the heart is more strongly stimulated to beat
inc heart rate
Congestive heart failure
Heart “worn out”
digitalis (drug) prescribed, strengthens contractions to inc. cardiac output
Epinephrine increase heart rateElectrolyte levels (ions)
Low calcium depresses heart, high calcium can cause sustained contraction leading to cardiac arrestLow potassium causes irregular heartbeatSlide28
Physical Factors that Affect Heart Rate
Age – HR decreases with age (healthy)
Gender – Females > males
Exercise – increases HR
Body temp – higher temp increases HR