Topic 2.2: Cardiovascular System Flashcards
2.2.1 State the composition of blood
- Erythrocytes (red blood cell) = 45%
- Plasma = 55%
- Leukocytes (white blood cell) + Platelets = <1%
2.2.2. Distinguish between the functions of erythrocytes, leukocytes and platelets
- Erythrocytes - transport oxygen using hemoglobin
- Leukocytes - immune system, protects body against infection and foreign invaders
- Platelets - blood clotting, prevent blood clot
2.2.3. Describe the anatomy of the heart with reference to the heart chambers, valves and major blood vessels.
4 chambers:
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle
4 valves:
- Bicuspid valve
- Tricuspid valve
- Aortic valve
- Pulmonary valve
4 major blood vessel:
- Vena cava (superior + inferior)
- Pulmonary vein
- The aorta
- Pulmonary artery
2.2.5. Outline the relationship between the pulmonary and systemic circulation.
PULMONARY CIRCULATION:
- Deoxygenated blood (right side of heart) → lung → oxygenated → left side
SYSTEMIC CIRCULATION:
- Oxygenated blood (left side of heart) → body → deoxygenated → right side
Pulmonary Circulation pathway
Systemic Circulation Pathway
2.2.4. Describe the intrinsic and extrinsic regulation of heart rate and the sequence of excitation of the heart muscle. (important)
- SA node fires causing 2 atria to contract
- Slight delay in stimulation of the AV node which gives ventricle time to fill blood
- Signal from AV node through the AV Bundle (Bundle of His) and then Purkinje fibers into myucardium causing contraction of the ventricles.
- Begins at the apex and progresses upwards causing blood to be pushed upward
2.2.6. Describe the relationship between heart rate, cardiac output and stroke volume at rest and during exercise.
Cardiac Output = Heart Rate x Stroke Volume
During exercise:
- CO increases. This happens with increases in HR and SV. SV has the most dramatic effect on CO during exercise.
At rest:
- CO remains constant. HR and SV remain stable.
In general, People with higher resting SV have lower resting HR.
More blood per contraction means fewer heartbeats are needed.
Analyse cardiac output, stroke volume and heart rate data for different age at rest and during exercise.
Young:
- Lower stroke volume
- Higher resting and working heart rate to maintain cardiac output
- Approx. 210bpm
Old:
- SV ↑, HR ↓ as we age
- CO ↓ because SV & HR ↓
- Has lower max heart rate than young
2.2.8. Explain cardiovascular drift
Increased body temperature lowers venous return, reduces stroke volume, and raises heart rate to maintain cardiac output.
2.2.9. Define the terms systolic and diastolic blood pressure.
Systolic - force exerted by blood on arterial walls during ventricular contraction
Diastolic - force exerted by blood on arterial walls during ventricular relaxation
2.2.10. Analyse systolic and diastolic blood pressure data at rest and during exercise.
At rest:
- Systolic > Diastolic
During exercise:
- Systolic > Diastolic
2.2.11. Discuss how systolic and diastolic blood pressure respond to dynamic and static exercise.
Dynamic:
- Increase blood flow → increase systolic → then levels off
- Diastolic remains relatively the same
Static:
- Increase in blood pressure (systolic & diastolic) bc sustained muscular force compress arteries → increasing resistance to blood flow
2.2.12. Compare the distribution of blood at rest and the redistribution of blood during exercise.
At rest:
- Blood is distributed more evenly
- Less blood is distributed at a slower rate
- Skin will have minimal blood flow depending on the climate
During exercise:
- More blood is distributed at a faster rate.
- Active muscles can demand as much as 90% of the total blood flow.
- More capillaries open to meet muscle demand.
- Organs receive much less blood than active muscles. But essential organs like brain and heart are protected with adequate blood flow.
- Skin receives significant blood flow to regulate body temperature.
2.2.13. Describe the cardiovascular adaptations resulting from endurance exercise training.
- Increased left ventricular volume
- More capillaries are present
- Lower resting heart rate
- Increase arterio-venous oxygen difference
- Increase blood volume and plasma
2.2.14. Explain maximal oxygen consumption (VO2 max)
Maximal rate and use of oxygen consumption during exercise measured in ml/kg/1min (VO2max)
2.2.15. Discuss the variability of maximal oxygen consumption in selected groups.
(Trained vs Untrained)
Trained > Untrained
Trained individuals:
- Higher VO2max levels.
- Trained athletes are able to demonstrate their full cardio-respiratory potential
Untrained:
- Obtain fatigued muscles and are only able to reach sub-maximal levels.
2.2.16. Discuss the variability of maximal oxygen consumption with different modes of exercise. (important !!)
- Running > cycling > arm ergometer test
- Due to amount of muscle mass used, in relation to oxygen consumption
- More muscle used = more maximal oxygen consumption
- Less muscle used = less maximal consumption
Define Cardiac Output
The volume of blood pumped from heart/ventricle in one minute
Define Stroke Volume
The volume of blood pumped from the heart/left ventricle in one beat
What effect does Strenuous exercise have on CO?
Strenuous exercise can increase CO to 21L/min in a fit person and 35L/min in world-class athletes.
Name the two branches of the autonomic nervous system?
- Sympathetic (fight, flight, freeze)
- Parasympathetic (rest & digest)
Analyse cardiac output, stroke volume and heart rate data for different gender at rest and during exercise.
- Women generally have lower stroke volume due to size
- Has smaller blood volume
- Higher resting and sub max heart rate
Analyse cardiac output, stroke volume and heart rate data for different training level at rest and during exercise.
Trained:
- Aerobic training = ↓resting HR and ↑SV.
- At sub-max, stable cardiac output reduces heart workload = higher SV + lower HR.
- Max cardiac output rises with training as ↑SV; max HR stays constant.
- SV at all state (rest, sub max, max) > untrained
Untrained:
- HR during rest, sub max and max > trained
- CO stays relatively the same but during max. training is way lower
