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.
- 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:
- Stroke volume increase, heart rate decrease as we age
- Decrease cardiac output because decrease in both heart rate and stroke volume
- 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 of the capillary network will open to supply muscles with increased 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.
- Highest values in running, then cycling, lowest on arm ergometer test
- Cross-country skiers > runners (more oxygen demand on the upper-body)
- Oxygen consumption is less with arm crank (arm ergometry) than cycle ergometry.
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 lowers resting heart rate and increases stroke volume.
- At sub-max, stable cardiac output reduces heart workload via higher stroke volume and lower heart rate.
- Max cardiac output rises with training as stroke volume increases; max heart rate stays constant.
- Higher stroke volume at all state (rest, sub max, max) than untrained
Untrained:
- Heart rate during rest, sub max and max are all higher than trained
- Cardiac output stays relatively the same but during max. training is way lower
How does training increase VO2 max?
- Increase in stroke volume
- Increased number of capillaries
How does the autonomic nervous system speed up or slow down the heart?
Sympathetic:
- Releases epinephrine which increases SA node firing (increase in HR).
Parasympathetic:
- Releases acetylcholine which slows the SA node firing (decrease in HR).
Explain Absolute VO2 max vs Relative VO2 max
- Absolute VO2 Max: Does NOT account for differences in size and mass. Expressed in L/min
- Relative VO2 Max: Does account for differences in size and mass. Expressed in ml/kg/min
What is the Fick Equation?
VO2 max = Max CO x Max (a-v)O2
What is “Max (a-v)O2”
Indication of how much oxygen has been removed by the capillaries and used by the body
What are the two nodes in heart?
- Sinoatrial node - send impulse
- Atrioventricular node
Which valve is located between the right atrium and the right ventricle?
A. Bicuspid valve
B. Pulmonary valve
C. Tricuspid valve
D. Aortic valve
C.
Tricuspid valve
Which valve is located between the left atrium and the left ventricle?
A. Bicuspid valve
B. Pulmonary valve
C. Tricuspid valve
D. Aortic valve
A.
Bicuspid valve
What is affected by training more HR or SV?
- Max HR remains the same, however with training one can tolerate a higher HR for longer.
- SV increases most with training due to left ventricle growth, result in a higher SV, thus more CO
Factors that affect VO2 max
- Heredity
- Age
- Gender
- Body size and composition
- Mode of exercise
- Types of muscle fibers used during the exercise
- Altitude
- Temperature
- Training status
2.2.15. Discuss the variability of maximal oxygen consumption in selected groups. (Male vs Female)
Why is there a significant difference in VO2 max between males and females?
- Differences in body composition
- Hemoglobin concentration (males have slightly more hemoglobin than females)
2.2.15. Discuss the variability of maximal oxygen consumption in selected groups. (Age)
- Children have much lower absolute VO2 max but when adjusted for body mass it is very similar to adults.
- VO2 max typically declines about 1% per year from age 20-25
- Reflects a gradual decline in max HR that can be achieved
2.2.15. Discuss the variability of maximal oxygen consumption in selected groups. (Athlete vs Non-Athlete)
Athlete > Non-Athlete
Athletes have better endurance:
- Need less oxygen pumped to the muscles
- Allowing them to exercise for a longer period of time without getting as tired
Chemoreceptors
- send information to the cardiac centre
- detect changes in blood level, co2 and oxygen
Baroreceptors – Blood Pressure Receptors
- detect drops in blood pressure
- send impulse to cardiac center
- increasing firing rate of SA node
Proprioreceptors
provide information about joint angle, muscle length, and muscle tension
