I. Components of the cardiovascular system and their structure and function
A. The heart (Visit The Heart: An Online Exploration.)1. Size and weight
Key Point: The heart is small relative to its functional role.
Key Point: The size and weight of a woman’s and a man’s heart differ.
2. Muscular pump (Visit Human Anatomy On-Line—Heart.)
Key Point: The heart is capable of beating independently without extrinsic control (i.e., nervous or endocrine stimulation).
3. Four chambers of the heart
Key Point: The anatomical differences between the atria and ventricles and between the right and left ventricles are functionally significant.
4. Unidirectional heart valves5. Cardiac wall structure
a) Endocardiumb) Myocardium
c) Epicardium
6. Myocardial tissue structure
Key Point: The branching fibers and intercalated discs have functional significance.
Key Point: The striated appearance of the heart has a structural basis.
7. Conduction systema) Sinoatrial (SA) nodeb) Atrioventricular (AV) node
c) AV bundle (bundle of His)
d) Bundle branches
e) Purkinje fibers
B. Essentials of cardiac function
1. Blood flow through the chambers of the heart2. Pulmonary and systemic circulations
3. Coronary circulation
Key Point: The myocardium receives its oxygen and nutrient supply from the coronary arteries and not from the blood flowing through the chambers of the heart. An understanding of this fact helps to explain why blockage of a coronary artery can lead to myocardial infarction.
4. Electrocardiographic monitoring of cardiac activitya) Components of the electrocardiogram (Visit the Alan E. Lindsay ECG Learning Center.)b) Arrythmias
Key Point: The electrocardiogram represents the electrical activity of the heart. It is not a direct reflection of its contractile activity.
5. Events of the cardiac cyclea) Opening and closing of the heart valvesb) Ventricular volume and pressure changes
c) Heart sounds
6. Cardiac volumes
a) End-diastolic volumeb) End-systolic volume
c) Stroke volume (SV)
d) Ejection fraction
e) Cardiac output
Key Point: Cardiac output in women differs from that in men.
C. The vascular system1. Arteries2. Arterioles
3. Capillaries
4. Venules
5. Veins
Key Point: Arteries always carry blood away from the heart; veins always carry blood back to the heart. In other words, classification depends on direction of blood flow.
D. Blood1. Functionsa) Gas, nutrient, and waste transportb) Temperature regulation
c) Acid-base balance
2. Volume
Key Point: The volume of blood in women differs from the volume in men.
3. Composition4. Hematocrit
Key Point: The hematocrit in women differs from that in men. Hematocrit is an indirect indication of the oxygen-carrying capacity of the blood.
5. Hemoglobin
Key Point: Discuss the role of hemoglobin in oxygen transport.
E. Circulatory function1. Mean arterial pressure2. Total peripheral resistance
Key Point: Overall blood flow is determined by the balance between mean arterial pressure and total peripheral resistance, and it is closely matched to overall metabolic demands.
3. Distribution of blood flowa) Primarily through arteriolar dilation and constrictionb) Mechanisms that control distribution
(1) Autoregulation(2) Neural control
Key Point: Distribution of blood flow is matched closely to localized metabolic demands. (Visit Human Anatomy On-Line—Cardiovascular System.)
4. Venous return of blood to the hearta) Muscle pumpb) Venous valves
c) Respiratory pump
Key Point: The volume capacity of venous circulation is large relative to arterial circulation.
II. Cardiovascular response to acute exercise
A. Heart rate1. Resting heart rate
Key Point: The resting heart rate of women differs from that of men. Factors other than sex can affect resting heart rate.
2. Increase in heart rate during acute exercisea) Relationship of exercise intensity to oxygen consumptionb) Estimation of maximal heart rate (HRmax)
Key Point: Estimating an individual’s HRmax with the following equation has both advantages and limitations: HRmax = 220 – age.
3. Steady-state heart rateB. SV
1. Determinants of SVa) Venous return (preload)b) Ventricular distensibility
c) Ventricular contractility
d) Aortic pressure (afterload)
2. Resting SV
Key Point: Resting SV in women differs from that in men.
3. Increase in SV during acute exercisea) Influence of body positionb) Possible influence of training status
c) Possible influence of exercise modality
4. Mechanisms of SV increase due to acute exercise
a) Frank-Starling mechanismb) Increased cardiac contractility
C. Cardiac output
1. Resting cardiac output
Key Point: Illustrate resting cardiac output using five 1-L bottles.
2. Increase in cardiac output during acute exercisea) Relationship to exercise intensityb) Contributions of heart rate and SV increases
Key Point: To illustrate the contributions of heart rate and SV increases, use the following equation: Cardiac output = heart rate × SV. In addition, use 1- or 2-L bottles or use 1-gallon jugs to illustrate this point.
c) Influence of exercise modalityD. Blood flow
1. Distribution of blood flow (cardiac output) at rest2. Changes in blood flow distribution during acute exercise
3. Effects of heavy environmental heat load and of prolonged exercise
a) Increased blood flow to the skinb) Blood flow reduction due to sweating and fluid shift from blood to tissues
c) Reduced availability of blood to working muscles
d) Cardiovascular drift
E. Blood pressure
1. Resting blood pressure
Key Point: Emphasize that 120/80 is not to be considered as an absolute when determining "normal" blood pressure.
2. Effects of different types of exercise on blood pressurea) Steady-state endurance exerciseb) Resistance exercise
c) Incremental exercise
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