LEC13: Cardiovascular System (Age-Related Changes in Physiology and the Effects of Exercise) Flashcards
What are the three components to the cardiovascular system?
- Heart
- Blood vessels
- Blood
What does the heart do in the cardiovascular system?
Serves as a pump
What do the blood vessels do in the cardiovascular system?
Passageways for blood to travel to all parts of the body and back to the heart
What does the blood do in the cardiovascular system?
Act as a transport medium
What is the main goal of the cardiovascular system?
To transport materials throughout the body
What would be categorized as normal in terms of hypertension
Mean SBP/DBP < 120/80 mmHg
SBP: systolic blood pressure
DBP: diastolic blood pressure
What would be categorized as elevated (previously pre-hypertension) in terms of hypertension
Mean SBP 120-129 mmHg and DBP < 80 mmHg
SBP: systolic blood pressure
DBP: diastolic blood pressure
What would be categorized as stage 1 (previously pre-hypertension) hypertension
Mean SBP 130-139 mmHg OR mean DBP 80-89 mmHg
What would be categorized as stage 2 (previously hypertension) hypertension
Mean SBP ≥ 140 mmHg OR mean DBP ≥ 90 mmHg OR
Self-reported use of medication for high blood pressure within the past month OR self-reported having been diagnosed with hypertension by a health-care professional
Individuals with SBP and DBP in 2 categories, the category should be designated to the (blank)
Higher BP categories
What are some (3) structural changes in the cardiovascular system with age?
Thickening of the walls of the large arteries
- With age, the internal layer (tunica intima) of the artery thickens and fragments - a process similar to what happens with early-stage atherosclerosis
Increased stiffness of the large arteries, small arteries, and arterioles (less compliant)
- With age, the regulation of vasodilation is impaired (vessels are less responsive to biochemical cues for dilation)
Thickening of the walls of the left ventricle
What is heart rate?
The number of times the heart beats in one minute
Is the average resting heart rate of older adults significantly different from young adults?
No. It is not significantly different
What is the difference in heartrate between ages?
Maximum HR (associated with heavy exercise), decreases 5-10 beats per minute each decade
What is the maximum heart rate calculation for individuals over 40 years
208 - (0.7 x age)
What is stroke volume?
The amount of blood (in ml) pumped from the heart with each beat
What are the changes in stroke volume with age?
Resting supine stroke volume showed little change with aging in men or women
With age, stroke volume changes, in response to increased activity, do not happen as efficiently due to several factors
What is cardiac output?
The total amount of blood ejected from each ventricle of the heart in 1 minute, expressed in liters per minute (L/min)
Cardiac Output = Stroke volume x Heart Rate
Q = SV x HR
What are the changes in cardiac output with age?
At rest, not a big difference
Older adults cannot modulate stroke volume at maximum exercise, and heart rate max is blunted. Yes, there is a change
What is Arteriovenous Oxygen ((av)O2) Difference
The difference between the amount of oxygen transported in the arterial blood and the amount of oxygen transported in the mixed venous blood
At rest, what is the (a-v)O2 difference
~5 ml O2/100 ml blood
During maximal exercise, what is the (a-v)O2 difference?
~ 15 ml O2/100 ml blood
What are the differences in arteriovenous oxygen ((av)O2) with age
With age, (a-v)O2 difference decreases
- E.g. 65 yr old male has an (a-v)O2 difference 20-40% lower than a 25 yr old male
What is maximal aerobic capacity (VO2max)?
The maximal rate at which oxygen can be taken up,
distributed, and used by the body during exercise that
engages a large muscle mass (measured in ml * kg-1 * min-1)
VO2max = Cardiac Output X (a-v)O2 difference
How does age change VO2max?
VO2max declines about 1% per year for each year after age 25
What is the cardiopulmonary system?
The heart operates in partnership with the lungs to ensure the efficient transport of blood to and from the heart to facilitate the exchange of oxygen and carbon dioxide
What are some (4) structural changes in the cardiopulmonary system with age?
Reduction in alveolar surface area = less surface area for gas exchange to occur
Loss of elastic recoil of the lungs = increase work required for respiration
Increased chest wall stiffness = increase work required for respiration
Decreased inspiratory muscle strength (e.g. diaphragm, intercostals) = increase work required for respiration
Cardiopulmonary system structural changes: reduction in alveolar surface area
Less surface area for gas exchange to occur
Cardiopulmonary system structural changes: loss of elastic recoil of the lungs
Increase work required for respiration
Cardiopulmonary system structural changes: increased chest wall stiffness
Increase work required for respiration
Cardiopulmonary system structural changes: decreased inspiratory muscle strength (e.g. diaphragm, intercostals)
Increase work required for respiration
